Merge remote-tracking branch 'savannah/master' into native-comp

194 files changed, 5187 insertions, 2655 deletions

diff --git a/.clang-format b/.clang-format
index 9ab09a86ff2..44200a39952 100644
--- a/.clang-format
+++ b/.clang-format
@@ -1,5 +1,5 @@
 Language: Cpp
-BasedOnStyle: LLVM
+BasedOnStyle: GNU
 AlignEscapedNewlinesLeft: true
 AlwaysBreakAfterReturnType: TopLevelDefinitions
 BreakBeforeBinaryOperators: All
diff --git a/.gitignore b/.gitignore
index 63fa4203b58..4c7c1ad61b7 100644
--- a/.gitignore
+++ b/.gitignore
@@ -299,4 +299,3 @@ nt/emacs.rc
 nt/emacsclient.rc
 src/gdb.ini
 /var/
-src/fingerprint.c
diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 1be92cff161..acc1649bdab 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -1,4 +1,4 @@
-# Copyright (C) 2017-2021 Free Software Foundation, Inc.
+# Copyright (C) 2021 Free Software Foundation, Inc.
 #
 #  This file is part of GNU Emacs.
 #
@@ -194,3 +194,5 @@ test-all:
   variables:
     target: emacs-inotify
     make_params: check-expensive
+# Just load from test/infra, to keep build automation files there.
+include: '/test/infra/gitlab-ci.yml'
diff --git a/build-aux/config.guess b/build-aux/config.guess
index 7f748177972..f7727026b70 100755
--- a/build-aux/config.guess
+++ b/build-aux/config.guess
@@ -1,8 +1,8 @@
 #! /bin/sh
 # Attempt to guess a canonical system name.
-#   Copyright 1992-2020 Free Software Foundation, Inc.
+#   Copyright 1992-2021 Free Software Foundation, Inc.
 
-timestamp='2020-12-22'
+timestamp='2021-01-01'
 
 # This file is free software; you can redistribute it and/or modify it
 # under the terms of the GNU General Public License as published by
@@ -50,7 +50,7 @@ version="\
 GNU config.guess ($timestamp)
 
 Originally written by Per Bothner.
-Copyright 1992-2020 Free Software Foundation, Inc.
+Copyright 1992-2021 Free Software Foundation, Inc.
 
 This is free software; see the source for copying conditions.  There is NO
 warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE."
@@ -1087,7 +1087,7 @@ EOF
     ppcle:Linux:*:*)
         echo powerpcle-unknown-linux-"$LIBC"
         exit ;;
-    riscv32:Linux:*:* | riscv64:Linux:*:*)
+    riscv32:Linux:*:* | riscv32be:Linux:*:* | riscv64:Linux:*:* | riscv64be:Linux:*:*)
         echo "$UNAME_MACHINE"-unknown-linux-"$LIBC"
         exit ;;
     s390:Linux:*:* | s390x:Linux:*:*)
diff --git a/build-aux/config.sub b/build-aux/config.sub
index 90bb8aeda63..b0f8492348d 100755
--- a/build-aux/config.sub
+++ b/build-aux/config.sub
@@ -1,8 +1,8 @@
 #! /bin/sh
 # Configuration validation subroutine script.
-#   Copyright 1992-2020 Free Software Foundation, Inc.
+#   Copyright 1992-2021 Free Software Foundation, Inc.
 
-timestamp='2020-12-22'
+timestamp='2021-01-07'
 
 # This file is free software; you can redistribute it and/or modify it
 # under the terms of the GNU General Public License as published by
@@ -67,7 +67,7 @@ Report bugs and patches to <config-patches@gnu.org>."
 version="\
 GNU config.sub ($timestamp)
 
-Copyright 1992-2020 Free Software Foundation, Inc.
+Copyright 1992-2021 Free Software Foundation, Inc.
 
 This is free software; see the source for copying conditions.  There is NO
 warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE."
@@ -1230,7 +1230,7 @@ case $cpu-$vendor in
                         | powerpc | powerpc64 | powerpc64le | powerpcle | powerpcspe \
                         | pru \
                         | pyramid \
-                        | riscv | riscv32 | riscv64 \
+                        | riscv | riscv32 | riscv32be | riscv64 | riscv64be \
                         | rl78 | romp | rs6000 | rx \
                         | s390 | s390x \
                         | score \
@@ -1687,7 +1687,7 @@ case $os in
         musl* | newlib* | uclibc*)
                 ;;
         # Likewise for "kernel-libc"
-        eabi | eabihf | gnueabi | gnueabihf)
+        eabi* | gnueabi*)
                 ;;
         # Now accept the basic system types.
         # The portable systems comes first.
diff --git a/configure.ac b/configure.ac
index 1bff666ad50..4691d5785a6 100644
--- a/configure.ac
+++ b/configure.ac
@@ -6011,7 +6011,7 @@ if test $AUTO_DEPEND = yes; then
      AS_MKDIR_P([$dir/deps])
    done
 fi
-if $gl_gnulib_enabled_scratch_buffer; then
+if $gl_gnulib_enabled_dynarray || $gl_gnulib_enabled_scratch_buffer; then
   AS_MKDIR_P([lib/malloc])
   if test $AUTO_DEPEND = yes; then
     AS_MKDIR_P([lib/deps/malloc])
diff --git a/doc/lispref/control.texi b/doc/lispref/control.texi
index 55bcddb31aa..80e9eb7dd8e 100644
--- a/doc/lispref/control.texi
+++ b/doc/lispref/control.texi
@@ -557,8 +557,9 @@ Likewise, it makes no sense to bind keyword symbols
 
 @item (pred @var{function})
 Matches if the predicate @var{function} returns non-@code{nil}
-when called on @var{expval}.
-the predicate @var{function} can have one of the following forms:
+when called on @var{expval}.  The test can be negated with the syntax
+@code{(pred (not @var{function}))}.
+The predicate @var{function} can have one of the following forms:
 
 @table @asis
 @item function name (a symbol)
diff --git a/doc/lispref/keymaps.texi b/doc/lispref/keymaps.texi
index 37bab7ea9bc..55d179b8753 100644
--- a/doc/lispref/keymaps.texi
+++ b/doc/lispref/keymaps.texi
@@ -2852,9 +2852,8 @@ Here is how to insert an item called @samp{Work} in the @samp{Signals}
 menu of Shell mode, after the item @code{break}:
 
 @example
-(define-key-after
-  (lookup-key shell-mode-map [menu-bar signals])
-  [work] '("Work" . work-command) 'break)
+(define-key-after shell-mode-map [menu-bar signals work]
+  '("Work" . work-command) 'break)
 @end example
 @end defun
 
diff --git a/doc/lispref/markers.texi b/doc/lispref/markers.texi
index cdd0938b458..b39373f0727 100644
--- a/doc/lispref/markers.texi
+++ b/doc/lispref/markers.texi
@@ -560,7 +560,9 @@ deactivate the mark.  If the value is @w{@code{(only . @var{oldval})}},
 then @code{transient-mark-mode} is set to the value @var{oldval} after
 any subsequent command that moves point and is not shift-translated
 (@pxref{Key Sequence Input, shift-translation}), or after any other
-action that would normally deactivate the mark.
+action that would normally deactivate the mark.  (Marking a region
+with the mouse will temporarily enable @code{transient-mark-mode} in
+this way.)
 @end defopt
 
 @defopt mark-even-if-inactive
diff --git a/doc/lispref/processes.texi b/doc/lispref/processes.texi
index 535cebed7a8..6dedaa31f2e 100644
--- a/doc/lispref/processes.texi
+++ b/doc/lispref/processes.texi
@@ -729,7 +729,9 @@ coding systems (@pxref{Default Coding Systems}).  On the other hand,
 it will use @var{query-flag} as its query-on-exit flag (@pxref{Query
 Before Exit}).  It will be associated with the @var{stderr} buffer
 (@pxref{Process Buffers}) and send its output (which is the standard
-error of the main process) there.
+error of the main process) there.  To get the process object for the
+standard error process, pass the @var{stderr} buffer to
+@code{get-buffer-process}.
 
 If @var{stderr} is a pipe process, Emacs will use it as standard error
 process for the new process.
@@ -1942,6 +1944,29 @@ code:
 (while (accept-process-output stderr-process))
 @end example
 
+If you passed a buffer to the @var{stderr} argument of
+@code{make-process}, you still have to wait for the standard error
+process, like so:
+
+@example
+(let* ((stdout (generate-new-buffer "stdout"))
+       (stderr (generate-new-buffer "stderr"))
+       (process (make-process :name "test"
+                              :command '("my-program")
+                              :buffer stdout
+                              :stderr stderr))
+       (stderr-process (get-buffer-process stderr)))
+  (unless (and process stderr-process)
+    (error "Process unexpectedly nil"))
+  (while (accept-process-output process))
+  (while (accept-process-output stderr-process)))
+@end example
+
+@noindent
+Only when both @code{accept-process-output} forms return @code{nil},
+you can be sure that the process has exited and Emacs has read all its
+output.
+
 Reading pending standard error from a process running on a remote host
 is not possible this way.
 
diff --git a/doc/lispref/text.texi b/doc/lispref/text.texi
index 0b567d82c61..14854a5aafa 100644
--- a/doc/lispref/text.texi
+++ b/doc/lispref/text.texi
@@ -334,6 +334,25 @@ but there is no peace.
 (thing-at-point 'whitespace)
      @result{} nil
 @end example
+
+@defvar thing-at-point-provider-alist
+This variable allows users and modes to tweak how
+@code{thing-at-point} works.  It's an association list of @var{thing}s
+and functions (called with zero parameters) to return that thing.
+Entries for @var{thing} will be evaluated in turn until a
+non-@code{nil} result is returned.
+
+For instance, a major mode could say:
+
+@lisp
+(setq-local thing-at-point-provider-alist
+            (append thing-at-point-provider-alist
+                    '((url . my-mode--url-at-point))))
+@end lisp
+
+If no providers have a non-@code{nil} return, the @var{thing} will be
+computed the standard way.
+@end defvar
 @end defun
 
 @node Comparing Text
@@ -5610,6 +5629,11 @@ This function cancels and undoes all the changes in the change group
 specified by @var{handle}.
 @end defun
 
+@defun undo-amalgamate-change-group
+Amalgamate changes in change-group since @var{handle}.  I.e., remove
+all undo boundaries between the state of @var{handle} and now.
+@end defun
+
   Your code should use @code{unwind-protect} to make sure the group is
 always finished.  The call to @code{activate-change-group} should be
 inside the @code{unwind-protect}, in case the user types @kbd{C-g}
diff --git a/doc/misc/message.texi b/doc/misc/message.texi
index f2680b4a797..be6c9a419b2 100644
--- a/doc/misc/message.texi
+++ b/doc/misc/message.texi
@@ -317,6 +317,12 @@ when forwarding a message.
 In non-@code{nil}, only headers that match this regexp will be kept
 when forwarding a message.  This can also be a list of regexps.
 
+@item message-forward-included-mime-headers
+@vindex message-forward-included-mime-headers
+In non-@code{nil}, headers that match this regexp will be kept when
+forwarding a message as @acronym{MIME}, but @acronym{MML} isn't used.
+This can also be a list of regexps.
+
 @item message-make-forward-subject-function
 @vindex message-make-forward-subject-function
 A list of functions that are called to generate a subject header for
diff --git a/doc/misc/texinfo.tex b/doc/misc/texinfo.tex
index 3c7051d1c74..dac7ae3d199 100644
--- a/doc/misc/texinfo.tex
+++ b/doc/misc/texinfo.tex
@@ -3,7 +3,7 @@
 % Load plain if necessary, i.e., if running under initex.
 \expandafter\ifx\csname fmtname\endcsname\relax\input plain\fi
 %
-\def\texinfoversion{2020-10-24.12}
+\def\texinfoversion{2020-11-25.18}
 %
 % Copyright 1985, 1986, 1988, 1990-2020 Free Software Foundation, Inc.
 %
@@ -572,10 +572,9 @@
   \fi
 }
 
-% @end foo executes the definition of \Efoo.
-% But first, it executes a specialized version of \checkenv
-%
-\parseargdef\end{%
+
+% @end foo calls \checkenv and executes the definition of \Efoo.
+\parseargdef\end{
   \if 1\csname iscond.#1\endcsname
   \else
     % The general wording of \badenverr may not be ideal.
@@ -2673,8 +2672,6 @@ end
 \definetextfontsizexi
 
 
-\message{markup,}
-
 % Check if we are currently using a typewriter font.  Since all the
 % Computer Modern typewriter fonts have zero interword stretch (and
 % shrink), and it is reasonable to expect all typewriter fonts to have
@@ -2682,68 +2679,14 @@ end
 %
 \def\ifmonospace{\ifdim\fontdimen3\font=0pt }
 
-% Markup style infrastructure.  \defmarkupstylesetup\INITMACRO will
-% define and register \INITMACRO to be called on markup style changes.
-% \INITMACRO can check \currentmarkupstyle for the innermost
-% style.
-
-\let\currentmarkupstyle\empty
-
-\def\setupmarkupstyle#1{%
-  \def\currentmarkupstyle{#1}%
-  \markupstylesetup
-}
-
-\let\markupstylesetup\empty
-
-\def\defmarkupstylesetup#1{%
-  \expandafter\def\expandafter\markupstylesetup
-    \expandafter{\markupstylesetup #1}%
-  \def#1%
-}
-
-% Markup style setup for left and right quotes.
-\defmarkupstylesetup\markupsetuplq{%
-  \expandafter\let\expandafter \temp
-    \csname markupsetuplq\currentmarkupstyle\endcsname
-  \ifx\temp\relax \markupsetuplqdefault \else \temp \fi
-}
-
-\defmarkupstylesetup\markupsetuprq{%
-  \expandafter\let\expandafter \temp
-    \csname markupsetuprq\currentmarkupstyle\endcsname
-  \ifx\temp\relax \markupsetuprqdefault \else \temp \fi
-}
-
 {
 \catcode`\'=\active
 \catcode`\`=\active
 
-\gdef\markupsetuplqdefault{\let`\lq}
-\gdef\markupsetuprqdefault{\let'\rq}
-
-\gdef\markupsetcodequoteleft{\let`\codequoteleft}
-\gdef\markupsetcodequoteright{\let'\codequoteright}
+\gdef\setcodequotes{\let`\codequoteleft \let'\codequoteright}
+\gdef\setregularquotes{\let`\lq \let'\rq}
 }
 
-\let\markupsetuplqcode \markupsetcodequoteleft
-\let\markupsetuprqcode \markupsetcodequoteright
-%
-\let\markupsetuplqexample \markupsetcodequoteleft
-\let\markupsetuprqexample \markupsetcodequoteright
-%
-\let\markupsetuplqkbd     \markupsetcodequoteleft
-\let\markupsetuprqkbd     \markupsetcodequoteright
-%
-\let\markupsetuplqsamp \markupsetcodequoteleft
-\let\markupsetuprqsamp \markupsetcodequoteright
-%
-\let\markupsetuplqverb \markupsetcodequoteleft
-\let\markupsetuprqverb \markupsetcodequoteright
-%
-\let\markupsetuplqverbatim \markupsetcodequoteleft
-\let\markupsetuprqverbatim \markupsetcodequoteright
-
 % Allow an option to not use regular directed right quote/apostrophe
 % (char 0x27), but instead the undirected quote from cmtt (char 0x0d).
 % The undirected quote is ugly, so don't make it the default, but it
@@ -2906,7 +2849,7 @@ end
 }
 
 % @samp.
-\def\samp#1{{\setupmarkupstyle{samp}\lq\tclose{#1}\rq\null}}
+\def\samp#1{{\setcodequotes\lq\tclose{#1}\rq\null}}
 
 % @indicateurl is \samp, that is, with quotes.
 \let\indicateurl=\samp
@@ -2949,8 +2892,7 @@ end
   \global\let'=\rq \global\let`=\lq  % default definitions
   %
   \global\def\code{\begingroup
-    \setupmarkupstyle{code}%
-    % The following should really be moved into \setupmarkupstyle handlers.
+    \setcodequotes
     \catcode\dashChar=\active  \catcode\underChar=\active
     \ifallowcodebreaks
      \let-\codedash
@@ -3104,7 +3046,7 @@ end
   \urefcatcodes
   %
   \global\def\urefcode{\begingroup
-    \setupmarkupstyle{code}%
+    \setcodequotes
     \urefcatcodes
     \let&\urefcodeamp
     \let.\urefcodedot
@@ -3225,8 +3167,8 @@ end
 \def\kbdsub#1#2#3\par{%
   \def\one{#1}\def\three{#3}\def\threex{??}%
   \ifx\one\xkey\ifx\threex\three \key{#2}%
-  \else{\tclose{\kbdfont\setupmarkupstyle{kbd}\look}}\fi
-  \else{\tclose{\kbdfont\setupmarkupstyle{kbd}\look}}\fi
+  \else{\tclose{\kbdfont\setcodequotes\look}}\fi
+  \else{\tclose{\kbdfont\setcodequotes\look}}\fi
 }
 
 % definition of @key that produces a lozenge.  Doesn't adjust to text size.
@@ -3243,7 +3185,7 @@ end
 % monospace, don't change it; that way, we respect @kbdinputstyle.  But
 % if it isn't monospace, then use \tt.
 %
-\def\key#1{{\setupmarkupstyle{key}%
+\def\key#1{{\setregularquotes
   \nohyphenation
   \ifmonospace\else\tt\fi
   #1}\null}
@@ -3373,16 +3315,20 @@ end
 {\obeylines
 \globaldefs=1
 \envdef\displaymath{%
-\tex
+\tex%
 \def\thisenv{\displaymath}%
+\begingroup\let\end\displaymathend%
 $$%
 }
 
-\def\Edisplaymath{$$
+\def\displaymathend{$$\endgroup\end}%
+
+\def\Edisplaymath{%
 \def\thisenv{\tex}%
 \end tex
 }}
 
+
 % @inlinefmt{FMTNAME,PROCESSED-TEXT} and @inlineraw{FMTNAME,RAW-TEXT}.
 % Ignore unless FMTNAME == tex; then it is like @iftex and @tex,
 % except specified as a normal braced arg, so no newlines to worry about.
@@ -7144,7 +7090,7 @@ might help (with 'rm \jobname.?? \jobname.??s')%
 % But \@ or @@ will get a plain @ character.
 
 \envdef\tex{%
-  \setupmarkupstyle{tex}%
+  \setregularquotes
   \catcode `\\=0 \catcode `\{=1 \catcode `\}=2
   \catcode `\$=3 \catcode `\&=4 \catcode `\#=6
   \catcode `\^=7 \catcode `\_=8 \catcode `\~=\active \let~=\tie
@@ -7370,7 +7316,7 @@ might help (with 'rm \jobname.?? \jobname.??s')%
 % If you want all examples etc. small: @set dispenvsize small.
 % If you want even small examples the full size: @set dispenvsize nosmall.
 % This affects the following displayed environments:
-%    @example, @display, @format, @lisp
+%    @example, @display, @format, @lisp, @verbatim
 %
 \def\smallword{small}
 \def\nosmallword{nosmall}
@@ -7416,9 +7362,9 @@ might help (with 'rm \jobname.?? \jobname.??s')%
 %
 \maketwodispenvdef{lisp}{example}{%
   \nonfillstart
-  \tt\setupmarkupstyle{example}%
+  \tt\setcodequotes
   \let\kbdfont = \kbdexamplefont % Allow @kbd to do something special.
-  \gobble % eat return
+  \parsearg\gobble
 }
 % @display/@smalldisplay: same as @lisp except keep current font.
 %
@@ -7576,7 +7522,7 @@ might help (with 'rm \jobname.?? \jobname.??s')%
 \def\setupverb{%
   \tt  % easiest (and conventionally used) font for verbatim
   \def\par{\leavevmode\endgraf}%
-  \setupmarkupstyle{verb}%
+  \setcodequotes
   \tabeightspaces
   % Respect line breaks,
   % print special symbols as themselves, and
@@ -7617,7 +7563,7 @@ might help (with 'rm \jobname.?? \jobname.??s')%
   \tt % easiest (and conventionally used) font for verbatim
   \def\par{\egroup\leavevmode\box\verbbox\endgraf\starttabbox}%
   \tabexpand
-  \setupmarkupstyle{verbatim}%
+  \setcodequotes
   % Respect line breaks,
   % print special symbols as themselves, and
   % make each space count.
@@ -8036,7 +7982,7 @@ might help (with 'rm \jobname.?? \jobname.??s')%
   % leave the code in, but it's strange for @var to lead to typewriter.
   % Nowadays we recommend @code, since the difference between a ttsl hyphen
   % and a tt hyphen is pretty tiny.  @code also disables ?` !`.
-  \def\var##1{{\setupmarkupstyle{var}\ttslanted{##1}}}%
+  \def\var##1{{\setregularquotes\ttslanted{##1}}}%
   #1%
   \sl\hyphenchar\font=45
 }
@@ -8145,11 +8091,18 @@ might help (with 'rm \jobname.?? \jobname.??s')%
   }
 \fi
 
+\let\E=\expandafter
+
 % Used at the time of macro expansion.
 % Argument is macro body with arguments substituted
 \def\scanmacro#1{%
   \newlinechar`\^^M
-  \def\xeatspaces{\eatspaces}%
+  % expand the expansion of \eatleadingcr twice to maybe remove a leading
+  % newline (and \else and \fi tokens), then call \eatspaces on the result.
+  \def\xeatspaces##1{%
+    \E\E\E\E\E\E\E\eatspaces\E\E\E\E\E\E\E{\eatleadingcr##1%
+  }}%
+  \def\xempty##1{}%
   %
   % Process the macro body under the current catcode regime.
   \scantokens{#1@comment}%
@@ -8202,6 +8155,11 @@ might help (with 'rm \jobname.?? \jobname.??s')%
 \unbrace{\gdef\trim@@@ #1 } #2@{#1}
 }
 
+{\catcode`\^^M=\other%
+\gdef\eatleadingcr#1{\if\noexpand#1\noexpand^^M\else\E#1\fi}}%
+% Warning: this won't work for a delimited argument
+% or for an empty argument
+
 % Trim a single trailing ^^M off a string.
 {\catcode`\^^M=\other \catcode`\Q=3%
 \gdef\eatcr #1{\eatcra #1Q^^MQ}%
@@ -8368,6 +8326,7 @@ might help (with 'rm \jobname.?? \jobname.??s')%
   \let\hash\relax
   % \hash is redefined to `#' later to get it into definitions
   \let\xeatspaces\relax
+  \let\xempty\relax
   \parsemargdefxxx#1,;,%
   \ifnum\paramno<10\relax\else
     \paramno0\relax
@@ -8379,9 +8338,11 @@ might help (with 'rm \jobname.?? \jobname.??s')%
   \else \let\next=\parsemargdefxxx
     \advance\paramno by 1
     \expandafter\edef\csname macarg.\eatspaces{#1}\endcsname
-        {\xeatspaces{\hash\the\paramno}}%
+        {\xeatspaces{\hash\the\paramno\noexpand\xempty{}}}%
     \edef\paramlist{\paramlist\hash\the\paramno,}%
   \fi\next}
+% the \xempty{} is to give \eatleadingcr an argument in the case of an
+% empty macro argument.
 
 % \parsemacbody, \parsermacbody
 %
@@ -9107,20 +9068,22 @@ might help (with 'rm \jobname.?? \jobname.??s')%
       % output the `[mynode]' via the macro below so it can be overridden.
       \xrefprintnodename\printedrefname
       %
-      % But we always want a comma and a space:
-      ,\space
-      %
-      % output the `page 3'.
-      \turnoffactive \putwordpage\tie\refx{#1-pg}{}%
-      % Add a , if xref followed by a space
-      \if\space\noexpand\tokenafterxref ,%
-      \else\ifx\        \tokenafterxref ,% @TAB
-      \else\ifx\*\tokenafterxref ,%   @*
-      \else\ifx\ \tokenafterxref ,%   @SPACE
-      \else\ifx\
-                \tokenafterxref ,%    @NL
-      \else\ifx\tie\tokenafterxref ,% @tie
-      \fi\fi\fi\fi\fi\fi
+      \expandafter\ifx\csname SETtxiomitxrefpg\endcsname\relax
+        % But we always want a comma and a space:
+        ,\space
+        %
+        % output the `page 3'.
+        \turnoffactive \putwordpage\tie\refx{#1-pg}{}%
+        % Add a , if xref followed by a space
+        \if\space\noexpand\tokenafterxref ,%
+        \else\ifx\      \tokenafterxref ,% @TAB
+        \else\ifx\*\tokenafterxref ,%   @*
+        \else\ifx\ \tokenafterxref ,%   @SPACE
+        \else\ifx\
+                  \tokenafterxref ,%    @NL
+        \else\ifx\tie\tokenafterxref ,% @tie
+        \fi\fi\fi\fi\fi\fi
+      \fi
     \fi\fi
   \fi
   \endlink
@@ -9550,7 +9513,7 @@ might help (with 'rm \jobname.?? \jobname.??s')%
 \def\imagexxx#1,#2,#3,#4,#5,#6\finish{\begingroup
   \catcode`\^^M = 5     % in case we're inside an example
   \normalturnoffactive  % allow _ et al. in names
-  \def\xprocessmacroarg{\eatspaces}% in case we are being used via a macro
+  \makevalueexpandable
   % If the image is by itself, center it.
   \ifvmode
     \imagevmodetrue
@@ -11603,7 +11566,7 @@ directory should work if nowhere else does.}
   \let> = \activegtr
   \let~ = \activetilde
   \let^ = \activehat
-  \markupsetuplqdefault \markupsetuprqdefault
+  \setregularquotes
   \let\b = \strong
   \let\i = \smartitalic
   % in principle, all other definitions in \tex have to be undone too.
@@ -11662,8 +11625,7 @@ directory should work if nowhere else does.}
    @let|=@normalverticalbar
    @let~=@normaltilde
    @let\=@ttbackslash
-   @markupsetuplqdefault
-   @markupsetuprqdefault
+   @setregularquotes
    @unsepspaces
  }
 }
@@ -11756,8 +11718,7 @@ directory should work if nowhere else does.}
 @c Do this last of all since we use ` in the previous @catcode assignments.
 @catcode`@'=@active
 @catcode`@`=@active
-@markupsetuplqdefault
-@markupsetuprqdefault
+@setregularquotes
 
 @c Local variables:
 @c eval: (add-hook 'before-save-hook 'time-stamp)
diff --git a/doc/misc/tramp.texi b/doc/misc/tramp.texi
index 2c4b792cc21..5d89b065882 100644
--- a/doc/misc/tramp.texi
+++ b/doc/misc/tramp.texi
@@ -810,9 +810,10 @@ behavior.
 @cindex @option{sshx} method
 
 Works like @option{ssh} but without the extra authentication prompts.
-@option{sshx} uses @samp{ssh -t -t @var{host} -l @var{user} /bin/sh}
-to open a connection with a ``standard'' login shell.  It supports
-changing the remote login shell @command{/bin/sh}.
+@option{sshx} uses @samp{ssh -t -t -l @var{user} -o
+RemoteCommand='/bin/sh -i' @var{host}} to open a connection with a
+``standard'' login shell.  It supports changing the remote login shell
+@command{/bin/sh}.
 
 @strong{Note} that @option{sshx} does not bypass authentication
 questions.  For example, if the host key of the remote host is not
@@ -935,9 +936,10 @@ This method supports the @samp{-p} argument.
 @cindex @command{ssh} (with @option{scpx} method)
 
 @option{scpx} is useful to avoid login shell questions.  It is similar
-in performance to @option{scp}.  @option{scpx} uses @samp{ssh -t -t
-@var{host} -l @var{user} /bin/sh} to open a connection.  It supports
-changing the remote login shell @command{/bin/sh}.
+in performance to @option{scp}.  @option{scpx} uses @samp{ssh -t -t -l
+@var{user} -o RemoteCommand='/bin/sh -i' @var{host}} to open a
+connection.  It supports changing the remote login shell
+@command{/bin/sh}.
 
 @option{scpx} is useful for MS Windows users when @command{ssh}
 triggers an error about allocating a pseudo tty.  This happens due to
@@ -2220,7 +2222,10 @@ This uses also the settings in @code{tramp-sh-extra-args}.
 @vindex RemoteCommand@r{, ssh option}
 @strong{Note}: If you use an @option{ssh}-based method for connection,
 do @emph{not} set the @option{RemoteCommand} option in your
-@command{ssh} configuration, for example to @command{screen}.
+@command{ssh} configuration, for example to @command{screen}.  On the
+other hand, some @option{ssh}-based methods, like @option{sshx} or
+@option{scpx}, silently overwrite a @option{RemoteCommand} option of
+the configuration file.
 
 
 @subsection Other remote shell setup hints
@@ -2369,8 +2374,7 @@ that can identify such questions using
 @lisp
 @group
 (defconst my-tramp-prompt-regexp
-  (concat (regexp-opt '("Enter the birth date of your mother:") t)
-          "\\s-*")
+  "Enter the birth date of your mother:\\s-*"
   "Regular expression matching my login prompt question.")
 @end group
 
@@ -2389,6 +2393,11 @@ that can identify such questions using
 @end group
 @end lisp
 
+The regular expressions used in @code{tramp-actions-before-shell} must
+match the end of the connection buffer.  Due to performance reasons,
+this search starts at the end of the buffer, and it is limited to 256
+characters backwards.
+
 
 @item Conflicting names for users and variables in @file{.profile}
 
@@ -3576,7 +3585,6 @@ Furthermore, this approach has the following limitations:
 It works only for connection methods defined in @file{tramp-sh.el} and
 @file{tramp-adb.el}.
 
-@vindex ControlMaster@r{, ssh option}
 @item
 It does not support interactive user authentication.  With
 @option{ssh}-based methods, this can be avoided by using a password
@@ -3584,6 +3592,10 @@ agent like @command{ssh-agent}, using public key authentication, or
 using @option{ControlMaster} options.
 
 @item
+It cannot be applied for @option{ssh}-based methods, which use the
+@option{RemoteCommand} option.
+
+@item
 It cannot be killed via @code{interrupt-process}.
 
 @item
@@ -3593,8 +3605,7 @@ It does not report the remote terminal name via @code{process-tty-name}.
 It does not set process property @code{remote-pid}.
 
 @item
-It does not use @code{tramp-remote-path} and
-@code{tramp-remote-process-environment}.
+It does not use @code{tramp-remote-path}.
 @end itemize
 
 In order to gain even more performance, it is recommended to bind
diff --git a/etc/HELLO b/etc/HELLO
index dec3a775afb..0cebb2bb7c2 100644
--- a/etc/HELLO
+++ b/etc/HELLO
@@ -30,20 +30,16 @@ Bengali (বাংলা)	নমস্কার
 Braille ⠓⠑⠇⠇⠕
 Burmese (မြန်မာ)    မင်္ဂလာပါ
 C       printf ("Hello, world!\n");
+Cham (ꨌꩌ)   ꨦꨤꩌ ꨦꨁꨰ
 Cherokee (ᏣᎳᎩ ᎦᏬᏂᎯᏍᏗ) ᎣᏏᏲ / ᏏᏲ
 Comanche /kəˈmæntʃiː/      Haa marʉ́awe
-
 Cree (ᓀᐦᐃᔭᐍᐏᐣ)    ᑕᓂᓯ / ᐙᒋᔮ
-
 Czech (čeština)       Dobrý den
 Danish (dansk)  Hej / Goddag / Halløj
 Dutch (Nederlands)      Hallo / Dag
 Efik  /ˈɛfɪk/        Mɔkɔm
-
 Egyptian Hieroglyphs (𓂋𓐰𓏤𓈖𓆎𓅓𓏏𓐰𓊖)     𓅓𓊵𓐰𓐷𓏏𓊪𓐸, 𓇍𓇋𓂻𓍘𓇋
-
 Emacs   emacs --no-splash -f view-hello-file
-
 Emoji   👋
 English /ˈɪŋɡlɪʃ/ Hello
 Esperanto       Saluton (Eĥoŝanĝo ĉiuĵaŭde)
@@ -59,7 +55,6 @@ Hebrew (עִבְרִית)	שָׁלוֹם
 Hungarian (magyar)      Szép jó napot!
 Hindi (हिंदी) नमस्ते / नमस्कार ।
 Inuktitut (ᐃᓄᒃᑎᑐᑦ)  ᐊᐃ
-
 Italian (italiano)      Ciao / Buon giorno
 Javanese (ꦧꦱꦗꦮꦶ)      console.log("ꦲꦭꦺꦴ");
 Kannada (ಕನ್ನಡ)       ನಮಸ್ಕಾರ
@@ -67,7 +62,6 @@ Khmer (ភាសាខ្មែរ)	ជំរាបសួរ
 Lao (ພາສາລາວ)     ສະບາຍດີ / ຂໍໃຫ້ໂຊກດີ
 Malayalam (മലയാളം)  നമസ്കാരം
 Maldivian (ދިވެހި)        އައްސަލާމު ޢަލައިކުމް / ކިހިނެހް؟
-
 Maltese (il-Malti)      Bonġu / Saħħa
 Mathematics     ∀ p ∈ world • hello p  □
 Mongolian (монгол хэл) Сайн байна уу?
@@ -83,7 +77,6 @@ Swedish (svenska)	Hej / Goddag / Hallå
 Tamil (தமிழ்) வணக்கம்
 Telugu (తెలుగు)     నమస్కారం
 TaiViet (ꪁꪫꪱꪣ ꪼꪕ)   ꪅꪰꪙꫂ ꪨꪮꫂ ꪁꪫꪱ / ꪅꪽ ꪨꪷ ꪁꪫꪱ
-
 Thai (ภาษาไทย)    สวัสดีครับ / สวัสดีค่ะ
 Tibetan (བོད་སྐད་)      བཀྲ་ཤིས་བདེ་ལེགས༎
 Tigrigna (ትግርኛ) ሰላማት
@@ -97,7 +90,6 @@ Vietnamese (tiếng Việt)	Chào bạn
 </x-charset><x-charset><param>chinese-gb2312</param>Chinese (中文,普通话,汉语)   你好
 </x-charset><x-charset><param>chinese-big5-1</param>Cantonese (粵語,廣東話)        早晨, 你好
 </x-charset><x-charset><param>korean-ksc5601</param>Korean (한글)     안녕하세요 / 안녕하십니까
-
 </x-charset>
 
 
diff --git a/etc/NEWS b/etc/NEWS
index 19ad35032a2..6b1cdaaf005 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -326,6 +326,16 @@ the buffer cycles the whole buffer between "only top-level headings",
 
 * Changes in Specialized Modes and Packages in Emacs 28.1
 
+** 'blink-cursor-mode' is now enabled by default regardless of the UI.
+It used to be enabled when Emacs is started in GUI mode but not when started
+in text mode.  The cursor still only actually blinks in GUI frames.
+
+** pcase
++++
+*** The `pred` pattern can now take the form (pred (not FUN)).
+This is like (pred (lambda (x) (not (FUN x)))) but results
+in better code.
+
 +++
 ** profiler.el
 The results displayed by 'profiler-report' now have the usage figures
@@ -346,6 +356,12 @@ When emacsclient connects, Emacs will (by default) output a message
 about how to exit the client frame.  If 'server-client-instructions'
 is set to nil, this message is inhibited.
 
+** Perl mode
+
+---
+*** New face 'perl-non-scalar-variable'.
+This is used to fontify non-scalar variables.
+
 ** Python mode
 
 *** 'python-shell-interpreter' now defaults to python3 on systems with python3.
@@ -705,9 +721,11 @@ not.
 ---
 *** Respect 'message-forward-ignored-headers' more.
 Previously, this variable would not be consulted if
-'message-forward-show-mml' was nil.  It's now always used, except if
-'message-forward-show-mml' is 'best', and we're forwarding an
-encrypted/signed message.
+'message-forward-show-mml' was nil and forwarding as MIME.
+
++++
+*** New user option 'message-forward-included-mime-headers'.
+This is used when forwarding messages as MIME, but not using MML.
 
 +++
 *** Message now supports the OpenPGP header.
@@ -821,6 +839,10 @@ so e.g. like 'C-x 8 [' inserts a left single quotation mark,
 Added a new Mozhi scheme.  The inapplicable ITRANS scheme is now
 deprecated.  Errors in the Inscript method were corrected.
 
+---
+*** New input method 'cham'.
+There's also a Cham greeting in 'etc/HELLO'.
+
 ** Ispell
 
 +++
@@ -1538,9 +1560,28 @@ buttons in it.
 This function takes a string and returns a string propertized in a way
 that makes it a valid button.
 
+** subr-x
++++
+*** A number of new string manipulation functions have been added.
+'string-clean-whitespace', 'string-fill', 'string-limit',
+'string-lines', 'string-pad' and 'string-chop-newline'.
+
+*** New macro `named-let` that provides Scheme's "named let" looping construct
+
+** thingatpt
+
++++
+*** New variable 'thing-at-point-provider-alist'.
+This allows mode-specific alterations to how `thing-at-point' works.
 
 ** Miscellaneous
 
+---
+*** New user option 'remember-diary-regexp'.
+
+---
+*** New user option 'remember-text-format-function'.
+
 *** New function 'buffer-line-statistics'.
 This function returns some statistics about the line lengths in a buffer.
 
@@ -1572,11 +1613,6 @@ length to a number).
 This can be set to nil to inhibit hiding passwords in ".authinfo" files.
 
 +++
-*** A number of new string manipulation functions have been added.
-'string-clean-whitespace', 'string-fill', 'string-limit',
-'string-lines', 'string-pad' and 'string-chop-newline'.
-
-+++
 *** New variable 'current-minibuffer-command'.
 This is like 'this-command', but it is bound recursively when entering
 the minibuffer.
diff --git a/etc/NEWS.19 b/etc/NEWS.19
index 43235e0e154..f2cef62971b 100644
--- a/etc/NEWS.19
+++ b/etc/NEWS.19
@@ -2824,6 +2824,8 @@ the text of the region according to the new value.
 the fill-column has been exceeded; the function can determine on its
 own whether filling (or justification) is necessary.
 
+**** New helper function 'indent-line-to'
+
 ** Processes
 
 *** process-tty-name is a new function that returns the name of the
diff --git a/lib/_Noreturn.h b/lib/_Noreturn.h
index 38afe1d5672..fb718bc0691 100644
--- a/lib/_Noreturn.h
+++ b/lib/_Noreturn.h
@@ -26,14 +26,16 @@
        AIX system header files and several gnulib header files use precisely
        this syntax with 'extern'.  */
 #  define _Noreturn [[noreturn]]
-# elif ((!defined __cplusplus || defined __clang__)                     \
-        && (201112 <= (defined __STDC_VERSION__ ? __STDC_VERSION__ : 0)  \
-            || 4 < __GNUC__ + (7 <= __GNUC_MINOR__) \
-            || (defined __apple_build_version__ \
-                ? 6000000 <= __apple_build_version__ \
-                : 3 < __clang_major__ + (5 <= __clang_minor__))))
+# elif ((!defined __cplusplus || defined __clang__) \
+        && (201112 <= (defined __STDC_VERSION__ ? __STDC_VERSION__ : 0) \
+            || (!defined __STRICT_ANSI__ \
+                && (__4 < __GNUC__ + (7 <= __GNUC_MINOR__) \
+                    || (defined __apple_build_version__ \
+                        ? 6000000 <= __apple_build_version__ \
+                        : 3 < __clang_major__ + (5 <= __clang_minor__))))))
    /* _Noreturn works as-is.  */
-# elif 2 < __GNUC__ + (8 <= __GNUC_MINOR__) || 0x5110 <= __SUNPRO_C
+# elif (2 < __GNUC__ + (8 <= __GNUC_MINOR__) || defined __clang__ \
+        || 0x5110 <= __SUNPRO_C)
 #  define _Noreturn __attribute__ ((__noreturn__))
 # elif 1200 <= (defined _MSC_VER ? _MSC_VER : 0)
 #  define _Noreturn __declspec (noreturn)
diff --git a/lib/canonicalize-lgpl.c b/lib/canonicalize-lgpl.c
index b6dc3a447ab..b7dba08994d 100644
--- a/lib/canonicalize-lgpl.c
+++ b/lib/canonicalize-lgpl.c
@@ -85,10 +85,6 @@
 # define IF_LINT(Code) /* empty */
 #endif
 
-/* True if adding two valid object sizes might overflow idx_t.
-   As a practical matter, this cannot happen on 64-bit machines.  */
-enum { NARROW_ADDRESSES = IDX_MAX >> 31 >> 31 == 0 };
-
 #ifndef DOUBLE_SLASH_IS_DISTINCT_ROOT
 # define DOUBLE_SLASH_IS_DISTINCT_ROOT false
 #endif
@@ -145,11 +141,11 @@ suffix_requires_dir_check (char const *end)
    macOS 10.13 <https://bugs.gnu.org/30350>, and should also work on
    platforms like AIX 7.2 that need at least "/.".  */
 
-#if defined _LIBC || defined LSTAT_FOLLOWS_SLASHED_SYMLINK
+# if defined _LIBC || defined LSTAT_FOLLOWS_SLASHED_SYMLINK
 static char const dir_suffix[] = "/";
-#else
+# else
 static char const dir_suffix[] = "/./";
-#endif
+# endif
 
 /* Return true if DIR is a searchable dir, false (setting errno) otherwise.
    DIREND points to the NUL byte at the end of the DIR string.
@@ -191,13 +187,13 @@ get_path_max (void)
    to pacify GCC is known; even an explicit #pragma does not pacify GCC.
    When the GCC bug is fixed this workaround should be limited to the
    broken GCC versions.  */
-#if __GNUC_PREREQ (10, 1)
-# if defined GCC_LINT || defined lint
+# if __GNUC_PREREQ (10, 1)
+#  if defined GCC_LINT || defined lint
 __attribute__ ((__noinline__))
-# elif __OPTIMIZE__ && !__NO_INLINE__
-#  define GCC_BOGUS_WRETURN_LOCAL_ADDR
+#  elif __OPTIMIZE__ && !__NO_INLINE__
+#   define GCC_BOGUS_WRETURN_LOCAL_ADDR
+#  endif
 # endif
-#endif
 static char *
 realpath_stk (const char *name, char *resolved,
               struct scratch_buffer *rname_buf)
@@ -343,7 +339,7 @@ realpath_stk (const char *name, char *resolved,
               if (end_in_extra_buffer)
                 end_idx = end - extra_buf;
               size_t len = strlen (end);
-              if (NARROW_ADDRESSES && INT_ADD_OVERFLOW (len, n))
+              if (INT_ADD_OVERFLOW (len, n))
                 {
                   __set_errno (ENOMEM);
                   goto error_nomem;
@@ -443,7 +439,8 @@ __realpath (const char *name, char *resolved)
 }
 libc_hidden_def (__realpath)
 versioned_symbol (libc, __realpath, realpath, GLIBC_2_3);
-#endif /* !FUNC_REALPATH_WORKS || defined _LIBC */
+
+#endif /* defined _LIBC || !FUNC_REALPATH_WORKS */
 
 
 #if SHLIB_COMPAT(libc, GLIBC_2_0, GLIBC_2_3)
diff --git a/lib/cdefs.h b/lib/cdefs.h
index 2a3dc9666b9..17a0919cd83 100644
--- a/lib/cdefs.h
+++ b/lib/cdefs.h
@@ -25,7 +25,7 @@
 
 /* The GNU libc does not support any K&R compilers or the traditional mode
    of ISO C compilers anymore.  Check for some of the combinations not
-   anymore supported.  */
+   supported anymore.  */
 #if defined __GNUC__ && !defined __STDC__
 # error "You need a ISO C conforming compiler to use the glibc headers"
 #endif
@@ -34,31 +34,26 @@
 #undef  __P
 #undef  __PMT
 
-/* Compilers that are not clang may object to
-       #if defined __clang__ && __has_attribute(...)
-   even though they do not need to evaluate the right-hand side of the &&.  */
-#if defined __clang__ && defined __has_attribute
-# define __glibc_clang_has_attribute(name) __has_attribute (name)
+/* Compilers that lack __has_attribute may object to
+       #if defined __has_attribute && __has_attribute (...)
+   even though they do not need to evaluate the right-hand side of the &&.
+   Similarly for __has_builtin, etc.  */
+#if (defined __has_attribute \
+     && (!defined __clang_minor__ \
+         || 3 < __clang_major__ + (5 <= __clang_minor__)))
+# define __glibc_has_attribute(attr) __has_attribute (attr)
 #else
-# define __glibc_clang_has_attribute(name) 0
+# define __glibc_has_attribute(attr) 0
 #endif
-
-/* Compilers that are not clang may object to
-       #if defined __clang__ && __has_builtin(...)
-   even though they do not need to evaluate the right-hand side of the &&.  */
-#if defined __clang__ && defined __has_builtin
-# define __glibc_clang_has_builtin(name) __has_builtin (name)
+#ifdef __has_builtin
+# define __glibc_has_builtin(name) __has_builtin (name)
 #else
-# define __glibc_clang_has_builtin(name) 0
+# define __glibc_has_builtin(name) 0
 #endif
-
-/* Compilers that are not clang may object to
-       #if defined __clang__ && __has_extension(...)
-   even though they do not need to evaluate the right-hand side of the &&.  */
-#if defined __clang__ && defined __has_extension
-# define __glibc_clang_has_extension(ext) __has_extension (ext)
+#ifdef __has_extension
+# define __glibc_has_extension(ext) __has_extension (ext)
 #else
-# define __glibc_clang_has_extension(ext) 0
+# define __glibc_has_extension(ext) 0
 #endif
 
 #if defined __GNUC__ || defined __clang__
@@ -74,22 +69,26 @@
 # endif
 
 /* GCC can always grok prototypes.  For C++ programs we add throw()
-   to help it optimize the function calls.  But this works only with
+   to help it optimize the function calls.  But this only works with
    gcc 2.8.x and egcs.  For gcc 3.4 and up we even mark C functions
    as non-throwing using a function attribute since programs can use
    the -fexceptions options for C code as well.  */
 # if !defined __cplusplus \
-     && (__GNUC_PREREQ (3, 4) || __glibc_clang_has_attribute (__nothrow__))
+     && (__GNUC_PREREQ (3, 4) || __glibc_has_attribute (__nothrow__))
 #  define __THROW       __attribute__ ((__nothrow__ __LEAF))
 #  define __THROWNL     __attribute__ ((__nothrow__))
 #  define __NTH(fct)    __attribute__ ((__nothrow__ __LEAF)) fct
 #  define __NTHNL(fct)  __attribute__ ((__nothrow__)) fct
 # else
 #  if defined __cplusplus && (__GNUC_PREREQ (2,8) || __clang_major >= 4)
-#   define __THROW      throw ()
-#   define __THROWNL    throw ()
-#   define __NTH(fct)   __LEAF_ATTR fct throw ()
-#   define __NTHNL(fct) fct throw ()
+#   if __cplusplus >= 201103L
+#    define __THROW     noexcept (true)
+#   else
+#    define __THROW     throw ()
+#   endif
+#   define __THROWNL    __THROW
+#   define __NTH(fct)   __LEAF_ATTR fct __THROW
+#   define __NTHNL(fct) fct __THROW
 #  else
 #   define __THROW
 #   define __THROWNL
@@ -142,24 +141,20 @@
 #define __bos(ptr) __builtin_object_size (ptr, __USE_FORTIFY_LEVEL > 1)
 #define __bos0(ptr) __builtin_object_size (ptr, 0)
 
+/* Use __builtin_dynamic_object_size at _FORTIFY_SOURCE=3 when available.  */
+#if __USE_FORTIFY_LEVEL == 3 && __glibc_clang_prereq (9, 0)
+# define __glibc_objsize0(__o) __builtin_dynamic_object_size (__o, 0)
+# define __glibc_objsize(__o) __builtin_dynamic_object_size (__o, 1)
+#else
+# define __glibc_objsize0(__o) __bos0 (__o)
+# define __glibc_objsize(__o) __bos (__o)
+#endif
+
 #if __GNUC_PREREQ (4,3)
-# define __warndecl(name, msg) \
-  extern void name (void) __attribute__((__warning__ (msg)))
 # define __warnattr(msg) __attribute__((__warning__ (msg)))
 # define __errordecl(name, msg) \
   extern void name (void) __attribute__((__error__ (msg)))
-#elif __glibc_clang_has_attribute (__diagnose_if__) && 0
-/* These definitions are not enabled, because they produce bogus warnings
-   in the glibc Fortify functions.  These functions are written in a style
-   that works with GCC.  In order to work with clang, these functions would
-   need to be modified.  */
-# define __warndecl(name, msg) \
-  extern void name (void) __attribute__((__diagnose_if__ (1, msg, "warning")))
-# define __warnattr(msg) __attribute__((__diagnose_if__ (1, msg, "warning")))
-# define __errordecl(name, msg) \
-  extern void name (void) __attribute__((__diagnose_if__ (1, msg, "error")))
 #else
-# define __warndecl(name, msg) extern void name (void)
 # define __warnattr(msg)
 # define __errordecl(name, msg) extern void name (void)
 #endif
@@ -233,7 +228,7 @@
 /* At some point during the gcc 2.96 development the `malloc' attribute
    for functions was introduced.  We don't want to use it unconditionally
    (although this would be possible) since it generates warnings.  */
-#if __GNUC_PREREQ (2,96) || __glibc_clang_has_attribute (__malloc__)
+#if __GNUC_PREREQ (2,96) || __glibc_has_attribute (__malloc__)
 # define __attribute_malloc__ __attribute__ ((__malloc__))
 #else
 # define __attribute_malloc__ /* Ignore */
@@ -251,23 +246,31 @@
 /* At some point during the gcc 2.96 development the `pure' attribute
    for functions was introduced.  We don't want to use it unconditionally
    (although this would be possible) since it generates warnings.  */
-#if __GNUC_PREREQ (2,96) || __glibc_clang_has_attribute (__pure__)
+#if __GNUC_PREREQ (2,96) || __glibc_has_attribute (__pure__)
 # define __attribute_pure__ __attribute__ ((__pure__))
 #else
 # define __attribute_pure__ /* Ignore */
 #endif
 
 /* This declaration tells the compiler that the value is constant.  */
-#if __GNUC_PREREQ (2,5) || __glibc_clang_has_attribute (__const__)
+#if __GNUC_PREREQ (2,5) || __glibc_has_attribute (__const__)
 # define __attribute_const__ __attribute__ ((__const__))
 #else
 # define __attribute_const__ /* Ignore */
 #endif
 
+#if defined __STDC_VERSION__ && 201710L < __STDC_VERSION__
+# define __attribute_maybe_unused__ [[__maybe_unused__]]
+#elif __GNUC_PREREQ (2,7) || __glibc_has_attribute (__unused__)
+# define __attribute_maybe_unused__ __attribute__ ((__unused__))
+#else
+# define __attribute_maybe_unused__ /* Ignore */
+#endif
+
 /* At some point during the gcc 3.1 development the `used' attribute
    for functions was introduced.  We don't want to use it unconditionally
    (although this would be possible) since it generates warnings.  */
-#if __GNUC_PREREQ (3,1) || __glibc_clang_has_attribute (__used__)
+#if __GNUC_PREREQ (3,1) || __glibc_has_attribute (__used__)
 # define __attribute_used__ __attribute__ ((__used__))
 # define __attribute_noinline__ __attribute__ ((__noinline__))
 #else
@@ -276,7 +279,7 @@
 #endif
 
 /* Since version 3.2, gcc allows marking deprecated functions.  */
-#if __GNUC_PREREQ (3,2) || __glibc_clang_has_attribute (__deprecated__)
+#if __GNUC_PREREQ (3,2) || __glibc_has_attribute (__deprecated__)
 # define __attribute_deprecated__ __attribute__ ((__deprecated__))
 #else
 # define __attribute_deprecated__ /* Ignore */
@@ -285,8 +288,8 @@
 /* Since version 4.5, gcc also allows one to specify the message printed
    when a deprecated function is used.  clang claims to be gcc 4.2, but
    may also support this feature.  */
-#if __GNUC_PREREQ (4,5) || \
-    __glibc_clang_has_extension (__attribute_deprecated_with_message__)
+#if __GNUC_PREREQ (4,5) \
+    || __glibc_has_extension (__attribute_deprecated_with_message__)
 # define __attribute_deprecated_msg__(msg) \
          __attribute__ ((__deprecated__ (msg)))
 #else
@@ -299,7 +302,7 @@
    If several `format_arg' attributes are given for the same function, in
    gcc-3.0 and older, all but the last one are ignored.  In newer gccs,
    all designated arguments are considered.  */
-#if __GNUC_PREREQ (2,8) || __glibc_clang_has_attribute (__format_arg__)
+#if __GNUC_PREREQ (2,8) || __glibc_has_attribute (__format_arg__)
 # define __attribute_format_arg__(x) __attribute__ ((__format_arg__ (x)))
 #else
 # define __attribute_format_arg__(x) /* Ignore */
@@ -309,7 +312,7 @@
    attribute for functions was introduced.  We don't want to use it
    unconditionally (although this would be possible) since it
    generates warnings.  */
-#if __GNUC_PREREQ (2,97) || __glibc_clang_has_attribute (__format__)
+#if __GNUC_PREREQ (2,97) || __glibc_has_attribute (__format__)
 # define __attribute_format_strfmon__(a,b) \
   __attribute__ ((__format__ (__strfmon__, a, b)))
 #else
@@ -317,19 +320,21 @@
 #endif
 
 /* The nonnull function attribute marks pointer parameters that
-   must not be NULL.  Do not define __nonnull if it is already defined,
-   for portability when this file is used in Gnulib.  */
+   must not be NULL.  */
 #ifndef __nonnull
-# if __GNUC_PREREQ (3,3) || __glibc_clang_has_attribute (__nonnull__)
+# if __GNUC_PREREQ (3,3) || __glibc_has_attribute (__nonnull__)
 #  define __nonnull(params) __attribute__ ((__nonnull__ params))
 # else
 #  define __nonnull(params)
 # endif
+#elif !defined __GLIBC__
+# undef __nonnull
+# define __nonnull(params) _GL_ATTRIBUTE_NONNULL (params)
 #endif
 
 /* If fortification mode, we warn about unused results of certain
    function calls which can lead to problems.  */
-#if __GNUC_PREREQ (3,4) || __glibc_clang_has_attribute (__warn_unused_result__)
+#if __GNUC_PREREQ (3,4) || __glibc_has_attribute (__warn_unused_result__)
 # define __attribute_warn_unused_result__ \
    __attribute__ ((__warn_unused_result__))
 # if defined __USE_FORTIFY_LEVEL && __USE_FORTIFY_LEVEL > 0
@@ -343,7 +348,7 @@
 #endif
 
 /* Forces a function to be always inlined.  */
-#if __GNUC_PREREQ (3,2) || __glibc_clang_has_attribute (__always_inline__)
+#if __GNUC_PREREQ (3,2) || __glibc_has_attribute (__always_inline__)
 /* The Linux kernel defines __always_inline in stddef.h (283d7573), and
    it conflicts with this definition.  Therefore undefine it first to
    allow either header to be included first.  */
@@ -356,7 +361,7 @@
 
 /* Associate error messages with the source location of the call site rather
    than with the source location inside the function.  */
-#if __GNUC_PREREQ (4,3) || __glibc_clang_has_attribute (__artificial__)
+#if __GNUC_PREREQ (4,3) || __glibc_has_attribute (__artificial__)
 # define __attribute_artificial__ __attribute__ ((__artificial__))
 #else
 # define __attribute_artificial__ /* Ignore */
@@ -433,7 +438,7 @@
 # endif
 #endif
 
-#if (__GNUC__ >= 3) || __glibc_clang_has_builtin (__builtin_expect)
+#if (__GNUC__ >= 3) || __glibc_has_builtin (__builtin_expect)
 # define __glibc_unlikely(cond) __builtin_expect ((cond), 0)
 # define __glibc_likely(cond)   __builtin_expect ((cond), 1)
 #else
@@ -441,12 +446,6 @@
 # define __glibc_likely(cond)   (cond)
 #endif
 
-#ifdef __has_attribute
-# define __glibc_has_attribute(attr)    __has_attribute (attr)
-#else
-# define __glibc_has_attribute(attr)    0
-#endif
-
 #if (!defined _Noreturn \
      && (defined __STDC_VERSION__ ? __STDC_VERSION__ : 0) < 201112 \
      &&  !(__GNUC_PREREQ (4,7) \
@@ -467,6 +466,16 @@
 # define __attribute_nonstring__
 #endif
 
+/* Undefine (also defined in libc-symbols.h).  */
+#undef __attribute_copy__
+#if __GNUC_PREREQ (9, 0)
+/* Copies attributes from the declaration or type referenced by
+   the argument.  */
+# define __attribute_copy__(arg) __attribute__ ((__copy__ (arg)))
+#else
+# define __attribute_copy__(arg)
+#endif
+
 #if (!defined _Static_assert && !defined __cplusplus \
      && (defined __STDC_VERSION__ ? __STDC_VERSION__ : 0) < 201112 \
      && (!(__GNUC_PREREQ (4, 6) || __clang_major__ >= 4) \
@@ -483,7 +492,37 @@
 # include <bits/long-double.h>
 #endif
 
-#if defined __LONG_DOUBLE_MATH_OPTIONAL && defined __NO_LONG_DOUBLE_MATH
+#if __LDOUBLE_REDIRECTS_TO_FLOAT128_ABI == 1
+# ifdef __REDIRECT
+
+/* Alias name defined automatically.  */
+#  define __LDBL_REDIR(name, proto) ... unused__ldbl_redir
+#  define __LDBL_REDIR_DECL(name) \
+  extern __typeof (name) name __asm (__ASMNAME ("__" #name "ieee128"));
+
+/* Alias name defined automatically, with leading underscores.  */
+#  define __LDBL_REDIR2_DECL(name) \
+  extern __typeof (__##name) __##name \
+    __asm (__ASMNAME ("__" #name "ieee128"));
+
+/* Alias name defined manually.  */
+#  define __LDBL_REDIR1(name, proto, alias) ... unused__ldbl_redir1
+#  define __LDBL_REDIR1_DECL(name, alias) \
+  extern __typeof (name) name __asm (__ASMNAME (#alias));
+
+#  define __LDBL_REDIR1_NTH(name, proto, alias) \
+  __REDIRECT_NTH (name, proto, alias)
+#  define __REDIRECT_NTH_LDBL(name, proto, alias) \
+  __LDBL_REDIR1_NTH (name, proto, __##alias##ieee128)
+
+/* Unused.  */
+#  define __REDIRECT_LDBL(name, proto, alias) ... unused__redirect_ldbl
+#  define __LDBL_REDIR_NTH(name, proto) ... unused__ldbl_redir_nth
+
+# else
+_Static_assert (0, "IEEE 128-bits long double requires redirection on this platform");
+# endif
+#elif defined __LONG_DOUBLE_MATH_OPTIONAL && defined __NO_LONG_DOUBLE_MATH
 # define __LDBL_COMPAT 1
 # ifdef __REDIRECT
 #  define __LDBL_REDIR1(name, proto, alias) __REDIRECT (name, proto, alias)
@@ -492,6 +531,8 @@
 #  define __LDBL_REDIR1_NTH(name, proto, alias) __REDIRECT_NTH (name, proto, alias)
 #  define __LDBL_REDIR_NTH(name, proto) \
   __LDBL_REDIR1_NTH (name, proto, __nldbl_##name)
+#  define __LDBL_REDIR2_DECL(name) \
+  extern __typeof (__##name) __##name __asm (__ASMNAME ("__nldbl___" #name));
 #  define __LDBL_REDIR1_DECL(name, alias) \
   extern __typeof (name) name __asm (__ASMNAME (#alias));
 #  define __LDBL_REDIR_DECL(name) \
@@ -502,11 +543,13 @@
   __LDBL_REDIR1_NTH (name, proto, __nldbl_##alias)
 # endif
 #endif
-#if !defined __LDBL_COMPAT || !defined __REDIRECT
+#if (!defined __LDBL_COMPAT && __LDOUBLE_REDIRECTS_TO_FLOAT128_ABI == 0) \
+    || !defined __REDIRECT
 # define __LDBL_REDIR1(name, proto, alias) name proto
 # define __LDBL_REDIR(name, proto) name proto
 # define __LDBL_REDIR1_NTH(name, proto, alias) name proto __THROW
 # define __LDBL_REDIR_NTH(name, proto) name proto __THROW
+# define __LDBL_REDIR2_DECL(name)
 # define __LDBL_REDIR_DECL(name)
 # ifdef __REDIRECT
 #  define __REDIRECT_LDBL(name, proto, alias) __REDIRECT (name, proto, alias)
@@ -537,7 +580,7 @@
    check is required to enable the use of generic selection.  */
 #if !defined __cplusplus \
     && (__GNUC_PREREQ (4, 9) \
-        || __glibc_clang_has_extension (c_generic_selections) \
+        || __glibc_has_extension (c_generic_selections) \
         || (!defined __GNUC__ && defined __STDC_VERSION__ \
             && __STDC_VERSION__ >= 201112L))
 # define __HAVE_GENERIC_SELECTION 1
@@ -545,4 +588,23 @@
 # define __HAVE_GENERIC_SELECTION 0
 #endif
 
+#if __GNUC_PREREQ (10, 0)
+/* Designates a 1-based positional argument ref-index of pointer type
+   that can be used to access size-index elements of the pointed-to
+   array according to access mode, or at least one element when
+   size-index is not provided:
+     access (access-mode, <ref-index> [, <size-index>])  */
+#define __attr_access(x) __attribute__ ((__access__ x))
+#else
+#  define __attr_access(x)
+#endif
+
+/* Specify that a function such as setjmp or vfork may return
+   twice.  */
+#if __GNUC_PREREQ (4, 1)
+# define __attribute_returns_twice__ __attribute__ ((__returns_twice__))
+#else
+# define __attribute_returns_twice__ /* Ignore.  */
+#endif
+
 #endif   /* sys/cdefs.h */
diff --git a/lib/dirent.in.h b/lib/dirent.in.h
index 2e2c5119a11..4666972b150 100644
--- a/lib/dirent.in.h
+++ b/lib/dirent.in.h
@@ -154,7 +154,8 @@ _GL_WARN_ON_USE (closedir, "closedir is not portable - "
 /* Return the file descriptor associated with the given directory stream,
    or -1 if none exists.  */
 # if @REPLACE_DIRFD@
-#  if !(defined __cplusplus && defined GNULIB_NAMESPACE)
+/* On kLIBC, dirfd() is a macro that does not work.  Undefine it.  */
+#  if !(defined __cplusplus && defined GNULIB_NAMESPACE) || defined dirfd
 #   undef dirfd
 #   define dirfd rpl_dirfd
 #  endif
diff --git a/lib/dynarray.h b/lib/dynarray.h
new file mode 100644
index 00000000000..6da3e87e55f
--- /dev/null
+++ b/lib/dynarray.h
@@ -0,0 +1,31 @@
+/* Type-safe arrays which grow dynamically.
+   Copyright 2021 Free Software Foundation, Inc.
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
+
+/* Written by Paul Eggert, 2021.  */
+
+#ifndef _GL_DYNARRAY_H
+#define _GL_DYNARRAY_H
+
+#include <libc-config.h>
+
+#define __libc_dynarray_at_failure gl_dynarray_at_failure
+#define __libc_dynarray_emplace_enlarge gl_dynarray_emplace_enlarge
+#define __libc_dynarray_finalize gl_dynarray_finalize
+#define __libc_dynarray_resize_clear gl_dynarray_resize_clear
+#define __libc_dynarray_resize gl_dynarray_resize
+#include <malloc/dynarray.h>
+
+#endif /* _GL_DYNARRAY_H */
diff --git a/lib/explicit_bzero.c b/lib/explicit_bzero.c
index feea4446c06..f50ed0875d7 100644
--- a/lib/explicit_bzero.c
+++ b/lib/explicit_bzero.c
@@ -54,11 +54,21 @@ explicit_bzero (void *s, size_t len)
   explicit_memset (s, '\0', len);
 #elif HAVE_MEMSET_S
   (void) memset_s (s, len, '\0', len);
-#else
+#elif defined __GNUC__ && !defined __clang__
   memset (s, '\0', len);
-# if defined __GNUC__ && !defined __clang__
   /* Compiler barrier.  */
   asm volatile ("" ::: "memory");
-# endif
+#elif defined __clang__
+  memset (s, '\0', len);
+  /* Compiler barrier.  */
+  /* With asm ("" ::: "memory") LLVM analyzes uses of 's' and finds that the
+     whole thing is dead and eliminates it.  Use 'g' to work around this
+     problem.  See <https://bugs.llvm.org/show_bug.cgi?id=15495#c11>.  */
+  __asm__ volatile ("" : : "g"(s) : "memory");
+#else
+  /* Invoke memset through a volatile function pointer.  This defeats compiler
+     optimizations.  */
+  void * (* const volatile volatile_memset) (void *, int, size_t) = memset;
+  (void) volatile_memset (s, '\0', len);
 #endif
 }
diff --git a/lib/fchmodat.c b/lib/fchmodat.c
index d27c0d7734a..eb6e2242fdd 100644
--- a/lib/fchmodat.c
+++ b/lib/fchmodat.c
@@ -38,6 +38,7 @@ orig_fchmodat (int dir, char const *file, mode_t mode, int flags)
 #include <fcntl.h>
 #include <stdio.h>
 #include <stdlib.h>
+#include <string.h>
 #include <unistd.h>
 
 #ifdef __osf__
@@ -63,6 +64,22 @@ orig_fchmodat (int dir, char const *file, mode_t mode, int flags)
 int
 fchmodat (int dir, char const *file, mode_t mode, int flags)
 {
+# if HAVE_NEARLY_WORKING_FCHMODAT
+  /* Correct the trailing slash handling.  */
+  size_t len = strlen (file);
+  if (len && file[len - 1] == '/')
+    {
+      struct stat st;
+      if (fstatat (dir, file, &st, flags & AT_SYMLINK_NOFOLLOW) < 0)
+        return -1;
+      if (!S_ISDIR (st.st_mode))
+        {
+          errno = ENOTDIR;
+          return -1;
+        }
+    }
+# endif
+
 # if NEED_FCHMODAT_NONSYMLINK_FIX
   if (flags == AT_SYMLINK_NOFOLLOW)
     {
diff --git a/lib/free.c b/lib/free.c
index 135c3eb16bc..5c89787aba1 100644
--- a/lib/free.c
+++ b/lib/free.c
@@ -27,7 +27,21 @@ void
 rpl_free (void *p)
 #undef free
 {
+#if defined __GNUC__ && !defined __clang__
+  /* An invalid GCC optimization
+     <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98396>
+     would optimize away the assignments in the code below, when link-time
+     optimization (LTO) is enabled.  Make the code more complicated, so that
+     GCC does not grok how to optimize it.  */
+  int err[2];
+  err[0] = errno;
+  err[1] = errno;
+  errno = 0;
+  free (p);
+  errno = err[errno == 0];
+#else
   int err = errno;
   free (p);
   errno = err;
+#endif
 }
diff --git a/lib/gnulib.mk.in b/lib/gnulib.mk.in
index c457ac61209..07736f9b8bc 100644
--- a/lib/gnulib.mk.in
+++ b/lib/gnulib.mk.in
@@ -516,6 +516,7 @@ GNULIB_SYMLINK = @GNULIB_SYMLINK@
 GNULIB_SYMLINKAT = @GNULIB_SYMLINKAT@
 GNULIB_SYSTEM_POSIX = @GNULIB_SYSTEM_POSIX@
 GNULIB_TIMEGM = @GNULIB_TIMEGM@
+GNULIB_TIMESPEC_GET = @GNULIB_TIMESPEC_GET@
 GNULIB_TIME_R = @GNULIB_TIME_R@
 GNULIB_TIME_RZ = @GNULIB_TIME_RZ@
 GNULIB_TMPFILE = @GNULIB_TMPFILE@
@@ -746,6 +747,7 @@ HAVE_SYS_SELECT_H = @HAVE_SYS_SELECT_H@
 HAVE_SYS_TIME_H = @HAVE_SYS_TIME_H@
 HAVE_SYS_TYPES_H = @HAVE_SYS_TYPES_H@
 HAVE_TIMEGM = @HAVE_TIMEGM@
+HAVE_TIMESPEC_GET = @HAVE_TIMESPEC_GET@
 HAVE_TIMEZONE_T = @HAVE_TIMEZONE_T@
 HAVE_TYPE_VOLATILE_SIG_ATOMIC_T = @HAVE_TYPE_VOLATILE_SIG_ATOMIC_T@
 HAVE_UNISTD_H = @HAVE_UNISTD_H@
@@ -949,6 +951,7 @@ REPLACE_FCNTL = @REPLACE_FCNTL@
 REPLACE_FDOPEN = @REPLACE_FDOPEN@
 REPLACE_FDOPENDIR = @REPLACE_FDOPENDIR@
 REPLACE_FFLUSH = @REPLACE_FFLUSH@
+REPLACE_FFSLL = @REPLACE_FFSLL@
 REPLACE_FOPEN = @REPLACE_FOPEN@
 REPLACE_FPRINTF = @REPLACE_FPRINTF@
 REPLACE_FPURGE = @REPLACE_FPURGE@
@@ -989,7 +992,9 @@ REPLACE_MEMCHR = @REPLACE_MEMCHR@
 REPLACE_MEMMEM = @REPLACE_MEMMEM@
 REPLACE_MKDIR = @REPLACE_MKDIR@
 REPLACE_MKFIFO = @REPLACE_MKFIFO@
+REPLACE_MKFIFOAT = @REPLACE_MKFIFOAT@
 REPLACE_MKNOD = @REPLACE_MKNOD@
+REPLACE_MKNODAT = @REPLACE_MKNODAT@
 REPLACE_MKSTEMP = @REPLACE_MKSTEMP@
 REPLACE_MKTIME = @REPLACE_MKTIME@
 REPLACE_NANOSLEEP = @REPLACE_NANOSLEEP@
@@ -1087,6 +1092,7 @@ SYSTEM_TYPE = @SYSTEM_TYPE@
 SYS_TIME_H_DEFINES_STRUCT_TIMESPEC = @SYS_TIME_H_DEFINES_STRUCT_TIMESPEC@
 TERMCAP_OBJ = @TERMCAP_OBJ@
 TIME_H_DEFINES_STRUCT_TIMESPEC = @TIME_H_DEFINES_STRUCT_TIMESPEC@
+TIME_H_DEFINES_TIME_UTC = @TIME_H_DEFINES_TIME_UTC@
 TOOLKIT_LIBW = @TOOLKIT_LIBW@
 UINT32_MAX_LT_UINTMAX_MAX = @UINT32_MAX_LT_UINTMAX_MAX@
 UINT64_MAX_EQ_ULONG_MAX = @UINT64_MAX_EQ_ULONG_MAX@
@@ -1171,6 +1177,7 @@ gl_GNULIB_ENABLED_a9786850e999ae65a836a6041e8e5ed1 = @gl_GNULIB_ENABLED_a9786850
 gl_GNULIB_ENABLED_be453cec5eecf5731a274f2de7f2db36 = @gl_GNULIB_ENABLED_be453cec5eecf5731a274f2de7f2db36@
 gl_GNULIB_ENABLED_cloexec = @gl_GNULIB_ENABLED_cloexec@
 gl_GNULIB_ENABLED_dirfd = @gl_GNULIB_ENABLED_dirfd@
+gl_GNULIB_ENABLED_dynarray = @gl_GNULIB_ENABLED_dynarray@
 gl_GNULIB_ENABLED_euidaccess = @gl_GNULIB_ENABLED_euidaccess@
 gl_GNULIB_ENABLED_getdtablesize = @gl_GNULIB_ENABLED_getdtablesize@
 gl_GNULIB_ENABLED_getgroups = @gl_GNULIB_ENABLED_getgroups@
@@ -1584,6 +1591,20 @@ EXTRA_libgnu_a_SOURCES += dup2.c
 endif
 ## end   gnulib module dup2
 
+## begin gnulib module dynarray
+ifeq (,$(OMIT_GNULIB_MODULE_dynarray))
+
+ifneq (,$(gl_GNULIB_ENABLED_dynarray))
+libgnu_a_SOURCES += malloc/dynarray_at_failure.c                 malloc/dynarray_emplace_enlarge.c                 malloc/dynarray_finalize.c                 malloc/dynarray_resize.c                 malloc/dynarray_resize_clear.c
+
+endif
+EXTRA_DIST += dynarray.h malloc/dynarray-skeleton.c malloc/dynarray.h
+
+EXTRA_libgnu_a_SOURCES += malloc/dynarray-skeleton.c
+
+endif
+## end   gnulib module dynarray
+
 ## begin gnulib module eloop-threshold
 ifeq (,$(OMIT_GNULIB_MODULE_eloop-threshold))
 
@@ -3036,6 +3057,7 @@ string.h: string.in.h $(top_builddir)/config.status $(CXXDEFS_H) $(ARG_NONNULL_H
               -e 's|@''HAVE_SIGDESCR_NP''@|$(HAVE_SIGDESCR_NP)|g' \
               -e 's|@''HAVE_DECL_STRSIGNAL''@|$(HAVE_DECL_STRSIGNAL)|g' \
               -e 's|@''HAVE_STRVERSCMP''@|$(HAVE_STRVERSCMP)|g' \
+              -e 's|@''REPLACE_FFSLL''@|$(REPLACE_FFSLL)|g' \
               -e 's|@''REPLACE_MEMCHR''@|$(REPLACE_MEMCHR)|g' \
               -e 's|@''REPLACE_MEMMEM''@|$(REPLACE_MEMMEM)|g' \
               -e 's|@''REPLACE_STPNCPY''@|$(REPLACE_STPNCPY)|g' \
@@ -3237,7 +3259,9 @@ sys/stat.h: sys_stat.in.h $(top_builddir)/config.status $(CXXDEFS_H) $(ARG_NONNU
               -e 's|@''REPLACE_LSTAT''@|$(REPLACE_LSTAT)|g' \
               -e 's|@''REPLACE_MKDIR''@|$(REPLACE_MKDIR)|g' \
               -e 's|@''REPLACE_MKFIFO''@|$(REPLACE_MKFIFO)|g' \
+              -e 's|@''REPLACE_MKFIFOAT''@|$(REPLACE_MKFIFOAT)|g' \
               -e 's|@''REPLACE_MKNOD''@|$(REPLACE_MKNOD)|g' \
+              -e 's|@''REPLACE_MKNODAT''@|$(REPLACE_MKNODAT)|g' \
               -e 's|@''REPLACE_STAT''@|$(REPLACE_STAT)|g' \
               -e 's|@''REPLACE_UTIMENSAT''@|$(REPLACE_UTIMENSAT)|g' \
               -e '/definitions of _GL_FUNCDECL_RPL/r $(CXXDEFS_H)' \
@@ -3350,6 +3374,7 @@ time.h: time.in.h $(top_builddir)/config.status $(CXXDEFS_H) $(ARG_NONNULL_H) $(
               -e 's/@''GNULIB_STRFTIME''@/$(GNULIB_STRFTIME)/g' \
               -e 's/@''GNULIB_STRPTIME''@/$(GNULIB_STRPTIME)/g' \
               -e 's/@''GNULIB_TIMEGM''@/$(GNULIB_TIMEGM)/g' \
+              -e 's/@''GNULIB_TIMESPEC_GET''@/$(GNULIB_TIMESPEC_GET)/g' \
               -e 's/@''GNULIB_TIME_R''@/$(GNULIB_TIME_R)/g' \
               -e 's/@''GNULIB_TIME_RZ''@/$(GNULIB_TIME_RZ)/g' \
               -e 's/@''GNULIB_TZSET''@/$(GNULIB_TZSET)/g' \
@@ -3358,6 +3383,7 @@ time.h: time.in.h $(top_builddir)/config.status $(CXXDEFS_H) $(ARG_NONNULL_H) $(
               -e 's|@''HAVE_NANOSLEEP''@|$(HAVE_NANOSLEEP)|g' \
               -e 's|@''HAVE_STRPTIME''@|$(HAVE_STRPTIME)|g' \
               -e 's|@''HAVE_TIMEGM''@|$(HAVE_TIMEGM)|g' \
+              -e 's|@''HAVE_TIMESPEC_GET''@|$(HAVE_TIMESPEC_GET)|g' \
               -e 's|@''HAVE_TIMEZONE_T''@|$(HAVE_TIMEZONE_T)|g' \
               -e 's|@''REPLACE_CTIME''@|$(REPLACE_CTIME)|g' \
               -e 's|@''REPLACE_GMTIME''@|$(REPLACE_GMTIME)|g' \
@@ -3372,6 +3398,7 @@ time.h: time.in.h $(top_builddir)/config.status $(CXXDEFS_H) $(ARG_NONNULL_H) $(
               -e 's|@''SYS_TIME_H_DEFINES_STRUCT_TIMESPEC''@|$(SYS_TIME_H_DEFINES_STRUCT_TIMESPEC)|g' \
               -e 's|@''TIME_H_DEFINES_STRUCT_TIMESPEC''@|$(TIME_H_DEFINES_STRUCT_TIMESPEC)|g' \
               -e 's|@''UNISTD_H_DEFINES_STRUCT_TIMESPEC''@|$(UNISTD_H_DEFINES_STRUCT_TIMESPEC)|g' \
+              -e 's|@''TIME_H_DEFINES_TIME_UTC''@|$(TIME_H_DEFINES_TIME_UTC)|g' \
               -e '/definitions of _GL_FUNCDECL_RPL/r $(CXXDEFS_H)' \
               -e '/definition of _GL_ARG_NONNULL/r $(ARG_NONNULL_H)' \
               -e '/definition of _GL_WARN_ON_USE/r $(WARN_ON_USE_H)' \
diff --git a/lib/libc-config.h b/lib/libc-config.h
index d4e29951f35..c0eac707cfd 100644
--- a/lib/libc-config.h
+++ b/lib/libc-config.h
@@ -71,107 +71,112 @@
 # endif
 #endif
 
-
-/* Prepare to include <cdefs.h>, which is our copy of glibc
-   <sys/cdefs.h>.  */
+#ifndef __attribute_maybe_unused__
+/* <sys/cdefs.h> either does not exist, or is too old for Gnulib.
+   Prepare to include <cdefs.h>, which is Gnulib's version of a
+   more-recent glibc <sys/cdefs.h>.  */
 
 /* Define _FEATURES_H so that <cdefs.h> does not include <features.h>.  */
-#ifndef _FEATURES_H
-# define _FEATURES_H 1
-#endif
+# ifndef _FEATURES_H
+#  define _FEATURES_H 1
+# endif
 /* Define __WORDSIZE so that <cdefs.h> does not attempt to include
    nonexistent files.  Make it a syntax error, since Gnulib does not
    use __WORDSIZE now, and if Gnulib uses it later the syntax error
    will let us know that __WORDSIZE needs configuring.  */
-#ifndef __WORDSIZE
-# define __WORDSIZE %%%
-#endif
+# ifndef __WORDSIZE
+#  define __WORDSIZE %%%
+# endif
 /* Undef the macros unconditionally defined by our copy of glibc
    <sys/cdefs.h>, so that they do not clash with any system-defined
    versions.  */
-#undef _SYS_CDEFS_H
-#undef __ASMNAME
-#undef __ASMNAME2
-#undef __BEGIN_DECLS
-#undef __CONCAT
-#undef __END_DECLS
-#undef __HAVE_GENERIC_SELECTION
-#undef __LDBL_COMPAT
-#undef __LDBL_REDIR
-#undef __LDBL_REDIR1
-#undef __LDBL_REDIR1_DECL
-#undef __LDBL_REDIR1_NTH
-#undef __LDBL_REDIR_DECL
-#undef __LDBL_REDIR_NTH
-#undef __LEAF
-#undef __LEAF_ATTR
-#undef __NTH
-#undef __NTHNL
-#undef __P
-#undef __PMT
-#undef __REDIRECT
-#undef __REDIRECT_LDBL
-#undef __REDIRECT_NTH
-#undef __REDIRECT_NTHNL
-#undef __REDIRECT_NTH_LDBL
-#undef __STRING
-#undef __THROW
-#undef __THROWNL
-#undef __always_inline
-#undef __attribute__
-#undef __attribute_alloc_size__
-#undef __attribute_artificial__
-#undef __attribute_const__
-#undef __attribute_deprecated__
-#undef __attribute_deprecated_msg__
-#undef __attribute_format_arg__
-#undef __attribute_format_strfmon__
-#undef __attribute_malloc__
-#undef __attribute_noinline__
-#undef __attribute_nonstring__
-#undef __attribute_pure__
-#undef __attribute_used__
-#undef __attribute_warn_unused_result__
-#undef __bos
-#undef __bos0
-#undef __errordecl
-#undef __extension__
-#undef __extern_always_inline
-#undef __extern_inline
-#undef __flexarr
-#undef __fortify_function
-#undef __glibc_c99_flexarr_available
-#undef __glibc_clang_has_extension
-#undef __glibc_likely
-#undef __glibc_macro_warning
-#undef __glibc_macro_warning1
-#undef __glibc_unlikely
-#undef __inline
-#undef __ptr_t
-#undef __restrict
-#undef __restrict_arr
-#undef __va_arg_pack
-#undef __va_arg_pack_len
-#undef __warnattr
-#undef __warndecl
+# undef _SYS_CDEFS_H
+# undef __ASMNAME
+# undef __ASMNAME2
+# undef __BEGIN_DECLS
+# undef __CONCAT
+# undef __END_DECLS
+# undef __HAVE_GENERIC_SELECTION
+# undef __LDBL_COMPAT
+# undef __LDBL_REDIR
+# undef __LDBL_REDIR1
+# undef __LDBL_REDIR1_DECL
+# undef __LDBL_REDIR1_NTH
+# undef __LDBL_REDIR2_DECL
+# undef __LDBL_REDIR_DECL
+# undef __LDBL_REDIR_NTH
+# undef __LEAF
+# undef __LEAF_ATTR
+# undef __NTH
+# undef __NTHNL
+# undef __REDIRECT
+# undef __REDIRECT_LDBL
+# undef __REDIRECT_NTH
+# undef __REDIRECT_NTHNL
+# undef __REDIRECT_NTH_LDBL
+# undef __STRING
+# undef __THROW
+# undef __THROWNL
+# undef __attr_access
+# undef __attribute__
+# undef __attribute_alloc_size__
+# undef __attribute_artificial__
+# undef __attribute_const__
+# undef __attribute_deprecated__
+# undef __attribute_deprecated_msg__
+# undef __attribute_format_arg__
+# undef __attribute_format_strfmon__
+# undef __attribute_malloc__
+# undef __attribute_noinline__
+# undef __attribute_nonstring__
+# undef __attribute_pure__
+# undef __attribute_returns_twice__
+# undef __attribute_used__
+# undef __attribute_warn_unused_result__
+# undef __bos
+# undef __bos0
+# undef __errordecl
+# undef __extension__
+# undef __extern_always_inline
+# undef __extern_inline
+# undef __flexarr
+# undef __fortify_function
+# undef __glibc_c99_flexarr_available
+# undef __glibc_has_attribute
+# undef __glibc_has_builtin
+# undef __glibc_has_extension
+# undef __glibc_macro_warning
+# undef __glibc_macro_warning1
+# undef __glibc_objsize
+# undef __glibc_objsize0
+# undef __glibc_unlikely
+# undef __inline
+# undef __ptr_t
+# undef __restrict
+# undef __restrict_arr
+# undef __va_arg_pack
+# undef __va_arg_pack_len
+# undef __warnattr
 
 /* Include our copy of glibc <sys/cdefs.h>.  */
-#include <cdefs.h>
+# include <cdefs.h>
 
 /* <cdefs.h> __inline is too pessimistic for non-GCC.  */
-#undef __inline
-#ifndef HAVE___INLINE
-# if 199901 <= __STDC_VERSION__ || defined inline
-#  define __inline inline
-# else
-#  define __inline
+# undef __inline
+# ifndef HAVE___INLINE
+#  if 199901 <= __STDC_VERSION__ || defined inline
+#   define __inline inline
+#  else
+#   define __inline
+#  endif
 # endif
-#endif
+
+#endif /* defined __glibc_likely */
 
 
 /* A substitute for glibc <libc-symbols.h>, good enough for Gnulib.  */
 #define attribute_hidden
-#define libc_hidden_proto(name, ...)
+#define libc_hidden_proto(name)
 #define libc_hidden_def(name)
 #define libc_hidden_weak(name)
 #define libc_hidden_ver(local, name)
diff --git a/lib/malloc/dynarray-skeleton.c b/lib/malloc/dynarray-skeleton.c
new file mode 100644
index 00000000000..4995fd1c049
--- /dev/null
+++ b/lib/malloc/dynarray-skeleton.c
@@ -0,0 +1,525 @@
+/* Type-safe arrays which grow dynamically.
+   Copyright (C) 2017-2021 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU General Public
+   License as published by the Free Software Foundation; either
+   version 3 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   General Public License for more details.
+
+   You should have received a copy of the GNU General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+/* Pre-processor macros which act as parameters:
+
+   DYNARRAY_STRUCT
+      The struct tag of dynamic array to be defined.
+   DYNARRAY_ELEMENT
+      The type name of the element type.  Elements are copied
+      as if by memcpy, and can change address as the dynamic
+      array grows.
+   DYNARRAY_PREFIX
+      The prefix of the functions which are defined.
+
+   The following parameters are optional:
+
+   DYNARRAY_ELEMENT_FREE
+      DYNARRAY_ELEMENT_FREE (E) is evaluated to deallocate the
+      contents of elements. E is of type  DYNARRAY_ELEMENT *.
+   DYNARRAY_ELEMENT_INIT
+      DYNARRAY_ELEMENT_INIT (E) is evaluated to initialize a new
+      element.  E is of type  DYNARRAY_ELEMENT *.
+      If DYNARRAY_ELEMENT_FREE but not DYNARRAY_ELEMENT_INIT is
+      defined, new elements are automatically zero-initialized.
+      Otherwise, new elements have undefined contents.
+   DYNARRAY_INITIAL_SIZE
+      The size of the statically allocated array (default:
+      at least 2, more elements if they fit into 128 bytes).
+      Must be a preprocessor constant.  If DYNARRAY_INITIAL_SIZE is 0,
+      there is no statically allocated array at, and all non-empty
+      arrays are heap-allocated.
+   DYNARRAY_FINAL_TYPE
+      The name of the type which holds the final array.  If not
+      defined, is PREFIX##finalize not provided.  DYNARRAY_FINAL_TYPE
+      must be a struct type, with members of type DYNARRAY_ELEMENT and
+      size_t at the start (in this order).
+
+   These macros are undefined after this header file has been
+   included.
+
+   The following types are provided (their members are private to the
+   dynarray implementation):
+
+     struct DYNARRAY_STRUCT
+
+   The following functions are provided:
+
+     void DYNARRAY_PREFIX##init (struct DYNARRAY_STRUCT *);
+     void DYNARRAY_PREFIX##free (struct DYNARRAY_STRUCT *);
+     bool DYNARRAY_PREFIX##has_failed (const struct DYNARRAY_STRUCT *);
+     void DYNARRAY_PREFIX##mark_failed (struct DYNARRAY_STRUCT *);
+     size_t DYNARRAY_PREFIX##size (const struct DYNARRAY_STRUCT *);
+     DYNARRAY_ELEMENT *DYNARRAY_PREFIX##begin (const struct DYNARRAY_STRUCT *);
+     DYNARRAY_ELEMENT *DYNARRAY_PREFIX##end (const struct DYNARRAY_STRUCT *);
+     DYNARRAY_ELEMENT *DYNARRAY_PREFIX##at (struct DYNARRAY_STRUCT *, size_t);
+     void DYNARRAY_PREFIX##add (struct DYNARRAY_STRUCT *, DYNARRAY_ELEMENT);
+     DYNARRAY_ELEMENT *DYNARRAY_PREFIX##emplace (struct DYNARRAY_STRUCT *);
+     bool DYNARRAY_PREFIX##resize (struct DYNARRAY_STRUCT *, size_t);
+     void DYNARRAY_PREFIX##remove_last (struct DYNARRAY_STRUCT *);
+     void DYNARRAY_PREFIX##clear (struct DYNARRAY_STRUCT *);
+
+   The following functions are provided are provided if the
+   prerequisites are met:
+
+     bool DYNARRAY_PREFIX##finalize (struct DYNARRAY_STRUCT *,
+                                     DYNARRAY_FINAL_TYPE *);
+       (if DYNARRAY_FINAL_TYPE is defined)
+     DYNARRAY_ELEMENT *DYNARRAY_PREFIX##finalize (struct DYNARRAY_STRUCT *,
+                                                  size_t *);
+       (if DYNARRAY_FINAL_TYPE is not defined)
+*/
+
+#include <malloc/dynarray.h>
+
+#include <errno.h>
+#include <stdlib.h>
+#include <string.h>
+
+#ifndef DYNARRAY_STRUCT
+# error "DYNARRAY_STRUCT must be defined"
+#endif
+
+#ifndef DYNARRAY_ELEMENT
+# error "DYNARRAY_ELEMENT must be defined"
+#endif
+
+#ifndef DYNARRAY_PREFIX
+# error "DYNARRAY_PREFIX must be defined"
+#endif
+
+#ifdef DYNARRAY_INITIAL_SIZE
+# if DYNARRAY_INITIAL_SIZE < 0
+#  error "DYNARRAY_INITIAL_SIZE must be non-negative"
+# endif
+# if DYNARRAY_INITIAL_SIZE > 0
+#  define DYNARRAY_HAVE_SCRATCH 1
+# else
+#  define DYNARRAY_HAVE_SCRATCH 0
+# endif
+#else
+/* Provide a reasonable default which limits the size of
+   DYNARRAY_STRUCT.  */
+# define DYNARRAY_INITIAL_SIZE \
+  (sizeof (DYNARRAY_ELEMENT) > 64 ? 2 : 128 / sizeof (DYNARRAY_ELEMENT))
+# define DYNARRAY_HAVE_SCRATCH 1
+#endif
+
+/* Public type definitions.  */
+
+/* All fields of this struct are private to the implementation.  */
+struct DYNARRAY_STRUCT
+{
+  union
+  {
+    struct dynarray_header dynarray_abstract;
+    struct
+    {
+      /* These fields must match struct dynarray_header.  */
+      size_t used;
+      size_t allocated;
+      DYNARRAY_ELEMENT *array;
+    } dynarray_header;
+  } u;
+
+#if DYNARRAY_HAVE_SCRATCH
+  /* Initial inline allocation.  */
+  DYNARRAY_ELEMENT scratch[DYNARRAY_INITIAL_SIZE];
+#endif
+};
+
+/* Internal use only: Helper macros.  */
+
+/* Ensure macro-expansion of DYNARRAY_PREFIX.  */
+#define DYNARRAY_CONCAT0(prefix, name) prefix##name
+#define DYNARRAY_CONCAT1(prefix, name) DYNARRAY_CONCAT0(prefix, name)
+#define DYNARRAY_NAME(name) DYNARRAY_CONCAT1(DYNARRAY_PREFIX, name)
+
+/* Use DYNARRAY_FREE instead of DYNARRAY_NAME (free),
+   so that Gnulib does not change 'free' to 'rpl_free'.  */
+#define DYNARRAY_FREE DYNARRAY_CONCAT1 (DYNARRAY_NAME (f), ree)
+
+/* Address of the scratch buffer if any.  */
+#if DYNARRAY_HAVE_SCRATCH
+# define DYNARRAY_SCRATCH(list) (list)->scratch
+#else
+# define DYNARRAY_SCRATCH(list) NULL
+#endif
+
+/* Internal use only: Helper functions.  */
+
+/* Internal function.  Call DYNARRAY_ELEMENT_FREE with the array
+   elements.  Name mangling needed due to the DYNARRAY_ELEMENT_FREE
+   macro expansion.  */
+static inline void
+DYNARRAY_NAME (free__elements__) (DYNARRAY_ELEMENT *__dynarray_array,
+                                  size_t __dynarray_used)
+{
+#ifdef DYNARRAY_ELEMENT_FREE
+  for (size_t __dynarray_i = 0; __dynarray_i < __dynarray_used; ++__dynarray_i)
+    DYNARRAY_ELEMENT_FREE (&__dynarray_array[__dynarray_i]);
+#endif /* DYNARRAY_ELEMENT_FREE */
+}
+
+/* Internal function.  Free the non-scratch array allocation.  */
+static inline void
+DYNARRAY_NAME (free__array__) (struct DYNARRAY_STRUCT *list)
+{
+#if DYNARRAY_HAVE_SCRATCH
+  if (list->u.dynarray_header.array != list->scratch)
+    free (list->u.dynarray_header.array);
+#else
+  free (list->u.dynarray_header.array);
+#endif
+}
+
+/* Public functions.  */
+
+/* Initialize a dynamic array object.  This must be called before any
+   use of the object.  */
+__nonnull ((1))
+static void
+DYNARRAY_NAME (init) (struct DYNARRAY_STRUCT *list)
+{
+  list->u.dynarray_header.used = 0;
+  list->u.dynarray_header.allocated = DYNARRAY_INITIAL_SIZE;
+  list->u.dynarray_header.array = DYNARRAY_SCRATCH (list);
+}
+
+/* Deallocate the dynamic array and its elements.  */
+__attribute_maybe_unused__ __nonnull ((1))
+static void
+DYNARRAY_FREE (struct DYNARRAY_STRUCT *list)
+{
+  DYNARRAY_NAME (free__elements__)
+    (list->u.dynarray_header.array, list->u.dynarray_header.used);
+  DYNARRAY_NAME (free__array__) (list);
+  DYNARRAY_NAME (init) (list);
+}
+
+/* Return true if the dynamic array is in an error state.  */
+__nonnull ((1))
+static inline bool
+DYNARRAY_NAME (has_failed) (const struct DYNARRAY_STRUCT *list)
+{
+  return list->u.dynarray_header.allocated == __dynarray_error_marker ();
+}
+
+/* Mark the dynamic array as failed.  All elements are deallocated as
+   a side effect.  */
+__nonnull ((1))
+static void
+DYNARRAY_NAME (mark_failed) (struct DYNARRAY_STRUCT *list)
+{
+  DYNARRAY_NAME (free__elements__)
+    (list->u.dynarray_header.array, list->u.dynarray_header.used);
+  DYNARRAY_NAME (free__array__) (list);
+  list->u.dynarray_header.array = DYNARRAY_SCRATCH (list);
+  list->u.dynarray_header.used = 0;
+  list->u.dynarray_header.allocated = __dynarray_error_marker ();
+}
+
+/* Return the number of elements which have been added to the dynamic
+   array.  */
+__nonnull ((1))
+static inline size_t
+DYNARRAY_NAME (size) (const struct DYNARRAY_STRUCT *list)
+{
+  return list->u.dynarray_header.used;
+}
+
+/* Return a pointer to the array element at INDEX.  Terminate the
+   process if INDEX is out of bounds.  */
+__nonnull ((1))
+static inline DYNARRAY_ELEMENT *
+DYNARRAY_NAME (at) (struct DYNARRAY_STRUCT *list, size_t index)
+{
+  if (__glibc_unlikely (index >= DYNARRAY_NAME (size) (list)))
+    __libc_dynarray_at_failure (DYNARRAY_NAME (size) (list), index);
+  return list->u.dynarray_header.array + index;
+}
+
+/* Return a pointer to the first array element, if any.  For a
+   zero-length array, the pointer can be NULL even though the dynamic
+   array has not entered the failure state.  */
+__nonnull ((1))
+static inline DYNARRAY_ELEMENT *
+DYNARRAY_NAME (begin) (struct DYNARRAY_STRUCT *list)
+{
+  return list->u.dynarray_header.array;
+}
+
+/* Return a pointer one element past the last array element.  For a
+   zero-length array, the pointer can be NULL even though the dynamic
+   array has not entered the failure state.  */
+__nonnull ((1))
+static inline DYNARRAY_ELEMENT *
+DYNARRAY_NAME (end) (struct DYNARRAY_STRUCT *list)
+{
+  return list->u.dynarray_header.array + list->u.dynarray_header.used;
+}
+
+/* Internal function.  Slow path for the add function below.  */
+static void
+DYNARRAY_NAME (add__) (struct DYNARRAY_STRUCT *list, DYNARRAY_ELEMENT item)
+{
+  if (__glibc_unlikely
+      (!__libc_dynarray_emplace_enlarge (&list->u.dynarray_abstract,
+                                         DYNARRAY_SCRATCH (list),
+                                         sizeof (DYNARRAY_ELEMENT))))
+    {
+      DYNARRAY_NAME (mark_failed) (list);
+      return;
+    }
+
+  /* Copy the new element and increase the array length.  */
+  list->u.dynarray_header.array[list->u.dynarray_header.used++] = item;
+}
+
+/* Add ITEM at the end of the array, enlarging it by one element.
+   Mark *LIST as failed if the dynamic array allocation size cannot be
+   increased.  */
+__nonnull ((1))
+static inline void
+DYNARRAY_NAME (add) (struct DYNARRAY_STRUCT *list, DYNARRAY_ELEMENT item)
+{
+  /* Do nothing in case of previous error.  */
+  if (DYNARRAY_NAME (has_failed) (list))
+    return;
+
+  /* Enlarge the array if necessary.  */
+  if (__glibc_unlikely (list->u.dynarray_header.used
+                        == list->u.dynarray_header.allocated))
+    {
+      DYNARRAY_NAME (add__) (list, item);
+      return;
+    }
+
+  /* Copy the new element and increase the array length.  */
+  list->u.dynarray_header.array[list->u.dynarray_header.used++] = item;
+}
+
+/* Internal function.  Building block for the emplace functions below.
+   Assumes space for one more element in *LIST.  */
+static inline DYNARRAY_ELEMENT *
+DYNARRAY_NAME (emplace__tail__) (struct DYNARRAY_STRUCT *list)
+{
+  DYNARRAY_ELEMENT *result
+    = &list->u.dynarray_header.array[list->u.dynarray_header.used];
+  ++list->u.dynarray_header.used;
+#if defined (DYNARRAY_ELEMENT_INIT)
+  DYNARRAY_ELEMENT_INIT (result);
+#elif defined (DYNARRAY_ELEMENT_FREE)
+  memset (result, 0, sizeof (*result));
+#endif
+  return result;
+}
+
+/* Internal function.  Slow path for the emplace function below.  */
+static DYNARRAY_ELEMENT *
+DYNARRAY_NAME (emplace__) (struct DYNARRAY_STRUCT *list)
+{
+  if (__glibc_unlikely
+      (!__libc_dynarray_emplace_enlarge (&list->u.dynarray_abstract,
+                                         DYNARRAY_SCRATCH (list),
+                                         sizeof (DYNARRAY_ELEMENT))))
+    {
+      DYNARRAY_NAME (mark_failed) (list);
+      return NULL;
+    }
+  return DYNARRAY_NAME (emplace__tail__) (list);
+}
+
+/* Allocate a place for a new element in *LIST and return a pointer to
+   it.  The pointer can be NULL if the dynamic array cannot be
+   enlarged due to a memory allocation failure.  */
+__attribute_maybe_unused__ __attribute_warn_unused_result__ __nonnull ((1))
+static
+/* Avoid inlining with the larger initialization code.  */
+#if !(defined (DYNARRAY_ELEMENT_INIT) || defined (DYNARRAY_ELEMENT_FREE))
+inline
+#endif
+DYNARRAY_ELEMENT *
+DYNARRAY_NAME (emplace) (struct DYNARRAY_STRUCT *list)
+{
+  /* Do nothing in case of previous error.  */
+  if (DYNARRAY_NAME (has_failed) (list))
+    return NULL;
+
+  /* Enlarge the array if necessary.  */
+  if (__glibc_unlikely (list->u.dynarray_header.used
+                        == list->u.dynarray_header.allocated))
+    return (DYNARRAY_NAME (emplace__) (list));
+  return DYNARRAY_NAME (emplace__tail__) (list);
+}
+
+/* Change the size of *LIST to SIZE.  If SIZE is larger than the
+   existing size, new elements are added (which can be initialized).
+   Otherwise, the list is truncated, and elements are freed.  Return
+   false on memory allocation failure (and mark *LIST as failed).  */
+__attribute_maybe_unused__ __nonnull ((1))
+static bool
+DYNARRAY_NAME (resize) (struct DYNARRAY_STRUCT *list, size_t size)
+{
+  if (size > list->u.dynarray_header.used)
+    {
+      bool ok;
+#if defined (DYNARRAY_ELEMENT_INIT)
+      /* The new elements have to be initialized.  */
+      size_t old_size = list->u.dynarray_header.used;
+      ok = __libc_dynarray_resize (&list->u.dynarray_abstract,
+                                   size, DYNARRAY_SCRATCH (list),
+                                   sizeof (DYNARRAY_ELEMENT));
+      if (ok)
+        for (size_t i = old_size; i < size; ++i)
+          {
+            DYNARRAY_ELEMENT_INIT (&list->u.dynarray_header.array[i]);
+          }
+#elif defined (DYNARRAY_ELEMENT_FREE)
+      /* Zero initialization is needed so that the elements can be
+         safely freed.  */
+      ok = __libc_dynarray_resize_clear
+        (&list->u.dynarray_abstract, size,
+         DYNARRAY_SCRATCH (list), sizeof (DYNARRAY_ELEMENT));
+#else
+      ok =  __libc_dynarray_resize (&list->u.dynarray_abstract,
+                                    size, DYNARRAY_SCRATCH (list),
+                                    sizeof (DYNARRAY_ELEMENT));
+#endif
+      if (__glibc_unlikely (!ok))
+        DYNARRAY_NAME (mark_failed) (list);
+      return ok;
+    }
+  else
+    {
+      /* The list has shrunk in size.  Free the removed elements.  */
+      DYNARRAY_NAME (free__elements__)
+        (list->u.dynarray_header.array + size,
+         list->u.dynarray_header.used - size);
+      list->u.dynarray_header.used = size;
+      return true;
+    }
+}
+
+/* Remove the last element of LIST if it is present.  */
+__attribute_maybe_unused__ __nonnull ((1))
+static void
+DYNARRAY_NAME (remove_last) (struct DYNARRAY_STRUCT *list)
+{
+  /* used > 0 implies that the array is the non-failed state.  */
+  if (list->u.dynarray_header.used > 0)
+    {
+      size_t new_length = list->u.dynarray_header.used - 1;
+#ifdef DYNARRAY_ELEMENT_FREE
+      DYNARRAY_ELEMENT_FREE (&list->u.dynarray_header.array[new_length]);
+#endif
+      list->u.dynarray_header.used = new_length;
+    }
+}
+
+/* Remove all elements from the list.  The elements are freed, but the
+   list itself is not.  */
+__attribute_maybe_unused__ __nonnull ((1))
+static void
+DYNARRAY_NAME (clear) (struct DYNARRAY_STRUCT *list)
+{
+  /* free__elements__ does nothing if the list is in the failed
+     state.  */
+  DYNARRAY_NAME (free__elements__)
+    (list->u.dynarray_header.array, list->u.dynarray_header.used);
+  list->u.dynarray_header.used = 0;
+}
+
+#ifdef DYNARRAY_FINAL_TYPE
+/* Transfer the dynamic array to a permanent location at *RESULT.
+   Returns true on success on false on allocation failure.  In either
+   case, *LIST is re-initialized and can be reused.  A NULL pointer is
+   stored in *RESULT if LIST refers to an empty list.  On success, the
+   pointer in *RESULT is heap-allocated and must be deallocated using
+   free.  */
+__attribute_maybe_unused__ __attribute_warn_unused_result__ __nonnull ((1, 2))
+static bool
+DYNARRAY_NAME (finalize) (struct DYNARRAY_STRUCT *list,
+                          DYNARRAY_FINAL_TYPE *result)
+{
+  struct dynarray_finalize_result res;
+  if (__libc_dynarray_finalize (&list->u.dynarray_abstract,
+                                DYNARRAY_SCRATCH (list),
+                                sizeof (DYNARRAY_ELEMENT), &res))
+    {
+      /* On success, the result owns all the data.  */
+      DYNARRAY_NAME (init) (list);
+      *result = (DYNARRAY_FINAL_TYPE) { res.array, res.length };
+      return true;
+    }
+  else
+    {
+      /* On error, we need to free all data.  */
+      DYNARRAY_FREE (list);
+      errno = ENOMEM;
+      return false;
+    }
+}
+#else /* !DYNARRAY_FINAL_TYPE */
+/* Transfer the dynamic array to a heap-allocated array and return a
+   pointer to it.  The pointer is NULL if memory allocation fails, or
+   if the array is empty, so this function should be used only for
+   arrays which are known not be empty (usually because they always
+   have a sentinel at the end).  If LENGTHP is not NULL, the array
+   length is written to *LENGTHP.  *LIST is re-initialized and can be
+   reused.  */
+__attribute_maybe_unused__ __attribute_warn_unused_result__ __nonnull ((1))
+static DYNARRAY_ELEMENT *
+DYNARRAY_NAME (finalize) (struct DYNARRAY_STRUCT *list, size_t *lengthp)
+{
+  struct dynarray_finalize_result res;
+  if (__libc_dynarray_finalize (&list->u.dynarray_abstract,
+                                DYNARRAY_SCRATCH (list),
+                                sizeof (DYNARRAY_ELEMENT), &res))
+    {
+      /* On success, the result owns all the data.  */
+      DYNARRAY_NAME (init) (list);
+      if (lengthp != NULL)
+        *lengthp = res.length;
+      return res.array;
+    }
+  else
+    {
+      /* On error, we need to free all data.  */
+      DYNARRAY_FREE (list);
+      errno = ENOMEM;
+      return NULL;
+    }
+}
+#endif /* !DYNARRAY_FINAL_TYPE */
+
+/* Undo macro definitions.  */
+
+#undef DYNARRAY_CONCAT0
+#undef DYNARRAY_CONCAT1
+#undef DYNARRAY_NAME
+#undef DYNARRAY_SCRATCH
+#undef DYNARRAY_HAVE_SCRATCH
+
+#undef DYNARRAY_STRUCT
+#undef DYNARRAY_ELEMENT
+#undef DYNARRAY_PREFIX
+#undef DYNARRAY_ELEMENT_FREE
+#undef DYNARRAY_ELEMENT_INIT
+#undef DYNARRAY_INITIAL_SIZE
+#undef DYNARRAY_FINAL_TYPE
diff --git a/lib/malloc/dynarray.h b/lib/malloc/dynarray.h
new file mode 100644
index 00000000000..84e4394bf32
--- /dev/null
+++ b/lib/malloc/dynarray.h
@@ -0,0 +1,178 @@
+/* Type-safe arrays which grow dynamically.  Shared definitions.
+   Copyright (C) 2017-2021 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU General Public
+   License as published by the Free Software Foundation; either
+   version 3 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   General Public License for more details.
+
+   You should have received a copy of the GNU General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+/* To use the dynarray facility, you need to include
+   <malloc/dynarray-skeleton.c> and define the parameter macros
+   documented in that file.
+
+   A minimal example which provides a growing list of integers can be
+   defined like this:
+
+     struct int_array
+     {
+       // Pointer to result array followed by its length,
+       // as required by DYNARRAY_FINAL_TYPE.
+       int *array;
+       size_t length;
+     };
+
+     #define DYNARRAY_STRUCT dynarray_int
+     #define DYNARRAY_ELEMENT int
+     #define DYNARRAY_PREFIX dynarray_int_
+     #define DYNARRAY_FINAL_TYPE struct int_array
+     #include <malloc/dynarray-skeleton.c>
+
+   To create a three-element array with elements 1, 2, 3, use this
+   code:
+
+     struct dynarray_int dyn;
+     dynarray_int_init (&dyn);
+     for (int i = 1; i <= 3; ++i)
+       {
+         int *place = dynarray_int_emplace (&dyn);
+         assert (place != NULL);
+         *place = i;
+       }
+     struct int_array result;
+     bool ok = dynarray_int_finalize (&dyn, &result);
+     assert (ok);
+     assert (result.length == 3);
+     assert (result.array[0] == 1);
+     assert (result.array[1] == 2);
+     assert (result.array[2] == 3);
+     free (result.array);
+
+   If the elements contain resources which must be freed, define
+   DYNARRAY_ELEMENT_FREE appropriately, like this:
+
+     struct str_array
+     {
+       char **array;
+       size_t length;
+     };
+
+     #define DYNARRAY_STRUCT dynarray_str
+     #define DYNARRAY_ELEMENT char *
+     #define DYNARRAY_ELEMENT_FREE(ptr) free (*ptr)
+     #define DYNARRAY_PREFIX dynarray_str_
+     #define DYNARRAY_FINAL_TYPE struct str_array
+     #include <malloc/dynarray-skeleton.c>
+
+   Compared to scratch buffers, dynamic arrays have the following
+   features:
+
+   - They have an element type, and are not just an untyped buffer of
+     bytes.
+
+   - When growing, previously stored elements are preserved.  (It is
+     expected that scratch_buffer_grow_preserve and
+     scratch_buffer_set_array_size eventually go away because all
+     current users are moved to dynamic arrays.)
+
+   - Scratch buffers have a more aggressive growth policy because
+     growing them typically means a retry of an operation (across an
+     NSS service module boundary), which is expensive.
+
+   - For the same reason, scratch buffers have a much larger initial
+     stack allocation.  */
+
+#ifndef _DYNARRAY_H
+#define _DYNARRAY_H
+
+#include <stdbool.h>
+#include <stddef.h>
+#include <string.h>
+
+struct dynarray_header
+{
+  size_t used;
+  size_t allocated;
+  void *array;
+};
+
+/* Marker used in the allocated member to indicate that an error was
+   encountered.  */
+static inline size_t
+__dynarray_error_marker (void)
+{
+  return -1;
+}
+
+/* Internal function.  See the has_failed function in
+   dynarray-skeleton.c.  */
+static inline bool
+__dynarray_error (struct dynarray_header *list)
+{
+  return list->allocated == __dynarray_error_marker ();
+}
+
+/* Internal function.  Enlarge the dynamically allocated area of the
+   array to make room for one more element.  SCRATCH is a pointer to
+   the scratch area (which is not heap-allocated and must not be
+   freed).  ELEMENT_SIZE is the size, in bytes, of one element.
+   Return false on failure, true on success.  */
+bool __libc_dynarray_emplace_enlarge (struct dynarray_header *,
+                                      void *scratch, size_t element_size);
+
+/* Internal function.  Enlarge the dynamically allocated area of the
+   array to make room for at least SIZE elements (which must be larger
+   than the existing used part of the dynamic array).  SCRATCH is a
+   pointer to the scratch area (which is not heap-allocated and must
+   not be freed).  ELEMENT_SIZE is the size, in bytes, of one element.
+   Return false on failure, true on success.  */
+bool __libc_dynarray_resize (struct dynarray_header *, size_t size,
+                             void *scratch, size_t element_size);
+
+/* Internal function.  Like __libc_dynarray_resize, but clear the new
+   part of the dynamic array.  */
+bool __libc_dynarray_resize_clear (struct dynarray_header *, size_t size,
+                                   void *scratch, size_t element_size);
+
+/* Internal type.  */
+struct dynarray_finalize_result
+{
+  void *array;
+  size_t length;
+};
+
+/* Internal function.  Copy the dynamically-allocated area to an
+   explicitly-sized heap allocation.  SCRATCH is a pointer to the
+   embedded scratch space.  ELEMENT_SIZE is the size, in bytes, of the
+   element type.  On success, true is returned, and pointer and length
+   are written to *RESULT.  On failure, false is returned.  The caller
+   has to take care of some of the memory management; this function is
+   expected to be called from dynarray-skeleton.c.  */
+bool __libc_dynarray_finalize (struct dynarray_header *list, void *scratch,
+                               size_t element_size,
+                               struct dynarray_finalize_result *result);
+
+
+/* Internal function.  Terminate the process after an index error.
+   SIZE is the number of elements of the dynamic array.  INDEX is the
+   lookup index which triggered the failure.  */
+_Noreturn void __libc_dynarray_at_failure (size_t size, size_t index);
+
+#ifndef _ISOMAC
+libc_hidden_proto (__libc_dynarray_emplace_enlarge)
+libc_hidden_proto (__libc_dynarray_resize)
+libc_hidden_proto (__libc_dynarray_resize_clear)
+libc_hidden_proto (__libc_dynarray_finalize)
+libc_hidden_proto (__libc_dynarray_at_failure)
+#endif
+
+#endif /* _DYNARRAY_H */
diff --git a/lib/malloc/dynarray_at_failure.c b/lib/malloc/dynarray_at_failure.c
new file mode 100644
index 00000000000..a4424593748
--- /dev/null
+++ b/lib/malloc/dynarray_at_failure.c
@@ -0,0 +1,35 @@
+/* Report an dynamic array index out of bounds condition.
+   Copyright (C) 2017-2021 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU General Public
+   License as published by the Free Software Foundation; either
+   version 3 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   General Public License for more details.
+
+   You should have received a copy of the GNU General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#include <dynarray.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+void
+__libc_dynarray_at_failure (size_t size, size_t index)
+{
+#ifdef _LIBC
+  char buf[200];
+  __snprintf (buf, sizeof (buf), "Fatal glibc error: "
+              "array index %zu not less than array length %zu\n",
+              index, size);
+#else
+ abort ();
+#endif
+}
+libc_hidden_def (__libc_dynarray_at_failure)
diff --git a/lib/malloc/dynarray_emplace_enlarge.c b/lib/malloc/dynarray_emplace_enlarge.c
new file mode 100644
index 00000000000..7ac4b6db403
--- /dev/null
+++ b/lib/malloc/dynarray_emplace_enlarge.c
@@ -0,0 +1,73 @@
+/* Increase the size of a dynamic array in preparation of an emplace operation.
+   Copyright (C) 2017-2021 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU General Public
+   License as published by the Free Software Foundation; either
+   version 3 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   General Public License for more details.
+
+   You should have received a copy of the GNU General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#include <dynarray.h>
+#include <errno.h>
+#include <intprops.h>
+#include <stdlib.h>
+#include <string.h>
+
+bool
+__libc_dynarray_emplace_enlarge (struct dynarray_header *list,
+                                 void *scratch, size_t element_size)
+{
+  size_t new_allocated;
+  if (list->allocated == 0)
+    {
+      /* No scratch buffer provided.  Choose a reasonable default
+         size.  */
+      if (element_size < 4)
+        new_allocated = 16;
+      else if (element_size < 8)
+        new_allocated = 8;
+      else
+        new_allocated = 4;
+    }
+  else
+    /* Increase the allocated size, using an exponential growth
+       policy.  */
+    {
+      new_allocated = list->allocated + list->allocated / 2 + 1;
+      if (new_allocated <= list->allocated)
+        {
+          /* Overflow.  */
+          __set_errno (ENOMEM);
+          return false;
+        }
+    }
+
+  size_t new_size;
+  if (INT_MULTIPLY_WRAPV (new_allocated, element_size, &new_size))
+    return false;
+  void *new_array;
+  if (list->array == scratch)
+    {
+      /* The previous array was not heap-allocated.  */
+      new_array = malloc (new_size);
+      if (new_array != NULL && list->array != NULL)
+        memcpy (new_array, list->array, list->used * element_size);
+    }
+  else
+    new_array = realloc (list->array, new_size);
+  if (new_array == NULL)
+    return false;
+  list->array = new_array;
+  list->allocated = new_allocated;
+  return true;
+}
+libc_hidden_def (__libc_dynarray_emplace_enlarge)
diff --git a/lib/malloc/dynarray_finalize.c b/lib/malloc/dynarray_finalize.c
new file mode 100644
index 00000000000..be9441e313d
--- /dev/null
+++ b/lib/malloc/dynarray_finalize.c
@@ -0,0 +1,62 @@
+/* Copy the dynamically-allocated area to an explicitly-sized heap allocation.
+   Copyright (C) 2017-2021 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU General Public
+   License as published by the Free Software Foundation; either
+   version 3 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   General Public License for more details.
+
+   You should have received a copy of the GNU General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#include <dynarray.h>
+#include <stdlib.h>
+#include <string.h>
+
+bool
+__libc_dynarray_finalize (struct dynarray_header *list,
+                          void *scratch, size_t element_size,
+                          struct dynarray_finalize_result *result)
+{
+  if (__dynarray_error (list))
+    /* The caller will reported the deferred error.  */
+    return false;
+
+  size_t used = list->used;
+
+  /* Empty list.  */
+  if (used == 0)
+    {
+      /* An empty list could still be backed by a heap-allocated
+         array.  Free it if necessary.  */
+      if (list->array != scratch)
+        free (list->array);
+      *result = (struct dynarray_finalize_result) { NULL, 0 };
+      return true;
+    }
+
+  size_t allocation_size = used * element_size;
+  void *heap_array = malloc (allocation_size);
+  if (heap_array != NULL)
+    {
+      /* The new array takes ownership of the strings.  */
+      if (list->array != NULL)
+        memcpy (heap_array, list->array, allocation_size);
+      if (list->array != scratch)
+        free (list->array);
+      *result = (struct dynarray_finalize_result)
+        { .array = heap_array, .length = used };
+      return true;
+    }
+  else
+    /* The caller will perform the freeing operation.  */
+    return false;
+}
+libc_hidden_def (__libc_dynarray_finalize)
diff --git a/lib/malloc/dynarray_resize.c b/lib/malloc/dynarray_resize.c
new file mode 100644
index 00000000000..92bbddd4461
--- /dev/null
+++ b/lib/malloc/dynarray_resize.c
@@ -0,0 +1,64 @@
+/* Increase the size of a dynamic array.
+   Copyright (C) 2017-2021 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU General Public
+   License as published by the Free Software Foundation; either
+   version 3 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   General Public License for more details.
+
+   You should have received a copy of the GNU General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#include <dynarray.h>
+#include <errno.h>
+#include <intprops.h>
+#include <stdlib.h>
+#include <string.h>
+
+bool
+__libc_dynarray_resize (struct dynarray_header *list, size_t size,
+                        void *scratch, size_t element_size)
+{
+  /* The existing allocation provides sufficient room.  */
+  if (size <= list->allocated)
+    {
+      list->used = size;
+      return true;
+    }
+
+  /* Otherwise, use size as the new allocation size.  The caller is
+     expected to provide the final size of the array, so there is no
+     over-allocation here.  */
+
+  size_t new_size_bytes;
+  if (INT_MULTIPLY_WRAPV (size, element_size, &new_size_bytes))
+    {
+      /* Overflow.  */
+      __set_errno (ENOMEM);
+      return false;
+    }
+  void *new_array;
+  if (list->array == scratch)
+    {
+      /* The previous array was not heap-allocated.  */
+      new_array = malloc (new_size_bytes);
+      if (new_array != NULL && list->array != NULL)
+        memcpy (new_array, list->array, list->used * element_size);
+    }
+  else
+    new_array = realloc (list->array, new_size_bytes);
+  if (new_array == NULL)
+    return false;
+  list->array = new_array;
+  list->allocated = size;
+  list->used = size;
+  return true;
+}
+libc_hidden_def (__libc_dynarray_resize)
diff --git a/lib/malloc/dynarray_resize_clear.c b/lib/malloc/dynarray_resize_clear.c
new file mode 100644
index 00000000000..99c2cc87c31
--- /dev/null
+++ b/lib/malloc/dynarray_resize_clear.c
@@ -0,0 +1,35 @@
+/* Increase the size of a dynamic array and clear the new part.
+   Copyright (C) 2017-2021 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU General Public
+   License as published by the Free Software Foundation; either
+   version 3 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   General Public License for more details.
+
+   You should have received a copy of the GNU General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#include <dynarray.h>
+#include <string.h>
+
+bool
+__libc_dynarray_resize_clear (struct dynarray_header *list, size_t size,
+                              void *scratch, size_t element_size)
+{
+  size_t old_size = list->used;
+  if (!__libc_dynarray_resize (list, size, scratch, element_size))
+    return false;
+  /* __libc_dynarray_resize already checked for overflow.  */
+  char *array = list->array;
+  memset (array + (old_size * element_size), 0,
+          (size - old_size) * element_size);
+  return true;
+}
+libc_hidden_def (__libc_dynarray_resize_clear)
diff --git a/lib/malloc/scratch_buffer_grow.c b/lib/malloc/scratch_buffer_grow.c
index 41befe3d65f..e7606d81cd7 100644
--- a/lib/malloc/scratch_buffer_grow.c
+++ b/lib/malloc/scratch_buffer_grow.c
@@ -1,5 +1,5 @@
 /* Variable-sized buffer with on-stack default allocation.
-   Copyright (C) 2015-2020 Free Software Foundation, Inc.
+   Copyright (C) 2015-2021 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
 
    The GNU C Library is free software; you can redistribute it and/or
diff --git a/lib/malloc/scratch_buffer_grow_preserve.c b/lib/malloc/scratch_buffer_grow_preserve.c
index aef232938d5..59f8c710001 100644
--- a/lib/malloc/scratch_buffer_grow_preserve.c
+++ b/lib/malloc/scratch_buffer_grow_preserve.c
@@ -1,5 +1,5 @@
 /* Variable-sized buffer with on-stack default allocation.
-   Copyright (C) 2015-2020 Free Software Foundation, Inc.
+   Copyright (C) 2015-2021 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
 
    The GNU C Library is free software; you can redistribute it and/or
diff --git a/lib/malloc/scratch_buffer_set_array_size.c b/lib/malloc/scratch_buffer_set_array_size.c
index 5f5e4c24f5a..e2b9f31211a 100644
--- a/lib/malloc/scratch_buffer_set_array_size.c
+++ b/lib/malloc/scratch_buffer_set_array_size.c
@@ -1,5 +1,5 @@
 /* Variable-sized buffer with on-stack default allocation.
-   Copyright (C) 2015-2020 Free Software Foundation, Inc.
+   Copyright (C) 2015-2021 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
 
    The GNU C Library is free software; you can redistribute it and/or
diff --git a/lib/mini-gmp.c b/lib/mini-gmp.c
index d34fe525e4c..de061e673ac 100644
--- a/lib/mini-gmp.c
+++ b/lib/mini-gmp.c
@@ -4521,7 +4521,7 @@ mpz_export (void *r, size_t *countp, int order, size_t size, int endian,
   mp_size_t un;
 
   if (nails != 0)
-    gmp_die ("mpz_import: Nails not supported.");
+    gmp_die ("mpz_export: Nails not supported.");
 
   assert (order == 1 || order == -1);
   assert (endian >= -1 && endian <= 1);
diff --git a/lib/mktime-internal.h b/lib/mktime-internal.h
index b765a37ee34..9c447bd7b05 100644
--- a/lib/mktime-internal.h
+++ b/lib/mktime-internal.h
@@ -1,5 +1,5 @@
 /* Internals of mktime and related functions
-   Copyright 2016-2020 Free Software Foundation, Inc.
+   Copyright 2016-2021 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
    Contributed by Paul Eggert <eggert@cs.ucla.edu>.
 
diff --git a/lib/nstrftime.c b/lib/nstrftime.c
index 8ba6975552b..2f5e4fbe639 100644
--- a/lib/nstrftime.c
+++ b/lib/nstrftime.c
@@ -19,7 +19,7 @@
 # define USE_IN_EXTENDED_LOCALE_MODEL 1
 # define HAVE_STRUCT_ERA_ENTRY 1
 # define HAVE_TM_GMTOFF 1
-# define HAVE_TM_ZONE 1
+# define HAVE_STRUCT_TM_TM_ZONE 1
 # define HAVE_TZNAME 1
 # include "../locale/localeinfo.h"
 #else
@@ -499,7 +499,7 @@ __strftime_internal (STREAM_OR_CHAR_T *s, STRFTIME_ARG (size_t maxsize)
 #endif
 
   zone = NULL;
-#if HAVE_TM_ZONE
+#if HAVE_STRUCT_TM_TM_ZONE
   /* The POSIX test suite assumes that setting
      the environment variable TZ to a new value before calling strftime()
      will influence the result (the %Z format) even if the information in
@@ -516,7 +516,7 @@ __strftime_internal (STREAM_OR_CHAR_T *s, STRFTIME_ARG (size_t maxsize)
     }
   else
     {
-# if !HAVE_TM_ZONE
+# if !HAVE_STRUCT_TM_TM_ZONE
       /* Infer the zone name from *TZ instead of from TZNAME.  */
       tzname_vec = tz->tzname_copy;
 # endif
diff --git a/lib/regex.c b/lib/regex.c
index 88173bb1052..f76a416b3b5 100644
--- a/lib/regex.c
+++ b/lib/regex.c
@@ -1,5 +1,5 @@
 /* Extended regular expression matching and search library.
-   Copyright (C) 2002-2020 Free Software Foundation, Inc.
+   Copyright (C) 2002-2021 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
    Contributed by Isamu Hasegawa <isamu@yamato.ibm.com>.
 
diff --git a/lib/regex_internal.h b/lib/regex_internal.h
index be2fa4fe78e..4c634edcbfa 100644
--- a/lib/regex_internal.h
+++ b/lib/regex_internal.h
@@ -32,6 +32,7 @@
 #include <stdbool.h>
 #include <stdint.h>
 
+#include <dynarray.h>
 #include <intprops.h>
 #include <verify.h>
 
@@ -444,25 +445,6 @@ typedef struct re_dfa_t re_dfa_t;
 #define re_string_skip_bytes(pstr,idx) ((pstr)->cur_idx += (idx))
 #define re_string_set_index(pstr,idx) ((pstr)->cur_idx = (idx))
 
-#if defined _LIBC || HAVE_ALLOCA
-# include <alloca.h>
-#endif
-
-#ifndef _LIBC
-# if HAVE_ALLOCA
-/* The OS usually guarantees only one guard page at the bottom of the stack,
-   and a page size can be as small as 4096 bytes.  So we cannot safely
-   allocate anything larger than 4096 bytes.  Also care for the possibility
-   of a few compiler-allocated temporary stack slots.  */
-#  define __libc_use_alloca(n) ((n) < 4032)
-# else
-/* alloca is implemented with malloc, so just use malloc.  */
-#  define __libc_use_alloca(n) 0
-#  undef alloca
-#  define alloca(n) malloc (n)
-# endif
-#endif
-
 #ifdef _LIBC
 # define MALLOC_0_IS_NONNULL 1
 #elif !defined MALLOC_0_IS_NONNULL
@@ -848,12 +830,14 @@ re_string_elem_size_at (const re_string_t *pstr, Idx idx)
 }
 #endif /* RE_ENABLE_I18N */
 
-#ifndef FALLTHROUGH
-# if (__GNUC__ >= 7) || (__clang_major__ >= 10)
+#ifdef _LIBC
+# if __GNUC__ >= 7
 #  define FALLTHROUGH __attribute__ ((__fallthrough__))
 # else
 #  define FALLTHROUGH ((void) 0)
 # endif
+#else
+# include "attribute.h"
 #endif
 
 #endif /*  _REGEX_INTERNAL_H */
diff --git a/lib/regexec.c b/lib/regexec.c
index 395e37db591..15dc57bd0e6 100644
--- a/lib/regexec.c
+++ b/lib/regexec.c
@@ -1,5 +1,5 @@
 /* Extended regular expression matching and search library.
-   Copyright (C) 2002-2020 Free Software Foundation, Inc.
+   Copyright (C) 2002-2021 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
    Contributed by Isamu Hasegawa <isamu@yamato.ibm.com>.
 
@@ -1355,6 +1355,12 @@ pop_fail_stack (struct re_fail_stack_t *fs, Idx *pidx, Idx nregs,
   return fs->stack[num].node;
 }
 
+
+#define DYNARRAY_STRUCT  regmatch_list
+#define DYNARRAY_ELEMENT regmatch_t
+#define DYNARRAY_PREFIX  regmatch_list_
+#include <malloc/dynarray-skeleton.c>
+
 /* Set the positions where the subexpressions are starts/ends to registers
    PMATCH.
    Note: We assume that pmatch[0] is already set, and
@@ -1370,8 +1376,8 @@ set_regs (const regex_t *preg, const re_match_context_t *mctx, size_t nmatch,
   re_node_set eps_via_nodes;
   struct re_fail_stack_t *fs;
   struct re_fail_stack_t fs_body = { 0, 2, NULL };
-  regmatch_t *prev_idx_match;
-  bool prev_idx_match_malloced = false;
+  struct regmatch_list prev_match;
+  regmatch_list_init (&prev_match);
 
   DEBUG_ASSERT (nmatch > 1);
   DEBUG_ASSERT (mctx->state_log != NULL);
@@ -1388,18 +1394,13 @@ set_regs (const regex_t *preg, const re_match_context_t *mctx, size_t nmatch,
   cur_node = dfa->init_node;
   re_node_set_init_empty (&eps_via_nodes);
 
-  if (__libc_use_alloca (nmatch * sizeof (regmatch_t)))
-    prev_idx_match = (regmatch_t *) alloca (nmatch * sizeof (regmatch_t));
-  else
+  if (!regmatch_list_resize (&prev_match, nmatch))
     {
-      prev_idx_match = re_malloc (regmatch_t, nmatch);
-      if (prev_idx_match == NULL)
-        {
-          free_fail_stack_return (fs);
-          return REG_ESPACE;
-        }
-      prev_idx_match_malloced = true;
+      regmatch_list_free (&prev_match);
+      free_fail_stack_return (fs);
+      return REG_ESPACE;
     }
+  regmatch_t *prev_idx_match = regmatch_list_begin (&prev_match);
   memcpy (prev_idx_match, pmatch, sizeof (regmatch_t) * nmatch);
 
   for (idx = pmatch[0].rm_so; idx <= pmatch[0].rm_eo ;)
@@ -1417,8 +1418,7 @@ set_regs (const regex_t *preg, const re_match_context_t *mctx, size_t nmatch,
               if (reg_idx == nmatch)
                 {
                   re_node_set_free (&eps_via_nodes);
-                  if (prev_idx_match_malloced)
-                    re_free (prev_idx_match);
+                  regmatch_list_free (&prev_match);
                   return free_fail_stack_return (fs);
                 }
               cur_node = pop_fail_stack (fs, &idx, nmatch, pmatch,
@@ -1427,8 +1427,7 @@ set_regs (const regex_t *preg, const re_match_context_t *mctx, size_t nmatch,
           else
             {
               re_node_set_free (&eps_via_nodes);
-              if (prev_idx_match_malloced)
-                re_free (prev_idx_match);
+              regmatch_list_free (&prev_match);
               return REG_NOERROR;
             }
         }
@@ -1442,8 +1441,7 @@ set_regs (const regex_t *preg, const re_match_context_t *mctx, size_t nmatch,
           if (__glibc_unlikely (cur_node == -2))
             {
               re_node_set_free (&eps_via_nodes);
-              if (prev_idx_match_malloced)
-                re_free (prev_idx_match);
+              regmatch_list_free (&prev_match);
               free_fail_stack_return (fs);
               return REG_ESPACE;
             }
@@ -1453,15 +1451,13 @@ set_regs (const regex_t *preg, const re_match_context_t *mctx, size_t nmatch,
           else
             {
               re_node_set_free (&eps_via_nodes);
-              if (prev_idx_match_malloced)
-                re_free (prev_idx_match);
+              regmatch_list_free (&prev_match);
               return REG_NOMATCH;
             }
         }
     }
   re_node_set_free (&eps_via_nodes);
-  if (prev_idx_match_malloced)
-    re_free (prev_idx_match);
+  regmatch_list_free (&prev_match);
   return free_fail_stack_return (fs);
 }
 
@@ -3251,7 +3247,7 @@ expand_bkref_cache (re_match_context_t *mctx, re_node_set *cur_nodes,
 /* Build transition table for the state.
    Return true if successful.  */
 
-static bool
+static bool __attribute_noinline__
 build_trtable (const re_dfa_t *dfa, re_dfastate_t *state)
 {
   reg_errcode_t err;
@@ -3259,36 +3255,20 @@ build_trtable (const re_dfa_t *dfa, re_dfastate_t *state)
   int ch;
   bool need_word_trtable = false;
   bitset_word_t elem, mask;
-  bool dests_node_malloced = false;
-  bool dest_states_malloced = false;
   Idx ndests; /* Number of the destination states from 'state'.  */
   re_dfastate_t **trtable;
-  re_dfastate_t **dest_states = NULL, **dest_states_word, **dest_states_nl;
-  re_node_set follows, *dests_node;
-  bitset_t *dests_ch;
+  re_dfastate_t *dest_states[SBC_MAX];
+  re_dfastate_t *dest_states_word[SBC_MAX];
+  re_dfastate_t *dest_states_nl[SBC_MAX];
+  re_node_set follows;
   bitset_t acceptable;
 
-  struct dests_alloc
-  {
-    re_node_set dests_node[SBC_MAX];
-    bitset_t dests_ch[SBC_MAX];
-  } *dests_alloc;
-
   /* We build DFA states which corresponds to the destination nodes
      from 'state'.  'dests_node[i]' represents the nodes which i-th
      destination state contains, and 'dests_ch[i]' represents the
      characters which i-th destination state accepts.  */
-  if (__libc_use_alloca (sizeof (struct dests_alloc)))
-    dests_alloc = (struct dests_alloc *) alloca (sizeof (struct dests_alloc));
-  else
-    {
-      dests_alloc = re_malloc (struct dests_alloc, 1);
-      if (__glibc_unlikely (dests_alloc == NULL))
-        return false;
-      dests_node_malloced = true;
-    }
-  dests_node = dests_alloc->dests_node;
-  dests_ch = dests_alloc->dests_ch;
+  re_node_set dests_node[SBC_MAX];
+  bitset_t dests_ch[SBC_MAX];
 
   /* Initialize transition table.  */
   state->word_trtable = state->trtable = NULL;
@@ -3298,8 +3278,6 @@ build_trtable (const re_dfa_t *dfa, re_dfastate_t *state)
   ndests = group_nodes_into_DFAstates (dfa, state, dests_node, dests_ch);
   if (__glibc_unlikely (ndests <= 0))
     {
-      if (dests_node_malloced)
-        re_free (dests_alloc);
       /* Return false in case of an error, true otherwise.  */
       if (ndests == 0)
         {
@@ -3314,38 +3292,14 @@ build_trtable (const re_dfa_t *dfa, re_dfastate_t *state)
 
   err = re_node_set_alloc (&follows, ndests + 1);
   if (__glibc_unlikely (err != REG_NOERROR))
-    goto out_free;
-
-  /* Avoid arithmetic overflow in size calculation.  */
-  size_t ndests_max
-    = ((SIZE_MAX - (sizeof (re_node_set) + sizeof (bitset_t)) * SBC_MAX)
-       / (3 * sizeof (re_dfastate_t *)));
-  if (__glibc_unlikely (ndests_max < ndests))
-    goto out_free;
-
-  if (__libc_use_alloca ((sizeof (re_node_set) + sizeof (bitset_t)) * SBC_MAX
-                         + ndests * 3 * sizeof (re_dfastate_t *)))
-    dest_states = (re_dfastate_t **)
-      alloca (ndests * 3 * sizeof (re_dfastate_t *));
-  else
     {
-      dest_states = re_malloc (re_dfastate_t *, ndests * 3);
-      if (__glibc_unlikely (dest_states == NULL))
-        {
-out_free:
-          if (dest_states_malloced)
-            re_free (dest_states);
-          re_node_set_free (&follows);
-          for (i = 0; i < ndests; ++i)
-            re_node_set_free (dests_node + i);
-          if (dests_node_malloced)
-            re_free (dests_alloc);
-          return false;
-        }
-      dest_states_malloced = true;
+    out_free:
+      re_node_set_free (&follows);
+      for (i = 0; i < ndests; ++i)
+        re_node_set_free (dests_node + i);
+      return false;
     }
-  dest_states_word = dest_states + ndests;
-  dest_states_nl = dest_states_word + ndests;
+
   bitset_empty (acceptable);
 
   /* Then build the states for all destinations.  */
@@ -3470,16 +3424,9 @@ out_free:
           }
     }
 
-  if (dest_states_malloced)
-    re_free (dest_states);
-
   re_node_set_free (&follows);
   for (i = 0; i < ndests; ++i)
     re_node_set_free (dests_node + i);
-
-  if (dests_node_malloced)
-    re_free (dests_alloc);
-
   return true;
 }
 
diff --git a/lib/scratch_buffer.h b/lib/scratch_buffer.h
index 3e2b5ef27db..603b0d65d0a 100644
--- a/lib/scratch_buffer.h
+++ b/lib/scratch_buffer.h
@@ -21,6 +21,7 @@
 
 #include <libc-config.h>
 
+#define __libc_scratch_buffer_dupfree gl_scratch_buffer_dupfree
 #define __libc_scratch_buffer_grow gl_scratch_buffer_grow
 #define __libc_scratch_buffer_grow_preserve gl_scratch_buffer_grow_preserve
 #define __libc_scratch_buffer_set_array_size gl_scratch_buffer_set_array_size
diff --git a/lib/stddef.in.h b/lib/stddef.in.h
index ba7195a9102..0f506a5b18b 100644
--- a/lib/stddef.in.h
+++ b/lib/stddef.in.h
@@ -49,6 +49,23 @@
 
 # ifndef _@GUARD_PREFIX@_STDDEF_H
 
+/* On AIX 7.2, with xlc in 64-bit mode, <stddef.h> defines max_align_t to a
+   type with alignment 4, but 'long' has alignment 8.  */
+#  if defined _AIX && defined _ARCH_PPC64
+#   if !GNULIB_defined_max_align_t
+#    ifdef _MAX_ALIGN_T
+/* /usr/include/stddef.h has already defined max_align_t.  Override it.  */
+typedef long rpl_max_align_t;
+#     define max_align_t rpl_max_align_t
+#    else
+/* Prevent /usr/include/stddef.h from defining max_align_t.  */
+typedef long max_align_t;
+#     define _MAX_ALIGN_T
+#    endif
+#    define GNULIB_defined_max_align_t 1
+#   endif
+#  endif
+
 /* The include_next requires a split double-inclusion guard.  */
 
 #  @INCLUDE_NEXT@ @NEXT_STDDEF_H@
@@ -86,8 +103,10 @@
    we are currently compiling with gcc.
    On MSVC, max_align_t is defined only in C++ mode, after <cstddef> was
    included.  Its definition is good since it has an alignment of 8 (on x86
-   and x86_64).  */
-#if defined _MSC_VER && defined __cplusplus
+   and x86_64).
+   Similarly on OS/2 kLIBC.  */
+#if (defined _MSC_VER || (defined __KLIBC__ && !defined __LIBCN__)) \
+    && defined __cplusplus
 # include <cstddef>
 #else
 # if ! (@HAVE_MAX_ALIGN_T@ || defined _GCC_MAX_ALIGN_T)
diff --git a/lib/string.in.h b/lib/string.in.h
index 9f68e77c767..c76c1820b36 100644
--- a/lib/string.in.h
+++ b/lib/string.in.h
@@ -69,6 +69,14 @@
 # include <unistd.h>
 #endif
 
+/* AIX 7.2 declares ffsl and ffsll in <strings.h>, not in <string.h>.  */
+/* But in any case avoid namespace pollution on glibc systems.  */
+#if ((@GNULIB_FFSL@ || @GNULIB_FFSLL@ || defined GNULIB_POSIXCHECK) \
+     && defined _AIX) \
+    && ! defined __GLIBC__
+# include <strings.h>
+#endif
+
 /* The definitions of _GL_FUNCDECL_RPL etc. are copied here.  */
 
 /* The definition of _GL_ARG_NONNULL is copied here.  */
@@ -110,10 +118,18 @@ _GL_WARN_ON_USE (ffsl, "ffsl is not portable - use the ffsl module");
 
 /* Find the index of the least-significant set bit.  */
 #if @GNULIB_FFSLL@
-# if !@HAVE_FFSLL@
+# if @REPLACE_FFSLL@
+#  if !(defined __cplusplus && defined GNULIB_NAMESPACE)
+#   define ffsll rpl_ffsll
+#  endif
+_GL_FUNCDECL_RPL (ffsll, int, (long long int i));
+_GL_CXXALIAS_RPL (ffsll, int, (long long int i));
+# else
+#  if !@HAVE_FFSLL@
 _GL_FUNCDECL_SYS (ffsll, int, (long long int i));
-# endif
+#  endif
 _GL_CXXALIAS_SYS (ffsll, int, (long long int i));
+# endif
 _GL_CXXALIASWARN (ffsll);
 #elif defined GNULIB_POSIXCHECK
 # undef ffsll
diff --git a/lib/sys_stat.in.h b/lib/sys_stat.in.h
index ccdb5cbd143..13d12943cd0 100644
--- a/lib/sys_stat.in.h
+++ b/lib/sys_stat.in.h
@@ -713,11 +713,21 @@ _GL_WARN_ON_USE (mkfifo, "mkfifo is not portable - "
 
 
 #if @GNULIB_MKFIFOAT@
-# if !@HAVE_MKFIFOAT@
+# if @REPLACE_MKFIFOAT@
+#  if !(defined __cplusplus && defined GNULIB_NAMESPACE)
+#   undef mkfifoat
+#   define mkfifoat rpl_mkfifoat
+#  endif
+_GL_FUNCDECL_RPL (mkfifoat, int, (int fd, char const *file, mode_t mode)
+                                 _GL_ARG_NONNULL ((2)));
+_GL_CXXALIAS_RPL (mkfifoat, int, (int fd, char const *file, mode_t mode));
+# else
+#  if !@HAVE_MKFIFOAT@
 _GL_FUNCDECL_SYS (mkfifoat, int, (int fd, char const *file, mode_t mode)
                                  _GL_ARG_NONNULL ((2)));
-# endif
+#  endif
 _GL_CXXALIAS_SYS (mkfifoat, int, (int fd, char const *file, mode_t mode));
+# endif
 _GL_CXXALIASWARN (mkfifoat);
 #elif defined GNULIB_POSIXCHECK
 # undef mkfifoat
@@ -756,13 +766,25 @@ _GL_WARN_ON_USE (mknod, "mknod is not portable - "
 
 
 #if @GNULIB_MKNODAT@
-# if !@HAVE_MKNODAT@
+# if @REPLACE_MKNODAT@
+#  if !(defined __cplusplus && defined GNULIB_NAMESPACE)
+#   undef mknodat
+#   define mknodat rpl_mknodat
+#  endif
+_GL_FUNCDECL_RPL (mknodat, int,
+                  (int fd, char const *file, mode_t mode, dev_t dev)
+                  _GL_ARG_NONNULL ((2)));
+_GL_CXXALIAS_RPL (mknodat, int,
+                  (int fd, char const *file, mode_t mode, dev_t dev));
+# else
+#  if !@HAVE_MKNODAT@
 _GL_FUNCDECL_SYS (mknodat, int,
                   (int fd, char const *file, mode_t mode, dev_t dev)
                   _GL_ARG_NONNULL ((2)));
-# endif
+#  endif
 _GL_CXXALIAS_SYS (mknodat, int,
                   (int fd, char const *file, mode_t mode, dev_t dev));
+# endif
 _GL_CXXALIASWARN (mknodat);
 #elif defined GNULIB_POSIXCHECK
 # undef mknodat
diff --git a/lib/tempname.c b/lib/tempname.c
index 3d91deef1e1..e243483eaf8 100644
--- a/lib/tempname.c
+++ b/lib/tempname.c
@@ -22,6 +22,7 @@
 
 #include <sys/types.h>
 #include <assert.h>
+#include <stdbool.h>
 
 #include <errno.h>
 
@@ -61,7 +62,8 @@
 # define __gen_tempname gen_tempname
 # define __mkdir mkdir
 # define __open open
-# define __lxstat64(version, file, buf) lstat (file, buf)
+# define __lstat64(file, buf) lstat (file, buf)
+# define __stat64(file, buf) stat (file, buf)
 # define __getrandom getrandom
 # define __clock_gettime64 clock_gettime
 # define __timespec64 timespec
@@ -76,13 +78,14 @@ typedef uint_fast64_t random_value;
 #define BASE_62_POWER (62LL * 62 * 62 * 62 * 62 * 62 * 62 * 62 * 62 * 62)
 
 static random_value
-random_bits (random_value var)
+random_bits (random_value var, bool use_getrandom)
 {
   random_value r;
-  if (__getrandom (&r, sizeof r, 0) == sizeof r)
+  /* Without GRND_NONBLOCK it can be blocked for minutes on some systems.  */
+  if (use_getrandom && __getrandom (&r, sizeof r, GRND_NONBLOCK) == sizeof r)
     return r;
 #if _LIBC || (defined CLOCK_MONOTONIC && HAVE_CLOCK_GETTIME)
-  /* Add entropy if getrandom is not supported.  */
+  /* Add entropy if getrandom did not work.  */
   struct __timespec64 tv;
   __clock_gettime64 (CLOCK_MONOTONIC, &tv);
   var ^= tv.tv_nsec;
@@ -96,7 +99,7 @@ static int
 direxists (const char *dir)
 {
   struct_stat64 buf;
-  return __xstat64 (_STAT_VER, dir, &buf) == 0 && S_ISDIR (buf.st_mode);
+  return __stat64 (dir, &buf) == 0 && S_ISDIR (buf.st_mode);
 }
 
 /* Path search algorithm, for tmpnam, tmpfile, etc.  If DIR is
@@ -188,7 +191,7 @@ try_nocreate (char *tmpl, void *flags _GL_UNUSED)
 {
   struct_stat64 st;
 
-  if (__lxstat64 (_STAT_VER, tmpl, &st) == 0 || errno == EOVERFLOW)
+  if (__lstat64 (tmpl, &st) == 0 || errno == EOVERFLOW)
     __set_errno (EEXIST);
   return errno == ENOENT ? 0 : -1;
 }
@@ -267,6 +270,13 @@ try_tempname_len (char *tmpl, int suffixlen, void *args,
   /* How many random base-62 digits can currently be extracted from V.  */
   int vdigits = 0;
 
+  /* Whether to consume entropy when acquiring random bits.  On the
+     first try it's worth the entropy cost with __GT_NOCREATE, which
+     is inherently insecure and can use the entropy to make it a bit
+     less secure.  On the (rare) second and later attempts it might
+     help against DoS attacks.  */
+  bool use_getrandom = tryfunc == try_nocreate;
+
   /* Least unfair value for V.  If V is less than this, V can generate
      BASE_62_DIGITS digits fairly.  Otherwise it might be biased.  */
   random_value const unfair_min
@@ -290,7 +300,10 @@ try_tempname_len (char *tmpl, int suffixlen, void *args,
           if (vdigits == 0)
             {
               do
-                v = random_bits (v);
+                {
+                  v = random_bits (v, use_getrandom);
+                  use_getrandom = true;
+                }
               while (unfair_min <= v);
 
               vdigits = BASE_62_DIGITS;
diff --git a/lib/time-internal.h b/lib/time-internal.h
index 63a3f9e3db1..067ee729eda 100644
--- a/lib/time-internal.h
+++ b/lib/time-internal.h
@@ -24,7 +24,7 @@ struct tm_zone
      members are zero.  */
   struct tm_zone *next;
 
-#if HAVE_TZNAME && !HAVE_TM_ZONE
+#if HAVE_TZNAME && !HAVE_STRUCT_TM_TM_ZONE
   /* Copies of recent strings taken from tzname[0] and tzname[1].
      The copies are in ABBRS, so that they survive tzset.  Null if unknown.  */
   char *tzname_copy[2];
diff --git a/lib/time.in.h b/lib/time.in.h
index 958dc0bd292..1385980cdf5 100644
--- a/lib/time.in.h
+++ b/lib/time.in.h
@@ -101,6 +101,25 @@ struct __time_t_must_be_integral {
 #  define GNULIB_defined_struct_time_t_must_be_integral 1
 # endif
 
+/* Define TIME_UTC, a positive integer constant used for timespec_get().  */
+# if ! @TIME_H_DEFINES_TIME_UTC@
+#  if !GNULIB_defined_TIME_UTC
+#   define TIME_UTC 1
+#   define GNULIB_defined_TIME_UTC 1
+#  endif
+# endif
+
+/* Set *TS to the current time, and return BASE.
+   Upon failure, return 0.  */
+# if @GNULIB_TIMESPEC_GET@
+#  if ! @HAVE_TIMESPEC_GET@
+_GL_FUNCDECL_SYS (timespec_get, int, (struct timespec *ts, int base)
+                                     _GL_ARG_NONNULL ((1)));
+#  endif
+_GL_CXXALIAS_SYS (timespec_get, int, (struct timespec *ts, int base));
+_GL_CXXALIASWARN (timespec_get);
+# endif
+
 /* Sleep for at least RQTP seconds unless interrupted,  If interrupted,
    return -1 and store the remaining time into RMTP.  See
    <https://pubs.opengroup.org/onlinepubs/9699919799/functions/nanosleep.html>.  */
diff --git a/lib/time_rz.c b/lib/time_rz.c
index 65e20cc5661..3ac053c6219 100644
--- a/lib/time_rz.c
+++ b/lib/time_rz.c
@@ -71,7 +71,7 @@ tzalloc (char const *name)
   if (tz)
     {
       tz->next = NULL;
-#if HAVE_TZNAME && !HAVE_TM_ZONE
+#if HAVE_TZNAME && !HAVE_STRUCT_TM_TM_ZONE
       tz->tzname_copy[0] = tz->tzname_copy[1] = NULL;
 #endif
       tz->tz_is_set = !!name;
@@ -83,13 +83,13 @@ tzalloc (char const *name)
 }
 
 /* Save into TZ any nontrivial time zone abbreviation used by TM, and
-   update *TM (if HAVE_TM_ZONE) or *TZ (if !HAVE_TM_ZONE &&
-   HAVE_TZNAME) if they use the abbreviation.  Return true if
-   successful, false (setting errno) otherwise.  */
+   update *TM (if HAVE_STRUCT_TM_TM_ZONE) or *TZ (if
+   !HAVE_STRUCT_TM_TM_ZONE && HAVE_TZNAME) if they use the abbreviation.
+   Return true if successful, false (setting errno) otherwise.  */
 static bool
 save_abbr (timezone_t tz, struct tm *tm)
 {
-#if HAVE_TM_ZONE || HAVE_TZNAME
+#if HAVE_STRUCT_TM_TM_ZONE || HAVE_TZNAME
   char const *zone = NULL;
   char *zone_copy = (char *) "";
 
@@ -97,7 +97,7 @@ save_abbr (timezone_t tz, struct tm *tm)
   int tzname_index = -1;
 # endif
 
-# if HAVE_TM_ZONE
+# if HAVE_STRUCT_TM_TM_ZONE
   zone = tm->tm_zone;
 # endif
 
@@ -145,7 +145,7 @@ save_abbr (timezone_t tz, struct tm *tm)
     }
 
   /* Replace the zone name so that its lifetime matches that of TZ.  */
-# if HAVE_TM_ZONE
+# if HAVE_STRUCT_TM_TM_ZONE
   tm->tm_zone = zone_copy;
 # else
   if (0 <= tzname_index)
@@ -303,7 +303,7 @@ mktime_z (timezone_t tz, struct tm *tm)
           tm_1.tm_isdst = tm->tm_isdst;
           time_t t = mktime (&tm_1);
           bool ok = 0 <= tm_1.tm_yday;
-#if HAVE_TM_ZONE || HAVE_TZNAME
+#if HAVE_STRUCT_TM_TM_ZONE || HAVE_TZNAME
           ok = ok && save_abbr (tz, &tm_1);
 #endif
           if (revert_tz (old_tz) && ok)
diff --git a/lib/timegm.c b/lib/timegm.c
index fa30943084d..e4127e71c0b 100644
--- a/lib/timegm.c
+++ b/lib/timegm.c
@@ -1,6 +1,6 @@
 /* Convert UTC calendar time to simple time.  Like mktime but assumes UTC.
 
-   Copyright (C) 1994-2020 Free Software Foundation, Inc.
+   Copyright (C) 1994-2021 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
 
    The GNU C Library is free software; you can redistribute it and/or
diff --git a/lib/utimens.c b/lib/utimens.c
index 5bbae058132..44d1ea003e2 100644
--- a/lib/utimens.c
+++ b/lib/utimens.c
@@ -27,6 +27,7 @@
 #include <errno.h>
 #include <fcntl.h>
 #include <stdbool.h>
+#include <string.h>
 #include <sys/stat.h>
 #include <sys/time.h>
 #include <unistd.h>
@@ -52,7 +53,9 @@
 
 /* Avoid recursion with rpl_futimens or rpl_utimensat.  */
 #undef futimens
-#undef utimensat
+#if !HAVE_NEARLY_WORKING_UTIMENSAT
+# undef utimensat
+#endif
 
 /* Solaris 9 mistakenly succeeds when given a non-directory with a
    trailing slash.  Force the use of rpl_stat for a fix.  */
@@ -246,6 +249,20 @@ fdutimens (int fd, char const *file, struct timespec const timespec[2])
 # if HAVE_UTIMENSAT
       if (fd < 0)
         {
+#  if defined __APPLE__ && defined __MACH__
+          size_t len = strlen (file);
+          if (len > 0 && file[len - 1] == '/')
+            {
+              struct stat statbuf;
+              if (stat (file, &statbuf) < 0)
+                return -1;
+              if (!S_ISDIR (statbuf.st_mode))
+                {
+                  errno = ENOTDIR;
+                  return -1;
+                }
+            }
+#  endif
           result = utimensat (AT_FDCWD, file, ts, 0);
 #  ifdef __linux__
           /* Work around a kernel bug:
diff --git a/lib/utimensat.c b/lib/utimensat.c
index 2cea64f6982..9fdecd681f6 100644
--- a/lib/utimensat.c
+++ b/lib/utimensat.c
@@ -24,14 +24,40 @@
 #include <errno.h>
 #include <fcntl.h>
 #include <stdlib.h>
+#include <string.h>
+#include <sys/stat.h>
 
 #include "stat-time.h"
 #include "timespec.h"
 #include "utimens.h"
 
-#if HAVE_UTIMENSAT
+#if HAVE_NEARLY_WORKING_UTIMENSAT
 
+/* Use the original utimensat(), but correct the trailing slash handling.  */
+int
+rpl_utimensat (int fd, char const *file, struct timespec const times[2],
+               int flag)
 # undef utimensat
+{
+  size_t len = strlen (file);
+  if (len && file[len - 1] == '/')
+    {
+      struct stat st;
+      if (fstatat (fd, file, &st, flag & AT_SYMLINK_NOFOLLOW) < 0)
+        return -1;
+      if (!S_ISDIR (st.st_mode))
+        {
+          errno = ENOTDIR;
+          return -1;
+        }
+    }
+
+  return utimensat (fd, file, times, flag);
+}
+
+#else
+
+# if HAVE_UTIMENSAT
 
 /* If we have a native utimensat, but are compiling this file, then
    utimensat was defined to rpl_utimensat by our replacement
@@ -42,24 +68,25 @@
    local_utimensat provides the fallback manipulation.  */
 
 static int local_utimensat (int, char const *, struct timespec const[2], int);
-# define AT_FUNC_NAME local_utimensat
+#  define AT_FUNC_NAME local_utimensat
 
 /* Like utimensat, but work around native bugs.  */
 
 int
 rpl_utimensat (int fd, char const *file, struct timespec const times[2],
                int flag)
+#  undef utimensat
 {
-# if defined __linux__ || defined __sun
+#  if defined __linux__ || defined __sun
   struct timespec ts[2];
-# endif
+#  endif
 
   /* See comments in utimens.c for details.  */
   static int utimensat_works_really; /* 0 = unknown, 1 = yes, -1 = no.  */
   if (0 <= utimensat_works_really)
     {
       int result;
-# if defined __linux__ || defined __sun
+#  if defined __linux__ || defined __sun
       struct stat st;
       /* As recently as Linux kernel 2.6.32 (Dec 2009), several file
          systems (xfs, ntfs-3g) have bugs with a single UTIME_OMIT,
@@ -90,7 +117,7 @@ rpl_utimensat (int fd, char const *file, struct timespec const times[2],
             ts[1] = times[1];
           times = ts;
         }
-#  ifdef __hppa__
+#   ifdef __hppa__
       /* Linux kernel 2.6.22.19 on hppa does not reject invalid tv_nsec
          values.  */
       else if (times
@@ -104,8 +131,36 @@ rpl_utimensat (int fd, char const *file, struct timespec const times[2],
           errno = EINVAL;
           return -1;
         }
+#   endif
+#  endif
+#  if defined __APPLE__ && defined __MACH__
+      /* macOS 10.13 does not reject invalid tv_nsec values either.  */
+      if (times
+          && ((times[0].tv_nsec != UTIME_OMIT
+               && times[0].tv_nsec != UTIME_NOW
+               && ! (0 <= times[0].tv_nsec
+                     && times[0].tv_nsec < TIMESPEC_HZ))
+              || (times[1].tv_nsec != UTIME_OMIT
+                  && times[1].tv_nsec != UTIME_NOW
+                  && ! (0 <= times[1].tv_nsec
+                        && times[1].tv_nsec < TIMESPEC_HZ))))
+        {
+          errno = EINVAL;
+          return -1;
+        }
+      size_t len = strlen (file);
+      if (len > 0 && file[len - 1] == '/')
+        {
+          struct stat statbuf;
+          if (fstatat (fd, file, &statbuf, 0) < 0)
+            return -1;
+          if (!S_ISDIR (statbuf.st_mode))
+            {
+              errno = ENOTDIR;
+              return -1;
+            }
+        }
 #  endif
-# endif
       result = utimensat (fd, file, times, flag);
       /* Linux kernel 2.6.25 has a bug where it returns EINVAL for
          UTIME_NOW or UTIME_OMIT with non-zero tv_sec, which
@@ -129,11 +184,11 @@ rpl_utimensat (int fd, char const *file, struct timespec const times[2],
   return local_utimensat (fd, file, times, flag);
 }
 
-#else /* !HAVE_UTIMENSAT */
+# else /* !HAVE_UTIMENSAT */
 
-# define AT_FUNC_NAME utimensat
+#  define AT_FUNC_NAME utimensat
 
-#endif /* !HAVE_UTIMENSAT */
+# endif /* !HAVE_UTIMENSAT */
 
 /* Set the access and modification timestamps of FILE to be
    TIMESPEC[0] and TIMESPEC[1], respectively; relative to directory
@@ -146,15 +201,17 @@ rpl_utimensat (int fd, char const *file, struct timespec const times[2],
    Return 0 on success, -1 (setting errno) on failure.  */
 
 /* AT_FUNC_NAME is now utimensat or local_utimensat.  */
-#define AT_FUNC_F1 lutimens
-#define AT_FUNC_F2 utimens
-#define AT_FUNC_USE_F1_COND AT_SYMLINK_NOFOLLOW
-#define AT_FUNC_POST_FILE_PARAM_DECLS , struct timespec const ts[2], int flag
-#define AT_FUNC_POST_FILE_ARGS        , ts
-#include "at-func.c"
-#undef AT_FUNC_NAME
-#undef AT_FUNC_F1
-#undef AT_FUNC_F2
-#undef AT_FUNC_USE_F1_COND
-#undef AT_FUNC_POST_FILE_PARAM_DECLS
-#undef AT_FUNC_POST_FILE_ARGS
+# define AT_FUNC_F1 lutimens
+# define AT_FUNC_F2 utimens
+# define AT_FUNC_USE_F1_COND AT_SYMLINK_NOFOLLOW
+# define AT_FUNC_POST_FILE_PARAM_DECLS , struct timespec const ts[2], int flag
+# define AT_FUNC_POST_FILE_ARGS        , ts
+# include "at-func.c"
+# undef AT_FUNC_NAME
+# undef AT_FUNC_F1
+# undef AT_FUNC_F2
+# undef AT_FUNC_USE_F1_COND
+# undef AT_FUNC_POST_FILE_PARAM_DECLS
+# undef AT_FUNC_POST_FILE_ARGS
+
+#endif /* !HAVE_NEARLY_WORKING_UTIMENSAT */
diff --git a/lib/verify.h b/lib/verify.h
index 3cdcdca5671..65514c34b9e 100644
--- a/lib/verify.h
+++ b/lib/verify.h
@@ -22,16 +22,10 @@
 
 
 /* Define _GL_HAVE__STATIC_ASSERT to 1 if _Static_assert (R, DIAGNOSTIC)
-   works as per C11.  This is supported by GCC 4.6.0 and later, in C
-   mode, and by clang (also in C++ mode).
+   works as per C11.  This is supported by GCC 4.6.0+ and by clang 4+.
 
    Define _GL_HAVE__STATIC_ASSERT1 to 1 if _Static_assert (R) works as
-   per C2X.  This is supported by GCC 9.1 and later, and by clang in
-   C++1z mode.
-
-   Define _GL_HAVE_STATIC_ASSERT1 if static_assert (R) works as per
-   C++17.  This is supported by GCC 9.1 and later, and by clang in
-   C++1z mode.
+   per C2X.  This is supported by GCC 9.1+.
 
    Support compilers claiming conformance to the relevant standard,
    and also support GCC when not pedantic.  If we were willing to slow
@@ -47,18 +41,6 @@
       || (!defined __STRICT_ANSI__ && 9 <= __GNUC__))
 #  define _GL_HAVE__STATIC_ASSERT1 1
 # endif
-#else
-# if 4 <= __clang_major__
-#  define _GL_HAVE__STATIC_ASSERT 1
-# endif
-# if 4 <= __clang_major__ && 201411 <= __cpp_static_assert
-#  define _GL_HAVE__STATIC_ASSERT1 1
-# endif
-# if 201703L <= __cplusplus \
-     || 9 <= __GNUC__ \
-     || (4 <= __clang_major__ && 201411 <= __cpp_static_assert)
-#  define _GL_HAVE_STATIC_ASSERT1 1
-# endif
 #endif
 
 /* FreeBSD 9.1 <sys/cdefs.h>, included by <stddef.h> and lots of other
@@ -225,7 +207,9 @@ template <int w>
    Unfortunately, unlike C11, this implementation must appear as an
    ordinary declaration, and cannot appear inside struct { ... }.  */
 
-#if defined _GL_HAVE__STATIC_ASSERT
+#if 200410 <= __cpp_static_assert
+# define _GL_VERIFY(R, DIAGNOSTIC, ...) static_assert (R, DIAGNOSTIC)
+#elif defined _GL_HAVE__STATIC_ASSERT
 # define _GL_VERIFY(R, DIAGNOSTIC, ...) _Static_assert (R, DIAGNOSTIC)
 #else
 # define _GL_VERIFY(R, DIAGNOSTIC, ...)                                \
@@ -239,7 +223,7 @@ template <int w>
 #  define _Static_assert(...) \
      _GL_VERIFY (__VA_ARGS__, "static assertion failed", -)
 # endif
-# if !defined _GL_HAVE_STATIC_ASSERT1 && !defined static_assert
+# if __cpp_static_assert < 201411 && !defined static_assert
 #  define static_assert _Static_assert /* C11 requires this #define.  */
 # endif
 #endif
diff --git a/lisp/calc/calc-embed.el b/lisp/calc/calc-embed.el
index ea79bfa69a0..fda0b4bbedb 100644
--- a/lisp/calc/calc-embed.el
+++ b/lisp/calc/calc-embed.el
@@ -651,6 +651,8 @@ The command \\[yank] can retrieve it from there."
 (defvar calc-embed-prev-modes)
 
 (defun calc-embedded-set-modes (gmodes modes local-modes &optional temp)
+  (defvar the-language)
+  (defvar the-display-just)
   (let ((the-language (calc-embedded-language))
         (the-display-just (calc-embedded-justify))
         (v gmodes)
diff --git a/lisp/calc/calc-lang.el b/lisp/calc/calc-lang.el
index b4b2d4cc4f4..0117f449dd5 100644
--- a/lisp/calc/calc-lang.el
+++ b/lisp/calc/calc-lang.el
@@ -2181,7 +2181,7 @@ order to Calc's."
                    v math-read-big-baseline))
 
             ;; Small radical sign.
-            ((and (= other-char ?V)
+            ((and (memq other-char '(?V ?√))
                   (= (math-read-big-char (1+ math-rb-h1) (1- v)) ?\_))
              (setq h (1+ math-rb-h1))
              (math-read-big-emptyp math-rb-h1 math-rb-v1 h (1- v) nil t)
diff --git a/lisp/calc/calc.el b/lisp/calc/calc.el
index d684c7ba97f..ec09abb34c4 100644
--- a/lisp/calc/calc.el
+++ b/lisp/calc/calc.el
@@ -2144,7 +2144,7 @@ the United States."
                 (let ((w (split-window nil (/ (* (window-width) 2) 3) t)))
                   (set-window-buffer w calc-trail-buffer)
                   (and calc-make-windows-dedicated
-                       (set-window-dedicated-p nil t))))
+                       (set-window-dedicated-p w t))))
               (calc-wrapper
                (setq overlay-arrow-string calc-trail-overlay
                      overlay-arrow-position calc-trail-pointer)
diff --git a/lisp/calc/calccomp.el b/lisp/calc/calccomp.el
index 07e70cad0a8..bd81d7fe406 100644
--- a/lisp/calc/calccomp.el
+++ b/lisp/calc/calccomp.el
@@ -138,19 +138,19 @@
                                       (math-format-number (nth 2 aa))))))
                   (if (= calc-number-radix 10)
                       c
-                    (list 'horiz "(" c
-                          (list 'subscr ")"
-                                (int-to-string calc-number-radix)))))
+                    (list 'subscr (math--comp-round-bracket c)
+                          (int-to-string calc-number-radix))))
               (math-format-number a)))
         (if (not (eq calc-language 'big))
             (math-format-number a prec)
           (if (memq (car-safe a) '(cplx polar))
               (if (math-zerop (nth 2 a))
                   (math-compose-expr (nth 1 a) prec)
-                (list 'horiz "("
-                      (math-compose-expr (nth 1 a) 0)
-                      (if (eq (car a) 'cplx) ", " "; ")
-                      (math-compose-expr (nth 2 a) 0) ")"))
+                (math--comp-round-bracket
+                 (list 'horiz
+                       (math-compose-expr (nth 1 a) 0)
+                       (if (eq (car a) 'cplx) ", " "; ")
+                       (math-compose-expr (nth 2 a) 0))))
             (if (or (= calc-number-radix 10)
                     (not (Math-realp a))
                     (and calc-group-digits
@@ -340,12 +340,13 @@
               (funcall spfn a prec)
             (math-compose-var a)))))
      ((eq (car a) 'intv)
-      (list 'horiz
-            (if (memq (nth 1 a) '(0 1)) "(" "[")
-            (math-compose-expr (nth 2 a) 0)
-            " .. "
-            (math-compose-expr (nth 3 a) 0)
-            (if (memq (nth 1 a) '(0 2)) ")" "]")))
+      (math--comp-bracket
+       (if (memq (nth 1 a) '(0 1)) ?\( ?\[)
+       (if (memq (nth 1 a) '(0 2)) ?\) ?\])
+       (list 'horiz
+             (math-compose-expr (nth 2 a) 0)
+             " .. "
+             (math-compose-expr (nth 3 a) 0))))
      ((eq (car a) 'date)
       (if (eq (car calc-date-format) 'X)
           (math-format-date a)
@@ -377,7 +378,7 @@
                     (and (eq (car-safe (nth 1 a)) 'cplx)
                          (math-negp (nth 1 (nth 1 a)))
                          (eq (nth 2 (nth 1 a)) 0)))
-                (list 'horiz "(" (math-compose-expr (nth 1 a) 0) ")")
+                (math--comp-round-bracket (math-compose-expr (nth 1 a) 0))
               (math-compose-expr (nth 1 a) 201))
             (let ((calc-language 'flat)
                   (calc-number-radix 10)
@@ -444,7 +445,7 @@
         (if (> prec (nth 2 a))
             (if (setq spfn (get calc-language 'math-big-parens))
                 (list 'horiz (car spfn) c (cdr spfn))
-              (list 'horiz "(" c ")"))
+              (math--comp-round-bracket c))
           c)))
      ((and (eq (car a) 'calcFunc-choriz)
            (not (eq calc-language 'unform))
@@ -612,7 +613,7 @@
                            (list 'horiz "{left ( "
                                  (math-compose-expr a -1)
                                  " right )}")))
-                     (list 'horiz "(" (math-compose-expr a 0) ")"))))
+                     (math--comp-round-bracket (math-compose-expr a 0)))))
                 ((and (memq calc-language '(tex latex))
                       (memq (car a) '(/ calcFunc-choose calcFunc-evalto))
                       (>= prec 0))
@@ -638,7 +639,7 @@
                         (rhs (math-compose-expr (nth 2 a) (nth 3 op) (eq (nth 1 op) '/))))
                    (and (equal (car op) "^")
                         (eq (math-comp-first-char lhs) ?-)
-                        (setq lhs (list 'horiz "(" lhs ")")))
+                        (setq lhs (math--comp-round-bracket lhs)))
                    (and (memq calc-language '(tex latex))
                         (or (equal (car op) "^") (equal (car op) "_"))
                         (not (and (stringp rhs) (= (length rhs) 1)))
@@ -721,7 +722,7 @@
                            (list 'horiz "{left ( "
                                  (math-compose-expr a -1)
                                  " right )}")))
-                     (list 'horiz "(" (math-compose-expr a 0) ")"))))
+                     (math--comp-round-bracket (math-compose-expr a 0)))))
                 (t
                  (let ((lhs (math-compose-expr (nth 1 a) (nth 2 op))))
                  (list 'horiz
@@ -759,7 +760,7 @@
                            (list 'horiz "{left ( "
                                  (math-compose-expr a -1)
                                  " right )}")))
-                     (list 'horiz "(" (math-compose-expr a 0) ")"))))
+                     (math--comp-round-bracket (math-compose-expr a 0)))))
                 (t
                  (let ((rhs (math-compose-expr (nth 1 a) (nth 3 op))))
                    (list 'horiz
@@ -821,9 +822,16 @@
                  (if (setq spfn (get calc-language 'math-func-formatter))
                      (funcall spfn func a)
 
-                   (list 'horiz func calc-function-open
-                       (math-compose-vector (cdr a) ", " 0)
-                       calc-function-close))))))))))
+                   (let ((args (math-compose-vector (cdr a) ", " 0)))
+                     (if (and (member calc-function-open '("(" "[" "{"))
+                              (member calc-function-close '(")" "]" "}")))
+                         (list 'horiz func
+                               (math--comp-bracket
+                                (string-to-char calc-function-open)
+                                (string-to-char calc-function-close)
+                                args))
+                       (list 'horiz func calc-function-open
+                             args calc-function-close))))))))))))
 
 
 (defun math-prod-first-term (x)
@@ -966,6 +974,69 @@
       (and (memq (car a) '(^ calcFunc-subscr))
            (math-tex-expr-is-flat (nth 1 a)))))
 
+;; FIXME: maybe try box drawing chars if big bracket chars are unavailable,
+;; like  ┌     ┐n
+;;       │a + b│     ┌ a + b ┐n
+;;       │-----│  or │ ----- │    ?
+;;       │  c  │     └   c   ┘
+;;       └     ┘
+;; They are more common than the chars below, but look a bit square.
+;; Rounded corners exist but are less commonly available.
+
+(defconst math--big-bracket-alist
+  '((?\( . (?⎛ ?⎝ ?⎜))
+    (?\) . (?⎞ ?⎠ ?⎟))
+    (?\[ . (?⎡ ?⎣ ?⎢))
+    (?\] . (?⎤ ?⎦ ?⎥))
+    (?\{ . (?⎧ ?⎩ ?⎪ ?⎨))
+    (?\} . (?⎫ ?⎭ ?⎪ ?⎬)))
+  "Alist mapping bracket chars to (UPPER LOWER EXTENSION MIDPIECE).
+Not all brackets have midpieces.")
+
+(defun math--big-bracket (bracket-char height baseline)
+  "Composition for BRACKET-CHAR of HEIGHT with BASELINE."
+  (if (<= height 1)
+      (char-to-string bracket-char)
+    (let ((pieces (cdr (assq bracket-char math--big-bracket-alist))))
+      (if (memq nil (mapcar #'char-displayable-p pieces))
+          (char-to-string bracket-char)
+        (let* ((upper (nth 0 pieces))
+               (lower (nth 1 pieces))
+               (extension (nth 2 pieces))
+               (midpiece (nth 3 pieces)))
+          (cons 'vleft        ; alignment doesn't matter; width is 1 char
+                (cons baseline
+                      (mapcar
+                       #'char-to-string
+                       (append
+                        (list upper)
+                        (if midpiece
+                            (let ((lower-ext (/ (- height 3) 2)))
+                              (append
+                               (make-list (- height 3 lower-ext) extension)
+                               (list midpiece)
+                               (make-list lower-ext extension)))
+                          (make-list (- height 2) extension))
+                        (list lower))))))))))
+
+(defun math--comp-bracket (left-bracket right-bracket comp)
+  "Put the composition COMP inside LEFT-BRACKET and RIGHT-BRACKET."
+  (if (eq calc-language 'big)
+      (let ((height (math-comp-height comp))
+            (baseline (1- (math-comp-ascent comp))))
+        (list 'horiz
+              (math--big-bracket left-bracket height baseline)
+              comp
+              (math--big-bracket right-bracket height baseline)))
+    (list 'horiz
+          (char-to-string left-bracket)
+          comp
+          (char-to-string right-bracket))))
+
+(defun math--comp-round-bracket (comp)
+  "Put the composition COMP inside plain brackets."
+  (math--comp-bracket ?\( ?\) comp))
+
 (put 'calcFunc-log 'math-compose-big #'math-compose-log)
 (defun math-compose-log (a _prec)
   (and (= (length a) 3)
@@ -973,18 +1044,14 @@
              (list 'subscr "log"
                    (let ((calc-language 'flat))
                      (math-compose-expr (nth 2 a) 1000)))
-             "("
-             (math-compose-expr (nth 1 a) 1000)
-             ")")))
+             (math--comp-round-bracket (math-compose-expr (nth 1 a) 1000)))))
 
 (put 'calcFunc-log10 'math-compose-big #'math-compose-log10)
 (defun math-compose-log10 (a _prec)
   (and (= (length a) 2)
        (list 'horiz
-             (list 'subscr "log" "10")
-             "("
-             (math-compose-expr (nth 1 a) 1000)
-             ")")))
+             (list 'subscr "log" "10")
+             (math--comp-round-bracket (math-compose-expr (nth 1 a) 1000)))))
 
 (put 'calcFunc-deriv 'math-compose-big #'math-compose-deriv)
 (put 'calcFunc-tderiv 'math-compose-big #'math-compose-deriv)
@@ -1027,12 +1094,9 @@
 (defun math-compose-choose (a _prec)
   (let ((a1 (math-compose-expr (nth 1 a) 0))
         (a2 (math-compose-expr (nth 2 a) 0)))
-    (list 'horiz
-          "("
-          (list 'vcent
-                (math-comp-height a1)
-                a1 " " a2)
-          ")")))
+    (math--comp-round-bracket (list 'vcent
+                                    (+ (math-comp-height a1))
+                                    a1 " " a2))))
 
 (put 'calcFunc-integ 'math-compose-big #'math-compose-integ)
 (defun math-compose-integ (a prec)
@@ -1052,9 +1116,12 @@
                                                        "d%s"
                                                        (nth 1 (nth 2 a)))))
                                          (nth 1 a)) 185))
-              (calc-language 'flat)
-              (low (and (nth 3 a) (math-compose-expr (nth 3 a) 0)))
-              (high (and (nth 4 a) (math-compose-expr (nth 4 a) 0)))
+              (low (and (nth 3 a)
+                        (let ((calc-language 'flat))
+                          (math-compose-expr (nth 3 a) 0))))
+              (high (and (nth 4 a)
+                         (let ((calc-language 'flat))
+                           (math-compose-expr (nth 4 a) 0))))
               ;; Check if we have Unicode integral top/bottom parts.
               (fancy (and (char-displayable-p ?⌠)
                           (char-displayable-p ?⌡)))
@@ -1066,40 +1133,47 @@
                                 ((char-displayable-p ?│) "│ ")
                                 ;; U+007C VERTICAL LINE
                                 (t "| "))))
-         (list 'horiz
-               (if parens "(" "")
-               (append (list 'vcent (if fancy
-                                        (if high 2 1)
-                                      (if high 3 2)))
-                       (and high (list (if fancy
-                                           (list 'horiz high " ")
-                                         (list 'horiz "  " high))))
-                       (if fancy
-                           (list "⌠ " fancy-stem "⌡ ")
-                         '("  /"
-                           " | "
-                           " | "
-                           " | "
-                           "/  "))
-                       (and low (list (if fancy
-                                          (list 'horiz low " ")
-                                        (list 'horiz low "  ")))))
-               expr
-               (if over
-                   ""
-                 (list 'horiz " d" var))
-               (if parens ")" "")))))
+         (let ((comp
+                (list 'horiz
+                      (append (list 'vcent (if fancy
+                                               (if high 2 1)
+                                             (if high 3 2)))
+                              (and high (list (if fancy
+                                                  (list 'horiz high " ")
+                                                (list 'horiz "  " high))))
+                              (if fancy
+                                  (list "⌠ " fancy-stem "⌡ ")
+                                '("  /"
+                                  " | "
+                                  " | "
+                                  " | "
+                                  "/  "))
+                              (and low (list (if fancy
+                                                 (list 'horiz low " ")
+                                               (list 'horiz low "  ")))))
+                      expr
+                      (if over
+                          ""
+                        (list 'horiz " d" var)))))
+           (if parens
+               (math--comp-round-bracket comp)
+             comp)))))
 
 (put 'calcFunc-sum 'math-compose-big #'math-compose-sum)
 (defun math-compose-sum (a prec)
   (and (memq (length a) '(3 5 6))
        (let* ((expr (math-compose-expr (nth 1 a) 185))
-              (calc-language 'flat)
-              (var (math-compose-expr (nth 2 a) 0))
-              (low (and (nth 3 a) (math-compose-expr (nth 3 a) 0)))
-              (high (and (nth 4 a) (math-compose-vector (nthcdr 4 a) ", " 0))))
-         (list 'horiz
-               (if (memq prec '(180 201)) "(" "")
+              (var
+               (let ((calc-language 'flat))
+                 (math-compose-expr (nth 2 a) 0)))
+              (low (and (nth 3 a)
+                        (let ((calc-language 'flat))
+                          (math-compose-expr (nth 3 a) 0))))
+              (high (and (nth 4 a)
+                         (let ((calc-language 'flat))
+                           (math-compose-vector (nthcdr 4 a) ", " 0))))
+              (comp
+               (list 'horiz
                (append (list 'vcent (if high 3 2))
                        (and high (list high))
                        '("---- "
@@ -1112,32 +1186,42 @@
                          (list var)))
                (if (memq (car-safe (nth 1 a)) '(calcFunc-sum calcFunc-prod))
                    " " "")
-               expr
-               (if (memq prec '(180 201)) ")" "")))))
+               expr)))
+         (if (memq prec '(180 201))
+             (math--comp-round-bracket comp)
+           comp))))
 
 (put 'calcFunc-prod 'math-compose-big #'math-compose-prod)
 (defun math-compose-prod (a prec)
   (and (memq (length a) '(3 5 6))
        (let* ((expr (math-compose-expr (nth 1 a) 198))
-              (calc-language 'flat)
-              (var (math-compose-expr (nth 2 a) 0))
-              (low (and (nth 3 a) (math-compose-expr (nth 3 a) 0)))
-              (high (and (nth 4 a) (math-compose-vector (nthcdr 4 a) ", " 0))))
-         (list 'horiz
-               (if (memq prec '(196 201)) "(" "")
-               (append (list 'vcent (if high 3 2))
-                       (and high (list high))
-                       '("----- "
-                         " | |  "
-                         " | |  "
-                         " | |  ")
-                       (if low
-                           (list (list 'horiz var " = " low))
-                         (list var)))
-               (if (memq (car-safe (nth 1 a)) '(calcFunc-sum calcFunc-prod))
-                   " " "")
-               expr
-               (if (memq prec '(196 201)) ")" "")))))
+              (var
+               (let ((calc-language 'flat))
+                 (math-compose-expr (nth 2 a) 0)))
+              (low (and (nth 3 a)
+                        (let ((calc-language 'flat))
+                          (math-compose-expr (nth 3 a) 0))))
+              (high (and (nth 4 a)
+                         (let ((calc-language 'flat))
+                           (math-compose-vector (nthcdr 4 a) ", " 0))))
+              (comp
+               (list 'horiz
+                     (append (list 'vcent (if high 3 2))
+                             (and high (list high))
+                             '("----- "
+                               " | |  "
+                               " | |  "
+                               " | |  ")
+                             (if low
+                                 (list (list 'horiz var " = " low))
+                               (list var)))
+                     (if (memq (car-safe (nth 1 a))
+                               '(calcFunc-sum calcFunc-prod))
+                         " " "")
+                     expr)))
+         (if (memq prec '(196 201))
+             (math--comp-round-bracket comp)
+           comp))))
 
 ;; The variables math-svo-c, math-svo-wid and math-svo-off are local
 ;; to math-stack-value-offset in calc.el, but are used by
diff --git a/lisp/calendar/cal-bahai.el b/lisp/calendar/cal-bahai.el
index 22e4cdbcd52..c2e4205c0bc 100644
--- a/lisp/calendar/cal-bahai.el
+++ b/lisp/calendar/cal-bahai.el
@@ -1,4 +1,4 @@
-;;; cal-bahai.el --- calendar functions for the Bahá’í calendar.
+;;; cal-bahai.el --- calendar functions for the Bahá’í calendar.  -*- lexical-binding: t; -*-
 
 ;; Copyright (C) 2001-2021 Free Software Foundation, Inc.
 
@@ -124,9 +124,10 @@ Defaults to today's date if DATE is not given."
          (y (calendar-extract-year bahai-date)))
     (if (< y 1)
         ""                              ; pre-Bahai
-      (let* ((m (calendar-extract-month bahai-date))
-             (d (calendar-extract-day bahai-date))
-             (monthname (if (and (= m 19)
+      (let ((m (calendar-extract-month bahai-date))
+            (d (calendar-extract-day bahai-date)))
+        (calendar-dlet*
+            ((monthname (if (and (= m 19)
                                  (<= d 0))
                             "Ayyám-i-Há"
                           (aref calendar-bahai-month-name-array (1- m))))
@@ -137,8 +138,8 @@ Defaults to today's date if DATE is not given."
              (year (number-to-string y))
              (month (number-to-string m))
              dayname)
-        ;; Can't call calendar-date-string because of monthname oddity.
-        (mapconcat 'eval calendar-date-display-form "")))))
+          ;; Can't call calendar-date-string because of monthname oddity.
+          (mapconcat #'eval calendar-date-display-form ""))))))
 
 ;;;###cal-autoload
 (defun calendar-bahai-print-date ()
@@ -153,13 +154,12 @@ Defaults to today's date if DATE is not given."
  "Interactively read the arguments for a Bahá’í date command.
 Reads a year, month and day."
   (let* ((today (calendar-current-date))
-         (year (calendar-read
-                "Bahá’í calendar year (not 0): "
+         (year (calendar-read-sexp
+                "Bahá’í calendar year (not 0)"
                 (lambda (x) (not (zerop x)))
-                (number-to-string
-                 (calendar-extract-year
-                  (calendar-bahai-from-absolute
-                   (calendar-absolute-from-gregorian today))))))
+                (calendar-extract-year
+                 (calendar-bahai-from-absolute
+                  (calendar-absolute-from-gregorian today)))))
          (completion-ignore-case t)
          (month (cdr (assoc
                       (completing-read
@@ -169,8 +169,8 @@ Reads a year, month and day."
                        nil t)
                       (calendar-make-alist calendar-bahai-month-name-array
                                            1))))
-         (day (calendar-read "Bahá’í calendar day (1-19): "
-                             (lambda (x) (and (< 0 x) (<= x 19))))))
+         (day (calendar-read-sexp "Bahá’í calendar day (1-19)"
+                                  (lambda (x) (and (< 0 x) (<= x 19))))))
     (list (list month day year))))
 
 ;;;###cal-autoload
diff --git a/lisp/calendar/cal-china.el b/lisp/calendar/cal-china.el
index 7e5d0c46e11..9a28984a7ab 100644
--- a/lisp/calendar/cal-china.el
+++ b/lisp/calendar/cal-china.el
@@ -1,4 +1,4 @@
-;;; cal-china.el --- calendar functions for the Chinese calendar
+;;; cal-china.el --- calendar functions for the Chinese calendar  -*- lexical-binding: t; -*-
 
 ;; Copyright (C) 1995, 1997, 2001-2021 Free Software Foundation, Inc.
 
@@ -185,7 +185,9 @@ N congruent to 1 gives the first name, N congruent to 2 gives the second name,
 (defun calendar-chinese-zodiac-sign-on-or-after (d)
   "Absolute date of first new Zodiac sign on or after absolute date D.
 The Zodiac signs begin when the sun's longitude is a multiple of 30 degrees."
- (let* ((year (calendar-extract-year (calendar-gregorian-from-absolute d)))
+  (with-suppressed-warnings ((lexical year))
+    (defvar year))
+  (let* ((year (calendar-extract-year (calendar-gregorian-from-absolute d)))
          (calendar-time-zone (eval calendar-chinese-time-zone)) ; uses year
          (calendar-daylight-time-offset
           calendar-chinese-daylight-time-offset)
@@ -207,6 +209,8 @@ The Zodiac signs begin when the sun's longitude is a multiple of 30 degrees."
 
 (defun calendar-chinese-new-moon-on-or-after (d)
   "Absolute date of first new moon on or after absolute date D."
+  (with-suppressed-warnings ((lexical year))
+    (defvar year))
   (let* ((year (calendar-extract-year (calendar-gregorian-from-absolute d)))
          (calendar-time-zone (eval calendar-chinese-time-zone))
          (calendar-daylight-time-offset
@@ -602,14 +606,14 @@ Echo Chinese date unless NOECHO is non-nil."
   (interactive
    (let* ((c (calendar-chinese-from-absolute
               (calendar-absolute-from-gregorian (calendar-current-date))))
-          (cycle (calendar-read
-                  "Chinese calendar cycle number (>44): "
+          (cycle (calendar-read-sexp
+                  "Chinese calendar cycle number (>44)"
                   (lambda (x) (> x 44))
-                  (number-to-string (car c))))
-          (year (calendar-read
-                 "Year in Chinese cycle (1..60): "
+                  (car c)))
+          (year (calendar-read-sexp
+                 "Year in Chinese cycle (1..60)"
                  (lambda (x) (and (<= 1 x) (<= x 60)))
-                 (number-to-string (cadr c))))
+                 (cadr c)))
           (month-list (calendar-chinese-months-to-alist
                        (calendar-chinese-months cycle year)))
           (month (cdr (assoc
@@ -624,9 +628,11 @@ Echo Chinese date unless NOECHO is non-nil."
                                  (list cycle year month 1))))))
                     30
                   29))
-          (day (calendar-read
-                (format "Chinese calendar day (1-%d): " last)
-                (lambda (x) (and (<= 1 x) (<= x last))))))
+          (day (calendar-read-sexp
+                "Chinese calendar day (1-%d)"
+                (lambda (x) (and (<= 1 x) (<= x last)))
+                nil
+                last)))
      (list (list cycle year month day))))
   (calendar-goto-date (calendar-gregorian-from-absolute
                        (calendar-chinese-to-absolute date)))
@@ -663,17 +669,17 @@ Echo Chinese date unless NOECHO is non-nil."
   ["正月" "二月" "三月" "四月" "五月" "六月"
    "七月" "八月" "九月" "十月" "冬月" "臘月"])
 
-;;; NOTE: In the diary the cycle and year of a Chinese date is
-;;; combined using this formula: (+ (* cycle 100) year).
+;; NOTE: In the diary the cycle and year of a Chinese date is
+;; combined using this formula: (+ (* cycle 100) year).
 ;;;
-;;; These two functions convert to and back from this representation.
-(defun calendar-chinese-from-absolute-for-diary (date)
-  (pcase-let ((`(,c ,y ,m ,d) (calendar-chinese-from-absolute date)))
+;; These two functions convert to and back from this representation.
+(defun calendar-chinese-from-absolute-for-diary (thedate)
+  (pcase-let ((`(,c ,y ,m ,d) (calendar-chinese-from-absolute thedate)))
     ;; Note: For leap months M is a float.
     (list (floor m) d (+ (* c 100) y))))
 
-(defun calendar-chinese-to-absolute-for-diary (date &optional prefer-leap)
-  (pcase-let* ((`(,m ,d ,y) date)
+(defun calendar-chinese-to-absolute-for-diary (thedate &optional prefer-leap)
+  (pcase-let* ((`(,m ,d ,y) thedate)
                (cycle (floor y 100))
                (year (mod y 100))
                (months (calendar-chinese-months cycle year))
@@ -691,7 +697,8 @@ Echo Chinese date unless NOECHO is non-nil."
   (unless (zerop month)
     (calendar-mark-1 month day year
                      #'calendar-chinese-from-absolute-for-diary
-                     (lambda (date) (calendar-chinese-to-absolute-for-diary date t))
+                     (lambda (thedate)
+                       (calendar-chinese-to-absolute-for-diary thedate t))
                      color)))
 
 ;;;###cal-autoload
diff --git a/lisp/calendar/cal-coptic.el b/lisp/calendar/cal-coptic.el
index 3461f3259b9..346585e1817 100644
--- a/lisp/calendar/cal-coptic.el
+++ b/lisp/calendar/cal-coptic.el
@@ -1,4 +1,4 @@
-;;; cal-coptic.el --- calendar functions for the Coptic/Ethiopic calendars
+;;; cal-coptic.el --- calendar functions for the Coptic/Ethiopic calendars  -*- lexical-binding: t; -*-
 
 ;; Copyright (C) 1995, 1997, 2001-2021 Free Software Foundation, Inc.
 
@@ -116,12 +116,13 @@ Defaults to today's date if DATE is not given."
          (m (calendar-extract-month coptic-date)))
     (if (< y 1)
         ""
-      (let ((monthname (aref calendar-coptic-month-name-array (1- m)))
-            (day (number-to-string (calendar-extract-day coptic-date)))
-            (dayname nil)
-            (month (number-to-string m))
-            (year (number-to-string y)))
-        (mapconcat 'eval calendar-date-display-form "")))))
+      (calendar-dlet*
+          ((monthname (aref calendar-coptic-month-name-array (1- m)))
+           (day (number-to-string (calendar-extract-day coptic-date)))
+           (dayname nil)
+           (month (number-to-string m))
+           (year (number-to-string y)))
+        (mapconcat #'eval calendar-date-display-form "")))))
 
 ;;;###cal-autoload
 (defun calendar-coptic-print-date ()
@@ -136,13 +137,13 @@ Defaults to today's date if DATE is not given."
   "Interactively read the arguments for a Coptic date command.
 Reads a year, month, and day."
   (let* ((today (calendar-current-date))
-         (year (calendar-read
-                (format "%s calendar year (>0): " calendar-coptic-name)
+         (year (calendar-read-sexp
+                "%s calendar year (>0)"
                 (lambda (x) (> x 0))
-                (number-to-string
-                 (calendar-extract-year
-                  (calendar-coptic-from-absolute
-                   (calendar-absolute-from-gregorian today))))))
+                (calendar-extract-year
+                 (calendar-coptic-from-absolute
+                  (calendar-absolute-from-gregorian today)))
+                calendar-coptic-name))
          (completion-ignore-case t)
          (month (cdr (assoc-string
                       (completing-read
@@ -151,11 +152,14 @@ Reads a year, month, and day."
                                (append calendar-coptic-month-name-array nil))
                        nil t)
                       (calendar-make-alist calendar-coptic-month-name-array
-                                           1) t)))
+                                           1)
+                      t)))
          (last (calendar-coptic-last-day-of-month month year))
-         (day (calendar-read
-               (format "%s calendar day (1-%d): " calendar-coptic-name last)
-               (lambda (x) (and (< 0 x) (<= x last))))))
+         (day (calendar-read-sexp
+               "%s calendar day (1-%d)"
+               (lambda (x) (and (< 0 x) (<= x last)))
+               nil
+               calendar-coptic-name last)))
     (list (list month day year))))
 
 ;;;###cal-autoload
@@ -194,30 +198,30 @@ Echo Coptic date unless NOECHO is t."
 (defconst calendar-ethiopic-name "Ethiopic"
   "Used in some message strings.")
 
-(defun calendar-ethiopic-to-absolute (date)
+(defun calendar-ethiopic-to-absolute (thedate)
   "Compute absolute date from Ethiopic date DATE.
 The absolute date is the number of days elapsed since the (imaginary)
 Gregorian date Sunday, December 31, 1 BC."
   (let ((calendar-coptic-epoch calendar-ethiopic-epoch))
-    (calendar-coptic-to-absolute date)))
+    (calendar-coptic-to-absolute thedate)))
 
-(defun calendar-ethiopic-from-absolute (date)
+(defun calendar-ethiopic-from-absolute (thedate)
   "Compute the Ethiopic equivalent for absolute date DATE.
 The result is a list of the form (MONTH DAY YEAR).
 The absolute date is the number of days elapsed since the imaginary
 Gregorian date Sunday, December 31, 1 BC."
   (let ((calendar-coptic-epoch calendar-ethiopic-epoch))
-    (calendar-coptic-from-absolute date)))
+    (calendar-coptic-from-absolute thedate)))
 
 ;;;###cal-autoload
-(defun calendar-ethiopic-date-string (&optional date)
+(defun calendar-ethiopic-date-string (&optional thedate)
   "String of Ethiopic date of Gregorian DATE.
 Returns the empty string if DATE is pre-Ethiopic calendar.
 Defaults to today's date if DATE is not given."
   (let ((calendar-coptic-epoch calendar-ethiopic-epoch)
         (calendar-coptic-name calendar-ethiopic-name)
         (calendar-coptic-month-name-array calendar-ethiopic-month-name-array))
-    (calendar-coptic-date-string date)))
+    (calendar-coptic-date-string thedate)))
 
 ;;;###cal-autoload
 (defun calendar-ethiopic-print-date ()
@@ -229,8 +233,8 @@ Defaults to today's date if DATE is not given."
     (call-interactively 'calendar-coptic-print-date)))
 
 ;;;###cal-autoload
-(defun calendar-ethiopic-goto-date (date &optional noecho)
-  "Move cursor to Ethiopic date DATE.
+(defun calendar-ethiopic-goto-date (thedate &optional noecho)
+  "Move cursor to Ethiopic date THEDATE.
 Echo Ethiopic date unless NOECHO is t."
   (interactive
    (let ((calendar-coptic-epoch calendar-ethiopic-epoch)
@@ -238,7 +242,7 @@ Echo Ethiopic date unless NOECHO is t."
          (calendar-coptic-month-name-array calendar-ethiopic-month-name-array))
      (calendar-coptic-read-date)))
   (calendar-goto-date (calendar-gregorian-from-absolute
-                       (calendar-ethiopic-to-absolute date)))
+                       (calendar-ethiopic-to-absolute thedate)))
   (or noecho (calendar-ethiopic-print-date)))
 
 ;; To be called from diary-list-sexp-entries, where DATE is bound.
diff --git a/lisp/calendar/cal-french.el b/lisp/calendar/cal-french.el
index e759b5dad95..639bae700cc 100644
--- a/lisp/calendar/cal-french.el
+++ b/lisp/calendar/cal-french.el
@@ -1,4 +1,4 @@
-;;; cal-french.el --- calendar functions for the French Revolutionary calendar
+;;; cal-french.el --- calendar functions for the French Revolutionary calendar  -*- lexical-binding: t; -*-
 
 ;; Copyright (C) 1988-1989, 1992, 1994-1995, 1997, 2001-2021 Free
 ;; Software Foundation, Inc.
@@ -35,54 +35,45 @@
 (defconst calendar-french-epoch (calendar-absolute-from-gregorian '(9 22 1792))
   "Absolute date of start of French Revolutionary calendar = Sept 22, 1792.")
 
-(defconst calendar-french-month-name-array
-  ["Vende'miaire" "Brumaire" "Frimaire" "Nivo^se" "Pluvio^se" "Vento^se"
-   "Germinal" "Flore'al" "Prairial" "Messidor" "Thermidor" "Fructidor"]
-  "Array of month names in the French calendar.")
+(define-obsolete-variable-alias 'calendar-french-multibyte-month-name-array
+  'calendar-french-month-name-array "28.1")
 
-(defconst calendar-french-multibyte-month-name-array
+(defconst calendar-french-month-name-array
   ["Vendémiaire" "Brumaire" "Frimaire" "Nivôse" "Pluviôse" "Ventôse"
    "Germinal" "Floréal" "Prairial" "Messidor" "Thermidor" "Fructidor"]
-  "Array of multibyte month names in the French calendar.")
+  "Array of month names in the French calendar.")
 
 (defconst calendar-french-day-name-array
   ["Primidi" "Duodi" "Tridi" "Quartidi" "Quintidi" "Sextidi" "Septidi"
    "Octidi" "Nonidi" "Decadi"]
   "Array of day names in the French calendar.")
 
-(defconst calendar-french-special-days-array
-  ["de la Vertu" "du Ge'nie" "du Travail" "de la Raison" "des Re'compenses"
-   "de la Re'volution"]
-  "Array of special day names in the French calendar.")
+(define-obsolete-variable-alias 'calendar-french-multibyte-special-days-array
+  'calendar-french-special-days-array "28.1")
 
-(defconst calendar-french-multibyte-special-days-array
+(defconst calendar-french-special-days-array
   ["de la Vertu" "du Génie" "du Travail" "de la Raison" "des Récompenses"
    "de la Révolution"]
-  "Array of multibyte special day names in the French calendar.")
+  "Array of special day names in the French calendar.")
 
 (defun calendar-french-accents-p ()
-  "Return non-nil if diacritical marks are available."
-  (and (or window-system
-           (terminal-coding-system))
-       (or enable-multibyte-characters
-           (and (char-table-p standard-display-table)
-                (equal (aref standard-display-table 161) [161])))))
+  (declare (obsolete nil "28.1"))
+  t)
 
 (defun calendar-french-month-name-array ()
   "Return the array of month names, depending on whether accents are available."
-  (if (calendar-french-accents-p)
-      calendar-french-multibyte-month-name-array
-    calendar-french-month-name-array))
+  (declare (obsolete "use the variable of the same name instead" "28.1"))
+  calendar-french-month-name-array)
 
 (defun calendar-french-day-name-array ()
   "Return the array of day names."
+  (declare (obsolete "use the variable of the same name instead" "28.1"))
   calendar-french-day-name-array)
 
 (defun calendar-french-special-days-array ()
   "Return the special day names, depending on whether accents are available."
-  (if (calendar-french-accents-p)
-      calendar-french-multibyte-special-days-array
-    calendar-french-special-days-array))
+  (declare (obsolete "use the variable of the same name instead" "28.1"))
+  calendar-french-special-days-array)
 
 (defun calendar-french-leap-year-p (year)
   "True if YEAR is a leap year on the French Revolutionary calendar.
@@ -171,17 +162,13 @@ Defaults to today's date if DATE is not given."
          (d (calendar-extract-day french-date)))
     (cond
      ((< y 1) "")
-     ((= m 13) (format (if (calendar-french-accents-p)
-                           "Jour %s de l'Année %d de la Révolution"
-                         "Jour %s de l'Anne'e %d de la Re'volution")
-                       (aref (calendar-french-special-days-array) (1- d))
+     ((= m 13) (format "Jour %s de l'Année %d de la Révolution"
+                       (aref calendar-french-special-days-array (1- d))
                        y))
      (t (format
-         (if (calendar-french-accents-p)
-             "%d %s an %d de la Révolution"
-           "%d %s an %d de la Re'volution")
+         "%d %s an %d de la Révolution"
          d
-         (aref (calendar-french-month-name-array) (1- m))
+         (aref calendar-french-month-name-array (1- m))
          y)))))
 
 ;;;###cal-autoload
@@ -198,19 +185,16 @@ Defaults to today's date if DATE is not given."
   "Move cursor to French Revolutionary date DATE.
 Echo French Revolutionary date unless NOECHO is non-nil."
   (interactive
-   (let* ((months (calendar-french-month-name-array))
-          (special-days (calendar-french-special-days-array))
+   (let* ((months calendar-french-month-name-array)
+          (special-days calendar-french-special-days-array)
           (year (progn
-                  (calendar-read
-                   (if (calendar-french-accents-p)
-                       "Année de la Révolution (>0): "
-                     "Anne'e de la Re'volution (>0): ")
+                  (calendar-read-sexp
+                   "Année de la Révolution (>0)"
                    (lambda (x) (> x 0))
-                   (number-to-string
-                    (calendar-extract-year
-                     (calendar-french-from-absolute
-                      (calendar-absolute-from-gregorian
-                       (calendar-current-date))))))))
+                   (calendar-extract-year
+                    (calendar-french-from-absolute
+                     (calendar-absolute-from-gregorian
+                      (calendar-current-date)))))))
           (month-list
            (mapcar 'list
                    (append months
@@ -234,8 +218,8 @@ Echo French Revolutionary date unless NOECHO is non-nil."
                        (calendar-make-alist month-list 1 'car) t)))
           (day (if (> month 12)
                    (- month 12)
-                 (calendar-read
-                  "Jour (1-30): "
+                 (calendar-read-sexp
+                  "Jour (1-30)"
                   (lambda (x) (and (<= 1 x) (<= x 30))))))
           (month (if (> month 12) 13 month)))
      (list (list month day year))))
diff --git a/lisp/calendar/cal-hebrew.el b/lisp/calendar/cal-hebrew.el
index bcc80f0877b..50b4fc363bb 100644
--- a/lisp/calendar/cal-hebrew.el
+++ b/lisp/calendar/cal-hebrew.el
@@ -1,4 +1,4 @@
-;;; cal-hebrew.el --- calendar functions for the Hebrew calendar
+;;; cal-hebrew.el --- calendar functions for the Hebrew calendar  -*- lexical-binding: t; -*-
 
 ;; Copyright (C) 1995, 1997, 2001-2021 Free Software Foundation, Inc.
 
@@ -225,13 +225,12 @@ Driven by the variable `calendar-date-display-form'."
   "Interactively read the arguments for a Hebrew date command.
 Reads a year, month, and day."
   (let* ((today (calendar-current-date))
-         (year (calendar-read
-                "Hebrew calendar year (>3760): "
+         (year (calendar-read-sexp
+                "Hebrew calendar year (>3760)"
                 (lambda (x) (> x 3760))
-                (number-to-string
-                 (calendar-extract-year
-                  (calendar-hebrew-from-absolute
-                   (calendar-absolute-from-gregorian today))))))
+                (calendar-extract-year
+                 (calendar-hebrew-from-absolute
+                  (calendar-absolute-from-gregorian today)))))
          (month-array (if (calendar-hebrew-leap-year-p year)
                           calendar-hebrew-month-name-array-leap-year
                         calendar-hebrew-month-name-array-common-year))
@@ -258,10 +257,11 @@ Reads a year, month, and day."
          (last (calendar-hebrew-last-day-of-month month year))
          (first (if (and (= year 3761) (= month 10))
                     18 1))
-         (day (calendar-read
-               (format "Hebrew calendar day (%d-%d): "
-                       first last)
-               (lambda (x) (and (<= first x) (<= x last))))))
+         (day (calendar-read-sexp
+               "Hebrew calendar day (%d-%d)"
+               (lambda (x) (and (<= first x) (<= x last)))
+               nil
+               first last)))
     (list (list month day year))))
 
 ;;;###cal-autoload
@@ -399,19 +399,20 @@ is non-nil."
                      (list m (calendar-last-day-of-month m y) y))))))
            (abs-h (calendar-hebrew-to-absolute (list 9 25 h-y)))
            (ord ["first" "second" "third" "fourth" "fifth" "sixth"
-                 "seventh" "eighth"])
-           han)
+                 "seventh" "eighth"]))
       (holiday-filter-visible-calendar
        (if (or all calendar-hebrew-all-holidays-flag)
            (append
             (list
              (list (calendar-gregorian-from-absolute (1- abs-h))
                    "Erev Hanukkah"))
-            (dotimes (i 8 (nreverse han))
-              (push (list
-                     (calendar-gregorian-from-absolute (+ abs-h i))
-                     (format "Hanukkah (%s day)" (aref ord i)))
-                    han)))
+            (let (han)
+              (dotimes (i 8)
+                (push (list
+                       (calendar-gregorian-from-absolute (+ abs-h i))
+                       (format "Hanukkah (%s day)" (aref ord i)))
+                      han))
+              (nreverse han)))
          (list (list (calendar-gregorian-from-absolute abs-h) "Hanukkah")))))))
 
 ;;;###holiday-autoload
@@ -681,10 +682,10 @@ from the cursor position."
            (if (equal (current-buffer) (get-buffer calendar-buffer))
                (calendar-cursor-to-date t)
              (let* ((today (calendar-current-date))
-                    (year (calendar-read
-                           "Year of death (>0): "
+                    (year (calendar-read-sexp
+                           "Year of death (>0)"
                            (lambda (x) (> x 0))
-                           (number-to-string (calendar-extract-year today))))
+                           (calendar-extract-year today)))
                     (month-array calendar-month-name-array)
                     (completion-ignore-case t)
                     (month (cdr (assoc-string
@@ -694,20 +695,23 @@ from the cursor position."
                                   nil t)
                                  (calendar-make-alist month-array 1) t)))
                     (last (calendar-last-day-of-month month year))
-                    (day (calendar-read
-                          (format "Day of death (1-%d): " last)
-                          (lambda (x) (and (< 0 x) (<= x last))))))
+                    (day (calendar-read-sexp
+                          "Day of death (1-%d)"
+                          (lambda (x) (and (< 0 x) (<= x last)))
+                          nil
+                          last)))
                (list month day year))))
           (death-year (calendar-extract-year death-date))
-          (start-year (calendar-read
-                       (format "Starting year of Yahrzeit table (>%d): "
-                               death-year)
+          (start-year (calendar-read-sexp
+                       "Starting year of Yahrzeit table (>%d)"
                        (lambda (x) (> x death-year))
-                       (number-to-string (1+ death-year))))
-          (end-year (calendar-read
-                     (format "Ending year of Yahrzeit table (>=%d): "
-                             start-year)
-                     (lambda (x) (>= x start-year)))))
+                       (1+ death-year)
+                       death-year))
+          (end-year (calendar-read-sexp
+                     "Ending year of Yahrzeit table (>=%d)"
+                     (lambda (x) (>= x start-year))
+                     nil
+                     start-year)))
      (list death-date start-year end-year)))
   (message "Computing Yahrzeits...")
   (let* ((h-date (calendar-hebrew-from-absolute
diff --git a/lisp/calendar/cal-html.el b/lisp/calendar/cal-html.el
index 3d7cc938437..e5810c3f027 100644
--- a/lisp/calendar/cal-html.el
+++ b/lisp/calendar/cal-html.el
@@ -1,4 +1,4 @@
-;;; cal-html.el --- functions for printing HTML calendars
+;;; cal-html.el --- functions for printing HTML calendars  -*- lexical-binding: t; -*-
 
 ;; Copyright (C) 2002-2021 Free Software Foundation, Inc.
 
@@ -250,7 +250,7 @@ Contains links to previous and next month and year, and current minical."
                        calendar-week-start-day))
                7))
          (monthpage-name (cal-html-monthpage-name month year))
-         date)
+         ) ;; date
     ;; Start writing table.
     (insert (cal-html-comment "MINICAL")
             (cal-html-b-table "class=minical border=1 align=center"))
@@ -276,7 +276,7 @@ Contains links to previous and next month and year, and current minical."
           (insert cal-html-e-tablerow-string
                   cal-html-b-tablerow-string)))
     ;; End empty slots (for some browsers like konqueror).
-    (dotimes (i end-blank-days)
+    (dotimes (_ end-blank-days)
       (insert
        cal-html-b-tabledata-string
        cal-html-e-tabledata-string)))
@@ -431,12 +431,11 @@ holidays in HOLIDAY-LIST."
 ;;; User commands.
 
 ;;;###cal-autoload
-(defun cal-html-cursor-month (month year dir &optional event)
+(defun cal-html-cursor-month (month year dir &optional _event)
   "Write an HTML calendar file for numeric MONTH of four-digit YEAR.
 The output directory DIR is created if necessary.  Interactively,
-MONTH and YEAR are taken from the calendar cursor position, or from
-the position specified by EVENT.  Note that any existing output files
-are overwritten."
+MONTH and YEAR are taken from the calendar cursor position.
+Note that any existing output files are overwritten."
   (interactive (let* ((event last-nonmenu-event)
                       (date (calendar-cursor-to-date t event))
                       (month (calendar-extract-month date))
@@ -446,11 +445,11 @@ are overwritten."
   (cal-html-one-month month year dir))
 
 ;;;###cal-autoload
-(defun cal-html-cursor-year (year dir &optional event)
+(defun cal-html-cursor-year (year dir &optional _event)
   "Write HTML calendar files (index and monthly pages) for four-digit YEAR.
 The output directory DIR is created if necessary.  Interactively,
-YEAR is taken from the calendar cursor position, or from the position
-specified by EVENT.  Note that any existing output files are overwritten."
+YEAR is taken from the calendar cursor position.
+Note that any existing output files are overwritten."
   (interactive (let* ((event last-nonmenu-event)
                       (year (calendar-extract-year
                              (calendar-cursor-to-date t event))))
diff --git a/lisp/calendar/cal-islam.el b/lisp/calendar/cal-islam.el
index d256310ba6c..45c6ffa7bd7 100644
--- a/lisp/calendar/cal-islam.el
+++ b/lisp/calendar/cal-islam.el
@@ -1,4 +1,4 @@
-;;; cal-islam.el --- calendar functions for the Islamic calendar
+;;; cal-islam.el --- calendar functions for the Islamic calendar  -*- lexical-binding: t; -*-
 
 ;; Copyright (C) 1995, 1997, 2001-2021 Free Software Foundation, Inc.
 
@@ -67,8 +67,8 @@
   "Absolute date of Islamic DATE.
 The absolute date is the number of days elapsed since the (imaginary)
 Gregorian date Sunday, December 31, 1 BC."
-  (let* ((month (calendar-extract-month date))
-         (day (calendar-extract-day date))
+  (let* (;;(month (calendar-extract-month date))
+         ;;(day (calendar-extract-day date))
          (year (calendar-extract-year date))
          (y (% year 30))
          (leap-years-in-cycle (cond ((< y 3) 0)
@@ -143,13 +143,12 @@ Driven by the variable `calendar-date-display-form'."
   "Interactively read the arguments for an Islamic date command.
 Reads a year, month, and day."
   (let* ((today (calendar-current-date))
-         (year (calendar-read
-                "Islamic calendar year (>0): "
+         (year (calendar-read-sexp
+                "Islamic calendar year (>0)"
                 (lambda (x) (> x 0))
-                (number-to-string
-                 (calendar-extract-year
-                  (calendar-islamic-from-absolute
-                   (calendar-absolute-from-gregorian today))))))
+                (calendar-extract-year
+                 (calendar-islamic-from-absolute
+                  (calendar-absolute-from-gregorian today)))))
          (month-array calendar-islamic-month-name-array)
          (completion-ignore-case t)
          (month (cdr (assoc-string
@@ -159,9 +158,11 @@ Reads a year, month, and day."
                        nil t)
                       (calendar-make-alist month-array 1) t)))
          (last (calendar-islamic-last-day-of-month month year))
-         (day (calendar-read
-               (format "Islamic calendar day (1-%d): " last)
-               (lambda (x) (and (< 0 x) (<= x last))))))
+         (day (calendar-read-sexp
+               "Islamic calendar day (1-%d)"
+               (lambda (x) (and (< 0 x) (<= x last)))
+               nil
+               last)))
     (list (list month day year))))
 
 ;;;###cal-autoload
diff --git a/lisp/calendar/cal-iso.el b/lisp/calendar/cal-iso.el
index 956433e4a20..90f57c25e9d 100644
--- a/lisp/calendar/cal-iso.el
+++ b/lisp/calendar/cal-iso.el
@@ -1,4 +1,4 @@
-;;; cal-iso.el --- calendar functions for the ISO calendar
+;;; cal-iso.el --- calendar functions for the ISO calendar  -*- lexical-binding: t; -*-
 
 ;; Copyright (C) 1995, 1997, 2001-2021 Free Software Foundation, Inc.
 
@@ -92,22 +92,23 @@ date Sunday, December 31, 1 BC."
   "Interactively read the arguments for an ISO date command.
 Reads a year and week, and if DAYFLAG is non-nil a day (otherwise
 taken to be 1)."
-  (let* ((year (calendar-read
-                "ISO calendar year (>0): "
+  (let* ((year (calendar-read-sexp
+                "ISO calendar year (>0)"
                 (lambda (x) (> x 0))
-                (number-to-string (calendar-extract-year
-                                (calendar-current-date)))))
+                (calendar-extract-year (calendar-current-date))))
          (no-weeks (calendar-extract-month
                     (calendar-iso-from-absolute
                      (1-
                       (calendar-dayname-on-or-before
                        1 (calendar-absolute-from-gregorian
                           (list 1 4 (1+ year))))))))
-         (week (calendar-read
-                (format "ISO calendar week (1-%d): " no-weeks)
-                (lambda (x) (and (> x 0) (<= x no-weeks)))))
-         (day (if dayflag (calendar-read
-                           "ISO day (1-7): "
+         (week (calendar-read-sexp
+                "ISO calendar week (1-%d)"
+                (lambda (x) (and (> x 0) (<= x no-weeks)))
+                nil
+                no-weeks))
+         (day (if dayflag (calendar-read-sexp
+                           "ISO day (1-7)"
                            (lambda (x) (and (<= 1 x) (<= x 7))))
                 1)))
     (list (list week day year))))
diff --git a/lisp/calendar/cal-julian.el b/lisp/calendar/cal-julian.el
index 235b4d00900..47880a4e974 100644
--- a/lisp/calendar/cal-julian.el
+++ b/lisp/calendar/cal-julian.el
@@ -95,14 +95,13 @@ Driven by the variable `calendar-date-display-form'."
   "Move cursor to Julian DATE; echo Julian date unless NOECHO is non-nil."
   (interactive
    (let* ((today (calendar-current-date))
-          (year (calendar-read
-                 "Julian calendar year (>0): "
+          (year (calendar-read-sexp
+                 "Julian calendar year (>0)"
                  (lambda (x) (> x 0))
-                 (number-to-string
-                  (calendar-extract-year
-                   (calendar-julian-from-absolute
-                    (calendar-absolute-from-gregorian
-                     today))))))
+                 (calendar-extract-year
+                  (calendar-julian-from-absolute
+                   (calendar-absolute-from-gregorian
+                    today)))))
           (month-array calendar-month-name-array)
           (completion-ignore-case t)
           (month (cdr (assoc-string
@@ -115,12 +114,13 @@ Driven by the variable `calendar-date-display-form'."
            (if (and (zerop (% year 4)) (= month 2))
                29
              (aref [31 28 31 30 31 30 31 31 30 31 30 31] (1- month))))
-          (day (calendar-read
-                (format "Julian calendar day (%d-%d): "
-                        (if (and (= year 1) (= month 1)) 3 1) last)
+          (day (calendar-read-sexp
+                "Julian calendar day (%d-%d)"
                 (lambda (x)
                   (and (< (if (and (= year 1) (= month 1)) 2 0) x)
-                       (<= x last))))))
+                       (<= x last)))
+                nil
+                (if (and (= year 1) (= month 1)) 3 1) last)))
      (list (list month day year))))
   (calendar-goto-date (calendar-gregorian-from-absolute
                        (calendar-julian-to-absolute date)))
@@ -173,8 +173,8 @@ Defaults to today's date if DATE is not given."
 (defun calendar-astro-goto-day-number (daynumber &optional noecho)
   "Move cursor to astronomical (Julian) DAYNUMBER.
 Echo astronomical (Julian) day number unless NOECHO is non-nil."
-  (interactive (list (calendar-read
-                      "Astronomical (Julian) day number (>1721425): "
+  (interactive (list (calendar-read-sexp
+                      "Astronomical (Julian) day number (>1721425)"
                       (lambda (x) (> x 1721425)))))
   (calendar-goto-date
    (calendar-gregorian-from-absolute
diff --git a/lisp/calendar/cal-mayan.el b/lisp/calendar/cal-mayan.el
index 8d894ebd986..9a221921130 100644
--- a/lisp/calendar/cal-mayan.el
+++ b/lisp/calendar/cal-mayan.el
@@ -1,4 +1,4 @@
-;;; cal-mayan.el --- calendar functions for the Mayan calendars
+;;; cal-mayan.el --- calendar functions for the Mayan calendars  -*- lexical-binding: t; -*-
 
 ;; Copyright (C) 1992-1993, 1995, 1997, 2001-2021 Free Software
 ;; Foundation, Inc.
@@ -135,8 +135,8 @@ but some use 1137140.  Using 1232041 gives you Spinden's correlation; using
 (defun calendar-mayan-read-haab-date ()
   "Prompt for a Mayan haab date."
   (let* ((completion-ignore-case t)
-         (haab-day (calendar-read
-                    "Haab kin (0-19): "
+         (haab-day (calendar-read-sexp
+                    "Haab kin (0-19)"
                     (lambda (x) (and (>= x 0) (< x 20)))))
          (haab-month-list (append calendar-mayan-haab-month-name-array
                                   (and (< haab-day 5) '("Uayeb"))))
@@ -151,8 +151,8 @@ but some use 1137140.  Using 1232041 gives you Spinden's correlation; using
 (defun calendar-mayan-read-tzolkin-date ()
   "Prompt for a Mayan tzolkin date."
   (let* ((completion-ignore-case t)
-         (tzolkin-count (calendar-read
-                         "Tzolkin kin (1-13): "
+         (tzolkin-count (calendar-read-sexp
+                         "Tzolkin kin (1-13)"
                          (lambda (x) (and (> x 0) (< x 14)))))
          (tzolkin-name-list (append calendar-mayan-tzolkin-names-array nil))
          (tzolkin-name (cdr
diff --git a/lisp/calendar/cal-menu.el b/lisp/calendar/cal-menu.el
index a30c681a897..497f3329055 100644
--- a/lisp/calendar/cal-menu.el
+++ b/lisp/calendar/cal-menu.el
@@ -1,4 +1,4 @@
-;;; cal-menu.el --- calendar functions for menu bar and popup menu support
+;;; cal-menu.el --- calendar functions for menu bar and popup menu support  -*- lexical-binding: t; -*-
 
 ;; Copyright (C) 1994-1995, 2001-2021 Free Software Foundation, Inc.
 
@@ -183,6 +183,8 @@ Signals an error if popups are unavailable."
 ;; Autoloaded in diary-lib.
 (declare-function calendar-check-holidays "holidays" (date))
 
+(defvar diary-list-include-blanks)
+
 (defun calendar-mouse-view-diary-entries (&optional date diary event)
   "Pop up menu of diary entries for mouse-selected date.
 Use optional DATE and alternative file DIARY.  EVENT is the event
diff --git a/lisp/calendar/cal-move.el b/lisp/calendar/cal-move.el
index 710ce37ccbf..9294362cb43 100644
--- a/lisp/calendar/cal-move.el
+++ b/lisp/calendar/cal-move.el
@@ -1,4 +1,4 @@
-;;; cal-move.el --- calendar functions for movement in the calendar
+;;; cal-move.el --- calendar functions for movement in the calendar  -*- lexical-binding: t; -*-
 
 ;; Copyright (C) 1995, 2001-2021 Free Software Foundation, Inc.
 
@@ -386,15 +386,16 @@ Moves forward if ARG is negative."
   "Move cursor to YEAR, DAY number; echo DAY/YEAR unless NOECHO is non-nil.
 Negative DAY counts backward from end of year."
   (interactive
-   (let* ((year (calendar-read
-                 "Year (>0): "
+   (let* ((year (calendar-read-sexp
+                 "Year (>0)"
                  (lambda (x) (> x 0))
-                 (number-to-string (calendar-extract-year
-                                 (calendar-current-date)))))
+                 (calendar-extract-year (calendar-current-date))))
           (last (if (calendar-leap-year-p year) 366 365))
-          (day (calendar-read
-                (format "Day number (+/- 1-%d): " last)
-                (lambda (x) (and (<= 1 (abs x)) (<= (abs x) last))))))
+          (day (calendar-read-sexp
+                "Day number (+/- 1-%d)"
+                (lambda (x) (and (<= 1 (abs x)) (<= (abs x) last)))
+                nil
+                last)))
      (list year day)))
   (calendar-goto-date
    (calendar-gregorian-from-absolute
diff --git a/lisp/calendar/cal-persia.el b/lisp/calendar/cal-persia.el
index a9c99fedbdb..ca37d803224 100644
--- a/lisp/calendar/cal-persia.el
+++ b/lisp/calendar/cal-persia.el
@@ -1,4 +1,4 @@
-;;; cal-persia.el --- calendar functions for the Persian calendar
+;;; cal-persia.el --- calendar functions for the Persian calendar  -*- lexical-binding: t; -*-
 
 ;; Copyright (C) 1996-1997, 2001-2021 Free Software Foundation, Inc.
 
@@ -139,13 +139,14 @@ Gregorian date Sunday, December 31, 1 BC."
                         (calendar-absolute-from-gregorian
                          (or date (calendar-current-date)))))
          (y (calendar-extract-year persian-date))
-         (m (calendar-extract-month persian-date))
-         (monthname (aref calendar-persian-month-name-array (1- m)))
+         (m (calendar-extract-month persian-date)))
+    (calendar-dlet*
+        ((monthname (aref calendar-persian-month-name-array (1- m)))
          (day (number-to-string (calendar-extract-day persian-date)))
          (year (number-to-string y))
          (month (number-to-string m))
          dayname)
-    (mapconcat 'eval calendar-date-display-form "")))
+      (mapconcat #'eval calendar-date-display-form ""))))
 
 ;;;###cal-autoload
 (defun calendar-persian-print-date ()
@@ -157,14 +158,13 @@ Gregorian date Sunday, December 31, 1 BC."
 (defun calendar-persian-read-date ()
   "Interactively read the arguments for a Persian date command.
 Reads a year, month, and day."
-  (let* ((year (calendar-read
-                "Persian calendar year (not 0): "
+  (let* ((year (calendar-read-sexp
+                "Persian calendar year (not 0)"
                 (lambda (x) (not (zerop x)))
-                (number-to-string
-                 (calendar-extract-year
-                  (calendar-persian-from-absolute
-                   (calendar-absolute-from-gregorian
-                    (calendar-current-date)))))))
+                (calendar-extract-year
+                 (calendar-persian-from-absolute
+                  (calendar-absolute-from-gregorian
+                   (calendar-current-date))))))
          (completion-ignore-case t)
          (month (cdr (assoc
                       (completing-read
@@ -175,9 +175,11 @@ Reads a year, month, and day."
                       (calendar-make-alist calendar-persian-month-name-array
                                            1))))
          (last (calendar-persian-last-day-of-month month year))
-         (day (calendar-read
-               (format "Persian calendar day (1-%d): " last)
-               (lambda (x) (and (< 0 x) (<= x last))))))
+         (day (calendar-read-sexp
+               "Persian calendar day (1-%d)"
+               (lambda (x) (and (< 0 x) (<= x last)))
+               nil
+               last)))
     (list (list month day year))))
 
 ;;;###cal-autoload
diff --git a/lisp/calendar/cal-tex.el b/lisp/calendar/cal-tex.el
index 9df9f4cbedf..f5932014dd9 100644
--- a/lisp/calendar/cal-tex.el
+++ b/lisp/calendar/cal-tex.el
@@ -1,4 +1,4 @@
-;;; cal-tex.el --- calendar functions for printing calendars with LaTeX
+;;; cal-tex.el --- calendar functions for printing calendars with LaTeX  -*- lexical-binding: t; -*-
 
 ;; Copyright (C) 1995, 2001-2021 Free Software Foundation, Inc.
 
@@ -248,6 +248,8 @@ This definition is the heart of the calendar!")
 
 (autoload 'diary-list-entries "diary-lib")
 
+(defvar diary-list-include-blanks)
+
 (defun cal-tex-list-diary-entries (d1 d2)
   "Generate a list of all diary-entries from absolute date D1 to D2."
   (let (diary-list-include-blanks)
@@ -591,6 +593,8 @@ indicates a buffer position to use instead of point."
 LaTeX commands are inserted for the days of the MONTH in YEAR.
 Diary entries on DIARY-LIST are included.  Holidays on HOLIDAYS
 are included.  Each day is formatted using format DAY-FORMAT."
+  (with-suppressed-warnings ((lexical date))
+    (defvar date))                      ;For `cal-tex-daily-string'.
   (let ((blank-days                     ; at start of month
          (mod
           (- (calendar-day-of-week (list month 1 year))
@@ -605,7 +609,7 @@ are included.  Each day is formatted using format DAY-FORMAT."
         (insert (format day-format (cal-tex-month-name month) j))
         (cal-tex-arg (cal-tex-latexify-list diary-list date))
         (cal-tex-arg (cal-tex-latexify-list holidays date))
-        (cal-tex-arg (eval cal-tex-daily-string))
+        (cal-tex-arg (eval cal-tex-daily-string t))
         (cal-tex-arg)
         (cal-tex-comment))
       (when (and (zerop (mod (+ j blank-days) 7))
@@ -885,13 +889,15 @@ argument EVENT specifies a different buffer position."
   (interactive (list (prefix-numeric-value current-prefix-arg)
                      last-nonmenu-event))
   (or n (setq n 1))
+  (with-suppressed-warnings ((lexical date))
+    (defvar date))                      ;For `cal-tex-daily-string'.
   (let* ((date (calendar-gregorian-from-absolute
                 (calendar-dayname-on-or-before
                  1
                  (calendar-absolute-from-gregorian
                   (calendar-cursor-to-date t event)))))
          (month (calendar-extract-month date))
-         (year (calendar-extract-year date))
+         ;; (year (calendar-extract-year date))
          (day (calendar-extract-day date))
          (d1 (calendar-absolute-from-gregorian date))
          (d2 (+ (* 7 n) d1))
@@ -932,7 +938,7 @@ argument EVENT specifies a different buffer position."
           (insert ": ")
           (cal-tex-large-bf s))
         (cal-tex-hfill)
-        (insert " " (eval cal-tex-daily-string))
+        (insert " " (eval cal-tex-daily-string t))
         (cal-tex-e-parbox)
         (cal-tex-nl)
         (cal-tex-noindent)
@@ -951,7 +957,8 @@ argument EVENT specifies a different buffer position."
         (cal-tex-e-parbox "2cm")
         (cal-tex-nl)
         (setq month (calendar-extract-month date)
-              year (calendar-extract-year date)))
+              ;; year (calendar-extract-year date)
+              ))
       (cal-tex-e-parbox)
       (unless (= i (1- n))
         (run-hooks 'cal-tex-week-hook)
@@ -961,13 +968,16 @@ argument EVENT specifies a different buffer position."
 
 ;; TODO respect cal-tex-daily-start,end?
 ;; Using different numbers of hours will probably break some layouts.
-(defun cal-tex-week-hours (date holidays height)
-  "Insert hourly entries for DATE with HOLIDAYS, with line height HEIGHT.
+(defun cal-tex-week-hours (thedate holidays height)
+  "Insert hourly entries for THEDATE with HOLIDAYS, with line height HEIGHT.
 Uses the 24-hour clock if `cal-tex-24' is non-nil.  Note that the hours
 shown are hard-coded to 8-12, 13-17."
-  (let ((month (calendar-extract-month date))
+  (with-suppressed-warnings ((lexical date))
+    (defvar date))                      ;For `cal-tex-daily-string'.
+  (let ((date thedate)
+        (month (calendar-extract-month date))
         (day (calendar-extract-day date))
-        (year (calendar-extract-year date))
+        ;; (year (calendar-extract-year date))
         morning afternoon s)
   (cal-tex-comment "begin cal-tex-week-hours")
   (cal-tex-cmd  "\\ \\\\[-.2cm]")
@@ -983,7 +993,7 @@ shown are hard-coded to 8-12, 13-17."
     (insert ": ")
     (cal-tex-large-bf s))
   (cal-tex-hfill)
-  (insert " " (eval cal-tex-daily-string))
+  (insert " " (eval cal-tex-daily-string t))
   (cal-tex-e-parbox)
   (cal-tex-nl "-.3cm")
   (cal-tex-rule "0pt" "6.8in" ".2mm")
@@ -1088,14 +1098,16 @@ shown are hard-coded to 8-12, 13-17."
 (defun cal-tex-weekly-common (n event &optional filofax)
   "Common code for weekly calendars."
   (or n (setq n 1))
+  (with-suppressed-warnings ((lexical date))
+    (defvar date))                      ;For `cal-tex-daily-string'.
   (let* ((date (calendar-gregorian-from-absolute
                 (calendar-dayname-on-or-before
                  1
                  (calendar-absolute-from-gregorian
                   (calendar-cursor-to-date t event)))))
-         (month (calendar-extract-month date))
-         (year (calendar-extract-year date))
-         (day (calendar-extract-day date))
+         ;; (month (calendar-extract-month date))
+         ;; (year (calendar-extract-year date))
+         ;; (day (calendar-extract-day date))
          (d1 (calendar-absolute-from-gregorian date))
          (d2 (+ (* 7 n) d1))
          (holidays (if cal-tex-holidays
@@ -1161,7 +1173,7 @@ shown are hard-coded to 8-12, 13-17."
         (cal-tex-arg (number-to-string (calendar-extract-day date)))
         (cal-tex-arg (cal-tex-latexify-list diary-list date))
         (cal-tex-arg (cal-tex-latexify-list holidays date))
-        (cal-tex-arg (eval cal-tex-daily-string))
+        (cal-tex-arg (eval cal-tex-daily-string t))
         (insert "%\n")
         (setq date (cal-tex-incr-date date)))
       (insert "\\noindent\\rule{\\textwidth}{0.3pt}\\\\%\n")
@@ -1258,14 +1270,16 @@ Optional EVENT indicates a buffer position to use instead of point."
   (interactive (list (prefix-numeric-value current-prefix-arg)
                      last-nonmenu-event))
   (or n (setq n 1))
+  (with-suppressed-warnings ((lexical date))
+    (defvar date))                      ;For `cal-tex-daily-string'.
   (let* ((date (calendar-gregorian-from-absolute
                 (calendar-dayname-on-or-before
                  calendar-week-start-day
                  (calendar-absolute-from-gregorian
                   (calendar-cursor-to-date t event)))))
-         (month (calendar-extract-month date))
-         (year (calendar-extract-year date))
-         (day (calendar-extract-day date))
+         ;; (month (calendar-extract-month date))
+         ;; (year (calendar-extract-year date))
+         ;; (day (calendar-extract-day date))
          (d1 (calendar-absolute-from-gregorian date))
          (d2 (+ (* 7 n) d1))
          (holidays (if cal-tex-holidays
@@ -1311,7 +1325,7 @@ Optional EVENT indicates a buffer position to use instead of point."
         (cal-tex-arg (number-to-string (calendar-extract-day date)))
         (cal-tex-arg (cal-tex-latexify-list diary-list date))
         (cal-tex-arg (cal-tex-latexify-list holidays date))
-        (cal-tex-arg (eval cal-tex-daily-string))
+        (cal-tex-arg (eval cal-tex-daily-string t))
         (insert "%\n")
         (setq date (cal-tex-incr-date date)))
       (unless (= i (1- n))
@@ -1342,14 +1356,16 @@ Optional EVENT indicates a buffer position to use instead of point."
   (interactive (list (prefix-numeric-value current-prefix-arg)
                      last-nonmenu-event))
   (or n (setq n 1))
+  (with-suppressed-warnings ((lexical date))
+    (defvar date))                      ;For `cal-tex-daily-string'.
   (let* ((date (calendar-gregorian-from-absolute
                 (calendar-dayname-on-or-before
                  1
                  (calendar-absolute-from-gregorian
                   (calendar-cursor-to-date t event)))))
-         (month (calendar-extract-month date))
-         (year (calendar-extract-year date))
-         (day (calendar-extract-day date))
+         ;; (month (calendar-extract-month date))
+         ;; (year (calendar-extract-year date))
+         ;; (day (calendar-extract-day date))
          (d1 (calendar-absolute-from-gregorian date))
          (d2 (+ (* 7 n) d1))
          (holidays (if cal-tex-holidays
@@ -1383,11 +1399,11 @@ Optional EVENT indicates a buffer position to use instead of point."
                     "\\leftday")))
         (cal-tex-arg (cal-tex-latexify-list diary-list date))
         (cal-tex-arg (cal-tex-latexify-list holidays date "\\\\" t))
-        (cal-tex-arg (eval cal-tex-daily-string))
+        (cal-tex-arg (eval cal-tex-daily-string t))
         (insert "%\n")
-        (if cal-tex-rules
-            (insert "\\linesfill\n")
-          (insert "\\vfill\\noindent\\rule{\\textwidth}{0.3pt}\\\\%\n"))
+        (insert (if cal-tex-rules
+                    "\\linesfill\n"
+                  "\\vfill\\noindent\\rule{\\textwidth}{0.3pt}\\\\%\n"))
         (cal-tex-newpage)
         (setq date (cal-tex-incr-date date)))
       (insert "%\n")
@@ -1397,11 +1413,11 @@ Optional EVENT indicates a buffer position to use instead of point."
         (insert "\\weekend")
         (cal-tex-arg (cal-tex-latexify-list diary-list date))
         (cal-tex-arg (cal-tex-latexify-list holidays date "\\\\" t))
-        (cal-tex-arg (eval cal-tex-daily-string))
+        (cal-tex-arg (eval cal-tex-daily-string t))
         (insert "%\n")
-        (if cal-tex-rules
-            (insert "\\linesfill\n")
-          (insert "\\vfill"))
+        (insert (if cal-tex-rules
+                    "\\linesfill\n"
+                  "\\vfill"))
         (setq date (cal-tex-incr-date date)))
       (or cal-tex-rules
           (insert "\\noindent\\rule{\\textwidth}{0.3pt}\\\\%\n"))
@@ -1442,12 +1458,15 @@ a buffer position to use instead of point."
     (cal-tex-end-document)
     (run-hooks 'cal-tex-hook)))
 
-(defun cal-tex-daily-page (date)
-  "Make a calendar page for Gregorian DATE on 8.5 by 11 paper.
+(defun cal-tex-daily-page (thedate)
+  "Make a calendar page for Gregorian THEDATE on 8.5 by 11 paper.
 Uses the 24-hour clock if `cal-tex-24' is non-nil.  Produces
 hourly sections for the period specified by `cal-tex-daily-start'
 and `cal-tex-daily-end'."
-  (let ((month-name (cal-tex-month-name (calendar-extract-month date)))
+  (with-suppressed-warnings ((lexical date))
+    (defvar date))                      ;For `cal-tex-daily-string'.
+  (let ((date thedate)
+        (month-name (cal-tex-month-name (calendar-extract-month date)))
         (i (1- cal-tex-daily-start))
         hour)
     (cal-tex-banner "cal-tex-daily-page")
@@ -1459,7 +1478,7 @@ and `cal-tex-daily-end'."
     (cal-tex-bf month-name )
     (cal-tex-e-parbox)
     (cal-tex-hspace "1cm")
-    (cal-tex-scriptsize (eval cal-tex-daily-string))
+    (cal-tex-scriptsize (eval cal-tex-daily-string t))
     (cal-tex-hspace "3.5cm")
     (cal-tex-e-makebox)
     (cal-tex-hfill)
diff --git a/lisp/calendar/cal-x.el b/lisp/calendar/cal-x.el
index 1c19a60db10..ca303ce39ae 100644
--- a/lisp/calendar/cal-x.el
+++ b/lisp/calendar/cal-x.el
@@ -1,4 +1,4 @@
-;;; cal-x.el --- calendar windows in dedicated frames
+;;; cal-x.el --- calendar windows in dedicated frames  -*- lexical-binding: t; -*-
 
 ;; Copyright (C) 1994-1995, 2001-2021 Free Software Foundation, Inc.
 
diff --git a/lisp/calendar/calendar.el b/lisp/calendar/calendar.el
index 21cea212e18..3f9fe1c9d8f 100644
--- a/lisp/calendar/calendar.el
+++ b/lisp/calendar/calendar.el
@@ -112,6 +112,8 @@
 
 ;;; Code:
 
+(eval-when-compile (require 'subr-x))
+
 (load "cal-loaddefs" nil t)
 
 ;; Calendar has historically relied heavily on dynamic scoping.
@@ -1459,7 +1461,7 @@ Optional integers MON and YR are used instead of today's date."
 Inserts STRING so that it ends at INDENT.  STRING is either a
 literal string, or a sexp to evaluate to return such.  Truncates
 STRING to length TRUNCATE, and ensures a trailing space."
-  (if (not (ignore-errors (stringp (setq string (eval string)))))
+  (if (not (ignore-errors (stringp (setq string (eval string t)))))
       (calendar-move-to-column indent)
     (if (> (string-width string) truncate)
         (setq string (truncate-string-to-width string truncate)))
@@ -1526,7 +1528,7 @@ first INDENT characters on the line."
               (format (format "%%%dd" calendar-day-digit-width) day)
               'mouse-face 'highlight
               'help-echo (calendar-dlet* ((day day) (month month) (year year))
-                           (eval calendar-date-echo-text))
+                           (eval calendar-date-echo-text t))
               ;; 'date property prevents intermonth text confusing re-searches.
               ;; (Tried intangible, it did not really work.)
               'date t)
@@ -2054,23 +2056,40 @@ With argument ARG, jump to mark, pop it, and put point at end of ring."
   (error "%s not available in the calendar"
          (global-key-binding (this-command-keys))))
 
+(defun calendar-read-sexp (prompt predicate &optional default &rest args)
+  "Return an object read from the minibuffer.
+Passes PROMPT, DEFAULT, and ARGS to `format-prompt' to build
+the actual prompt.  PREDICATE is called with a single value (the object
+the user entered) and it should return non-nil if that value is a valid choice.
+DEFAULT is the default value to use."
+  (unless (stringp default) (setq default (format "%S" default)))
+  (named-let query ()
+    ;; The call to `read-from-minibuffer' is copied from `read-minibuffer',
+    ;; except it's changed to use the DEFAULT arg instead of INITIAL-CONTENTS.
+    (let ((value (read-from-minibuffer
+                  (apply #'format-prompt prompt default args)
+                  nil minibuffer-local-map t 'minibuffer-history default)))
+      (if (funcall predicate value)
+          value
+        (query)))))
+
 (defun calendar-read (prompt acceptable &optional initial-contents)
   "Return an object read from the minibuffer.
 Prompt with the string PROMPT and use the function ACCEPTABLE to decide
 if entered item is acceptable.  If non-nil, optional third arg
 INITIAL-CONTENTS is a string to insert in the minibuffer before reading."
+  (declare (obsolete calendar-read-sexp "28.1"))
   (let ((value (read-minibuffer prompt initial-contents)))
     (while (not (funcall acceptable value))
       (setq value (read-minibuffer prompt initial-contents)))
     value))
 
-
 (defun calendar-customized-p (symbol)
   "Return non-nil if SYMBOL has been customized."
   (and (default-boundp symbol)
        (let ((standard (get symbol 'standard-value)))
          (and standard
-              (not (equal (eval (car standard)) (default-value symbol)))))))
+              (not (equal (eval (car standard) t) (default-value symbol)))))))
 
 (defun calendar-abbrev-construct (full &optional maxlen)
   "From sequence FULL, return a vector of abbreviations.
@@ -2284,32 +2303,38 @@ arguments SEQUENCES."
           (append (list sequence) sequences))
     (reverse alist)))
 
-(defun calendar-read-date (&optional noday)
+(defun calendar-read-date (&optional noday default-date)
   "Prompt for Gregorian date.  Return a list (month day year).
 If optional NODAY is t, does not ask for day, but just returns
 \(month 1 year); if NODAY is any other non-nil value the value
 returned is (month year)."
-  (let* ((year (calendar-read
-                "Year (>0): "
-                (lambda (x) (> x 0))
-                (number-to-string (calendar-extract-year
-                                (calendar-current-date)))))
+  (unless default-date (setq default-date (calendar-current-date)))
+  (let* ((defyear (calendar-extract-year default-date))
+         (year (calendar-read-sexp "Year (>0)"
+                                   (lambda (x) (> x 0))
+                                   defyear))
          (month-array calendar-month-name-array)
+         (defmon (aref month-array (1- (calendar-extract-month default-date))))
          (completion-ignore-case t)
          (month (cdr (assoc-string
-                       (completing-read
-                        "Month name: "
-                        (mapcar #'list (append month-array nil))
-                        nil t)
+                      (completing-read
+                       (format-prompt "Month name" defmon)
+                       (append month-array nil)
+                       nil t nil nil defmon)
                       (calendar-make-alist month-array 1) t)))
+         (defday (calendar-extract-day default-date))
          (last (calendar-last-day-of-month month year)))
     (if noday
         (if (eq noday t)
             (list month 1 year)
           (list month year))
       (list month
-            (calendar-read (format "Day (1-%d): " last)
-                           (lambda (x) (and (< 0 x) (<= x last))))
+            (calendar-read-sexp "Day (1-%d)"
+                                (lambda (x) (and (< 0 x) (<= x last)))
+                                ;; Don't offer today's day as default
+                                ;; if it's not valid for the chosen
+                                ;; month/year.
+                                (if (<= defday last) defday) last)
             year))))
 
 (defun calendar-interval (mon1 yr1 mon2 yr2)
diff --git a/lisp/calendar/diary-lib.el b/lisp/calendar/diary-lib.el
index aad70161f9f..4efa3669967 100644
--- a/lisp/calendar/diary-lib.el
+++ b/lisp/calendar/diary-lib.el
@@ -2221,8 +2221,8 @@ Prefix argument ARG makes the entry nonmarking."
     (diary-make-entry
      (format "%s(diary-cyclic %d %s)"
              diary-sexp-entry-symbol
-             (calendar-read "Repeat every how many days: "
-                            (lambda (x) (> x 0)))
+             (calendar-read-sexp "Repeat every how many days"
+                                 (lambda (x) (> x 0)))
              (calendar-date-string (calendar-cursor-to-date t) nil t))
      arg)))
 
diff --git a/lisp/calendar/holidays.el b/lisp/calendar/holidays.el
index 932993beba0..4bc17de3067 100644
--- a/lisp/calendar/holidays.el
+++ b/lisp/calendar/holidays.el
@@ -423,16 +423,15 @@ of a holiday list.
 
 The optional LABEL is used to label the buffer created."
   (interactive
-   (let* ((start-year (calendar-read
-                       "Starting year of holidays (>0): "
+   (let* ((start-year (calendar-read-sexp
+                       "Starting year of holidays (>0)"
                        (lambda (x) (> x 0))
-                       (number-to-string (calendar-extract-year
-                                       (calendar-current-date)))))
-          (end-year (calendar-read
-                     (format "Ending year (inclusive) of holidays (>=%s): "
-                             start-year)
+                       (calendar-extract-year (calendar-current-date))))
+          (end-year (calendar-read-sexp
+                     "Ending year (inclusive) of holidays (>=%s)"
                      (lambda (x) (>= x start-year))
-                     (number-to-string start-year)))
+                     start-year
+                     start-year))
           (completion-ignore-case t)
           (lists
            (list
diff --git a/lisp/cedet/ede/base.el b/lisp/cedet/ede/base.el
index 7799746e0c4..810d6ef3bd4 100644
--- a/lisp/cedet/ede/base.el
+++ b/lisp/cedet/ede/base.el
@@ -160,16 +160,13 @@ and querying them will cause the actual project to get loaded.")
 ;; Projects can also affect how EDE works, by changing what appears in
 ;; the EDE menu, or how some keys are bound.
 ;;
-(unless (fboundp 'ede-target-list-p)
-  (cl-deftype ede-target-list () '(list-of ede-target)))
-
 (defclass ede-project (ede-project-placeholder)
   ((subproj :initform nil
             :type list
             :documentation "Sub projects controlled by this project.
 For Automake based projects, each directory is treated as a project.")
    (targets :initarg :targets
-            :type ede-target-list
+            :type (list-of ede-target)
             :custom (repeat (object :objectcreatefcn ede-new-target-custom))
             :label "Local Targets"
             :group (targets)
diff --git a/lisp/cedet/ede/proj.el b/lisp/cedet/ede/proj.el
index 59628ebf4c9..4af8b4104f5 100644
--- a/lisp/cedet/ede/proj.el
+++ b/lisp/cedet/ede/proj.el
@@ -184,7 +184,7 @@ Target variables are always renamed such as foo_CFLAGS, then included into
 commands where the variable would usually appear.")
    (rules :initarg :rules
           :initform nil
-          :type list
+          :type (list-of ede-makefile-rule)
           :custom (repeat (object :objecttype ede-makefile-rule))
           :label "Additional Rules"
           :group (make)
diff --git a/lisp/comint.el b/lisp/comint.el
index 53153af7d27..e52d67d0e50 100644
--- a/lisp/comint.el
+++ b/lisp/comint.el
@@ -3863,7 +3863,11 @@ REGEXP-GROUP is the regular expression group in REGEXP to use."
         (push (buffer-substring-no-properties
                (match-beginning regexp-group)
                (match-end regexp-group))
-              results))
+              results)
+        (when (zerop (length (match-string 0)))
+          ;; If the regexp can be empty (for instance, "^.*$"), we
+          ;; don't advance, so ensure forward progress.
+          (forward-line 1)))
       (nreverse results))))
 
 ;; Converting process modes to use comint mode
diff --git a/lisp/cus-start.el b/lisp/cus-start.el
index 0293d34d1cd..27fdb723441 100644
--- a/lisp/cus-start.el
+++ b/lisp/cus-start.el
@@ -880,7 +880,7 @@ since it could result in memory overflow and make Emacs crash."
       ;; Don't re-add to custom-delayed-init-variables post-startup.
       (unless after-init-time
         ;; Note this is the _only_ initialize property we handle.
-        (if (eq (cadr (memq :initialize rest)) 'custom-initialize-delay)
+        (if (eq (cadr (memq :initialize rest)) #'custom-initialize-delay)
             ;; These vars are defined early and should hence be initialized
             ;; early, even if this file happens to be loaded late.  so add them
             ;; to the end of custom-delayed-init-variables.  Otherwise,
diff --git a/lisp/custom.el b/lisp/custom.el
index 58ecd0439ad..5e354c4c595 100644
--- a/lisp/custom.el
+++ b/lisp/custom.el
@@ -125,17 +125,7 @@ This is used in files that are preloaded (or for autoloaded
 variables), so that the initialization is done in the run-time
 context rather than the build-time context.  This also has the
 side-effect that the (delayed) initialization is performed with
-the :set function.
-
-For variables in preloaded files, you can simply use this
-function for the :initialize property.  For autoloaded variables,
-you will also need to add an autoload stanza calling this
-function, and another one setting the standard-value property.
-Or you can wrap the defcustom in a progn, to force the autoloader
-to include all of it."             ; see eg vc-sccs-search-project-dir
-  ;; No longer true:
-  ;; "See `send-mail-function' in sendmail.el for an example."
-
+the :set function."
   ;; Defvar it so as to mark it special, etc (bug#25770).
   (internal--define-uninitialized-variable symbol)
 
diff --git a/lisp/dired-aux.el b/lisp/dired-aux.el
index 5a96742fda9..c765e4be45d 100644
--- a/lisp/dired-aux.el
+++ b/lisp/dired-aux.el
@@ -1168,7 +1168,10 @@ ARGS are command switches passed to PROGRAM.")
     ("\\.tar\\.bz2\\'" . "tar -cf - %i | bzip2 -c9 > %o")
     ("\\.tar\\.xz\\'" . "tar -cf - %i | xz -c9 > %o")
     ("\\.tar\\.zst\\'" . "tar -cf - %i | zstd -19 -o %o")
-    ("\\.zip\\'" . "zip %o -r --filesync %i"))
+    ("\\.tar\\.lz\\'" . "tar -cf - %i | lzip -c9 > %o")
+    ("\\.tar\\.lzo\\'" . "tar -cf - %i | lzop -c9 > %o")
+    ("\\.zip\\'" . "zip %o -r --filesync %i")
+    ("\\.pax\\'" . "pax -wf %o %i"))
   "Control the compression shell command for `dired-do-compress-to'.
 
 Each element is (REGEXP . CMD), where REGEXP is the name of the
diff --git a/lisp/dired-x.el b/lisp/dired-x.el
index aebffe339eb..5a52eccbbe3 100644
--- a/lisp/dired-x.el
+++ b/lisp/dired-x.el
@@ -1483,7 +1483,7 @@ a prefix argument, when it offers the filename near point as a default."
 ;;; Internal functions.
 
 ;; Fixme: This should probably use `thing-at-point'.  -- fx
-(define-obsolete-function-alias 'dired-file-name-at-point
+(define-obsolete-function-alias 'dired-filename-at-point
   #'dired-x-guess-file-name-at-point "28.1")
 (defun dired-x-guess-file-name-at-point ()
   "Return the filename closest to point, expanded.
diff --git a/lisp/emacs-lisp/byte-opt.el b/lisp/emacs-lisp/byte-opt.el
index cf89456541e..66a117fccc8 100644
--- a/lisp/emacs-lisp/byte-opt.el
+++ b/lisp/emacs-lisp/byte-opt.el
@@ -284,8 +284,10 @@
                           ;; If `fn' is from the same file, it has already
                           ;; been preprocessed!
                           `(function ,fn)
-                        (byte-compile-preprocess
-                         (byte-compile--reify-function fn)))))
+                        ;; Try and process it "in its original environment".
+                        (let ((byte-compile-bound-variables nil))
+                          (byte-compile-preprocess
+                           (byte-compile--reify-function fn))))))
            (if (eq (car-safe newfn) 'function)
                (byte-compile-unfold-lambda `(,(cadr newfn) ,@(cdr form)))
              ;; This can happen because of macroexp-warn-and-return &co.
@@ -374,185 +376,184 @@
   ;; the important aspect is that they are subrs that don't evaluate all of
   ;; their args.)
   ;;
-  (let ((fn (car-safe form))
-        tmp)
-    (cond ((not (consp form))
-           (if (not (and for-effect
-                         (or byte-compile-delete-errors
-                             (not (symbolp form))
-                             (eq form t))))
-             form))
-          ((eq fn 'quote)
-           (if (cdr (cdr form))
-               (byte-compile-warn "malformed quote form: `%s'"
-                                  (prin1-to-string form)))
-           ;; map (quote nil) to nil to simplify optimizer logic.
-           ;; map quoted constants to nil if for-effect (just because).
-           (and (nth 1 form)
-                (not for-effect)
-                form))
-          ((memq fn '(let let*))
-           ;; recursively enter the optimizer for the bindings and body
-           ;; of a let or let*.  This for depth-firstness: forms that
-           ;; are more deeply nested are optimized first.
-           (cons fn
+  ;; FIXME: There are a bunch of `byte-compile-warn' here which arguably
+  ;; have no place in an optimizer: the corresponding tests should be
+  ;; performed in `macroexpand-all', or in `cconv', or in `bytecomp'.
+  (let ((fn (car-safe form)))
+    (pcase form
+      ((pred (not consp))
+       (if (not (and for-effect
+                     (or byte-compile-delete-errors
+                         (not (symbolp form))
+                         (eq form t))))
+           form))
+      (`(quote . ,v)
+       (if (cdr v)
+           (byte-compile-warn "malformed quote form: `%s'"
+                              (prin1-to-string form)))
+       ;; Map (quote nil) to nil to simplify optimizer logic.
+       ;; Map quoted constants to nil if for-effect (just because).
+       (and (car v)
+            (not for-effect)
+            form))
+      (`(,(or 'let 'let*) . ,(or `(,bindings . ,exps) pcase--dontcare))
+       ;; Recursively enter the optimizer for the bindings and body
+       ;; of a let or let*.  This for depth-firstness: forms that
+       ;; are more deeply nested are optimized first.
+       (cons fn
              (cons
               (mapcar (lambda (binding)
-                         (if (symbolp binding)
-                             binding
-                           (if (cdr (cdr binding))
-                               (byte-compile-warn "malformed let binding: `%s'"
-                                                  (prin1-to-string binding)))
-                           (list (car binding)
-                                 (byte-optimize-form (nth 1 binding) nil))))
-                      (nth 1 form))
-              (byte-optimize-body (cdr (cdr form)) for-effect))))
-          ((eq fn 'cond)
-           (cons fn
-                 (mapcar (lambda (clause)
-                            (if (consp clause)
-                                (cons
-                                 (byte-optimize-form (car clause) nil)
-                                 (byte-optimize-body (cdr clause) for-effect))
-                              (byte-compile-warn "malformed cond form: `%s'"
-                                                 (prin1-to-string clause))
-                              clause))
-                         (cdr form))))
-          ((eq fn 'progn)
-           ;; As an extra added bonus, this simplifies (progn <x>) --> <x>.
-           (if (cdr (cdr form))
-               (macroexp-progn (byte-optimize-body (cdr form) for-effect))
-             (byte-optimize-form (nth 1 form) for-effect)))
-          ((eq fn 'prog1)
-           (if (cdr (cdr form))
-               (cons 'prog1
-                     (cons (byte-optimize-form (nth 1 form) for-effect)
-                           (byte-optimize-body (cdr (cdr form)) t)))
-             (byte-optimize-form (nth 1 form) for-effect)))
-
-          ((memq fn '(save-excursion save-restriction save-current-buffer))
-           ;; those subrs which have an implicit progn; it's not quite good
-           ;; enough to treat these like normal function calls.
-           ;; This can turn (save-excursion ...) into (save-excursion) which
-           ;; will be optimized away in the lap-optimize pass.
-           (cons fn (byte-optimize-body (cdr form) for-effect)))
-
-          ((eq fn 'if)
-           (when (< (length form) 3)
-             (byte-compile-warn "too few arguments for `if'"))
-           (cons fn
-             (cons (byte-optimize-form (nth 1 form) nil)
-               (cons
-                (byte-optimize-form (nth 2 form) for-effect)
-                (byte-optimize-body (nthcdr 3 form) for-effect)))))
-
-          ((memq fn '(and or))  ; Remember, and/or are control structures.
-           ;; Take forms off the back until we can't any more.
-           ;; In the future it could conceivably be a problem that the
-           ;; subexpressions of these forms are optimized in the reverse
-           ;; order, but it's ok for now.
-           (if for-effect
-               (let ((backwards (reverse (cdr form))))
-                 (while (and backwards
-                             (null (setcar backwards
-                                           (byte-optimize-form (car backwards)
-                                                               for-effect))))
-                   (setq backwards (cdr backwards)))
-                 (if (and (cdr form) (null backwards))
-                     (byte-compile-log
-                      "  all subforms of %s called for effect; deleted" form))
-                 (and backwards
-                      (cons fn (nreverse (mapcar 'byte-optimize-form
-                                                 backwards)))))
-             (cons fn (mapcar 'byte-optimize-form (cdr form)))))
-
-          ((eq fn 'while)
-           (unless (consp (cdr form))
-             (byte-compile-warn "too few arguments for `while'"))
-           (cons fn
-                 (cons (byte-optimize-form (cadr form) nil)
-                       (byte-optimize-body (cddr form) t))))
-
-          ((eq fn 'interactive)
-           (byte-compile-warn "misplaced interactive spec: `%s'"
-                              (prin1-to-string form))
-           nil)
-
-          ((eq fn 'function)
-           ;; This forms is compiled as constant or by breaking out
-           ;; all the subexpressions and compiling them separately.
-           form)
-
-          ((eq fn 'condition-case)
-           `(condition-case ,(nth 1 form) ;Not evaluated.
-                ,(byte-optimize-form (nth 2 form) for-effect)
-              ,@(mapcar (lambda (clause)
-                          `(,(car clause)
-                            ,@(byte-optimize-body (cdr clause) for-effect)))
-                        (nthcdr 3 form))))
-
-          ((eq fn 'unwind-protect)
-           ;; the "protected" part of an unwind-protect is compiled (and thus
-           ;; optimized) as a top-level form, so don't do it here.  But the
-           ;; non-protected part has the same for-effect status as the
-           ;; unwind-protect itself.  (The protected part is always for effect,
-           ;; but that isn't handled properly yet.)
-           (cons fn
-                 (cons (byte-optimize-form (nth 1 form) for-effect)
-                       (cdr (cdr form)))))
-
-          ((eq fn 'catch)
-           (cons fn
-                 (cons (byte-optimize-form (nth 1 form) nil)
-                       (byte-optimize-body (cdr form) for-effect))))
-
-          ((eq fn 'ignore)
-           ;; Don't treat the args to `ignore' as being
-           ;; computed for effect.  We want to avoid the warnings
-           ;; that might occur if they were treated that way.
-           ;; However, don't actually bother calling `ignore'.
-           `(prog1 nil . ,(mapcar 'byte-optimize-form (cdr form))))
-
-          ;; Needed as long as we run byte-optimize-form after cconv.
-          ((eq fn 'internal-make-closure) form)
-
-          ((eq (car-safe fn) 'lambda)
-           (let ((newform (byte-compile-unfold-lambda form)))
-             (if (eq newform form)
-                 ;; Some error occurred, avoid infinite recursion
-                 form
-               (byte-optimize-form newform for-effect))))
-
-          ((eq (car-safe fn) 'closure) form)
-
-          ((byte-code-function-p fn)
-           (cons fn (mapcar #'byte-optimize-form (cdr form))))
-
-          ((not (symbolp fn))
-           (byte-compile-warn "`%s' is a malformed function"
-                              (prin1-to-string fn))
-           form)
-
-          ((and for-effect (setq tmp (get fn 'side-effect-free))
-                (or byte-compile-delete-errors
-                    (eq tmp 'error-free)
-                    (progn
-                      (byte-compile-warn "value returned from %s is unused"
-                                         (prin1-to-string form))
-                      nil)))
-           (byte-compile-log "  %s called for effect; deleted" fn)
-           ;; appending a nil here might not be necessary, but it can't hurt.
-           (byte-optimize-form
-            (cons 'progn (append (cdr form) '(nil))) t))
+                        (if (symbolp binding)
+                            binding
+                          (if (cdr (cdr binding))
+                              (byte-compile-warn "malformed let binding: `%s'"
+                                                 (prin1-to-string binding)))
+                          (list (car binding)
+                                (byte-optimize-form (nth 1 binding) nil))))
+                      bindings)
+              (byte-optimize-body exps for-effect))))
+      (`(cond . ,clauses)
+       (cons fn
+             (mapcar (lambda (clause)
+                       (if (consp clause)
+                           (cons
+                            (byte-optimize-form (car clause) nil)
+                            (byte-optimize-body (cdr clause) for-effect))
+                         (byte-compile-warn "malformed cond form: `%s'"
+                                            (prin1-to-string clause))
+                         clause))
+                     clauses)))
+      (`(progn . ,exps)
+       ;; As an extra added bonus, this simplifies (progn <x>) --> <x>.
+       (if (cdr exps)
+           (macroexp-progn (byte-optimize-body exps for-effect))
+         (byte-optimize-form (car exps) for-effect)))
+      (`(prog1 . ,(or `(,exp . ,exps) pcase--dontcare))
+       (if exps
+           `(prog1 ,(byte-optimize-form exp for-effect)
+              . ,(byte-optimize-body exps t))
+         (byte-optimize-form exp for-effect)))
+
+      (`(,(or `save-excursion `save-restriction `save-current-buffer) . ,exps)
+       ;; Those subrs which have an implicit progn; it's not quite good
+       ;; enough to treat these like normal function calls.
+       ;; This can turn (save-excursion ...) into (save-excursion) which
+       ;; will be optimized away in the lap-optimize pass.
+       (cons fn (byte-optimize-body exps for-effect)))
+
+      (`(if ,test ,then . ,else)
+       `(if ,(byte-optimize-form test nil)
+            ,(byte-optimize-form then for-effect)
+          . ,(byte-optimize-body else for-effect)))
+      (`(if . ,_)
+       (byte-compile-warn "too few arguments for `if'"))
+
+      (`(,(or 'and 'or) . ,exps) ; Remember, and/or are control structures.
+       ;; Take forms off the back until we can't any more.
+       ;; In the future it could conceivably be a problem that the
+       ;; subexpressions of these forms are optimized in the reverse
+       ;; order, but it's ok for now.
+       (if for-effect
+           (let ((backwards (reverse exps)))
+             (while (and backwards
+                         (null (setcar backwards
+                                       (byte-optimize-form (car backwards)
+                                                           for-effect))))
+               (setq backwards (cdr backwards)))
+             (if (and exps (null backwards))
+                 (byte-compile-log
+                  "  all subforms of %s called for effect; deleted" form))
+             (and backwards
+                  (cons fn (nreverse (mapcar #'byte-optimize-form
+                                             backwards)))))
+         (cons fn (mapcar #'byte-optimize-form exps))))
+
+      (`(while ,exp . ,exps)
+       `(while ,(byte-optimize-form exp nil)
+          . ,(byte-optimize-body exps t)))
+      (`(while . ,_)
+       (byte-compile-warn "too few arguments for `while'"))
+
+      (`(interactive . ,_)
+       (byte-compile-warn "misplaced interactive spec: `%s'"
+                          (prin1-to-string form))
+       nil)
+
+      (`(function . ,_)
+       ;; This forms is compiled as constant or by breaking out
+       ;; all the subexpressions and compiling them separately.
+       form)
 
-          (t
-           ;; Otherwise, no args can be considered to be for-effect,
-           ;; even if the called function is for-effect, because we
-           ;; don't know anything about that function.
-           (let ((form (cons fn (mapcar #'byte-optimize-form (cdr form)))))
-             (if (get fn 'pure)
-                 (byte-optimize-constant-args form)
-               form))))))
+      (`(condition-case . ,(or `(,var ,exp . ,clauses) pcase--dontcare))
+       `(condition-case ,var            ;Not evaluated.
+            ,(byte-optimize-form exp for-effect)
+          ,@(mapcar (lambda (clause)
+                      `(,(car clause)
+                        ,@(byte-optimize-body (cdr clause) for-effect)))
+                    clauses)))
+
+      (`(unwind-protect . ,(or `(,exp . ,exps) pcase--dontcare))
+       ;; The "protected" part of an unwind-protect is compiled (and thus
+       ;; optimized) as a top-level form, so don't do it here.  But the
+       ;; non-protected part has the same for-effect status as the
+       ;; unwind-protect itself.  (The protected part is always for effect,
+       ;; but that isn't handled properly yet.)
+       `(unwind-protect ,(byte-optimize-form exp for-effect) . ,exps))
+
+      (`(catch . ,(or `(,tag . ,exps) pcase--dontcare))
+       `(catch ,(byte-optimize-form tag nil)
+          . ,(byte-optimize-body exps for-effect)))
+
+      (`(ignore . ,exps)
+       ;; Don't treat the args to `ignore' as being
+       ;; computed for effect.  We want to avoid the warnings
+       ;; that might occur if they were treated that way.
+       ;; However, don't actually bother calling `ignore'.
+       `(prog1 nil . ,(mapcar #'byte-optimize-form exps)))
+
+      ;; Needed as long as we run byte-optimize-form after cconv.
+      (`(internal-make-closure . ,_) form)
+
+      (`((lambda . ,_) . ,_)
+       (let ((newform (byte-compile-unfold-lambda form)))
+         (if (eq newform form)
+             ;; Some error occurred, avoid infinite recursion.
+             form
+           (byte-optimize-form newform for-effect))))
+
+      ;; FIXME: Strictly speaking, I think this is a bug: (closure...)
+      ;; is a *value* and shouldn't appear in the car.
+      (`((closure . ,_) . ,_) form)
+
+      (`(,(pred byte-code-function-p) . ,exps)
+       (cons fn (mapcar #'byte-optimize-form exps)))
+
+      (`(,(pred (not symbolp)) . ,_)
+       (byte-compile-warn "`%s' is a malformed function"
+                          (prin1-to-string fn))
+       form)
+
+      ((guard (when for-effect
+                (if-let ((tmp (get fn 'side-effect-free)))
+                    (or byte-compile-delete-errors
+                        (eq tmp 'error-free)
+                        (progn
+                          (byte-compile-warn "value returned from %s is unused"
+                                             (prin1-to-string form))
+                          nil)))))
+       (byte-compile-log "  %s called for effect; deleted" fn)
+       ;; appending a nil here might not be necessary, but it can't hurt.
+       (byte-optimize-form
+        (cons 'progn (append (cdr form) '(nil))) t))
+
+      (_
+       ;; Otherwise, no args can be considered to be for-effect,
+       ;; even if the called function is for-effect, because we
+       ;; don't know anything about that function.
+       (let ((form (cons fn (mapcar #'byte-optimize-form (cdr form)))))
+         (if (get fn 'pure)
+             (byte-optimize-constant-args form)
+           form))))))
 
 (defun byte-optimize-form (form &optional for-effect)
   "The source-level pass of the optimizer."
@@ -1562,467 +1563,548 @@ If FOR-EFFECT is non-nil, the return value is assumed to be of no importance."
         ;; You may notice that sequences like "dup varset discard" are
         ;; optimized but sequences like "dup varset TAG1: discard" are not.
         ;; You may be tempted to change this; resist that temptation.
-        (cond ;;
-              ;; <side-effect-free> pop -->  <deleted>
-              ;;  ...including:
-              ;; const-X pop   -->  <deleted>
-              ;; varref-X pop  -->  <deleted>
-              ;; dup pop       -->  <deleted>
-              ;;
-              ((and (eq 'byte-discard (car lap1))
-                    (memq (car lap0) side-effect-free))
-               (setq keep-going t)
-               (setq tmp (aref byte-stack+-info (symbol-value (car lap0))))
-               (setq rest (cdr rest))
-               (cond ((= tmp 1)
-                      (byte-compile-log-lap
-                       "  %s discard\t-->\t<deleted>" lap0)
-                      (setq lap (delq lap0 (delq lap1 lap))))
-                     ((= tmp 0)
-                      (byte-compile-log-lap
-                       "  %s discard\t-->\t<deleted> discard" lap0)
-                      (setq lap (delq lap0 lap)))
-                     ((= tmp -1)
-                      (byte-compile-log-lap
-                       "  %s discard\t-->\tdiscard discard" lap0)
-                      (setcar lap0 'byte-discard)
-                      (setcdr lap0 0))
-                     ((error "Optimizer error: too much on the stack"))))
-              ;;
-              ;; goto*-X X:  -->  X:
-              ;;
-              ((and (memq (car lap0) byte-goto-ops)
-                    (eq (cdr lap0) lap1))
-               (cond ((eq (car lap0) 'byte-goto)
-                      (setq lap (delq lap0 lap))
-                      (setq tmp "<deleted>"))
-                     ((memq (car lap0) byte-goto-always-pop-ops)
-                      (setcar lap0 (setq tmp 'byte-discard))
-                      (setcdr lap0 0))
-                     ((error "Depth conflict at tag %d" (nth 2 lap0))))
-               (and (memq byte-optimize-log '(t byte))
-                    (byte-compile-log "  (goto %s) %s:\t-->\t%s %s:"
-                                      (nth 1 lap1) (nth 1 lap1)
-                                      tmp (nth 1 lap1)))
-               (setq keep-going t))
-              ;;
-              ;; varset-X varref-X  -->  dup varset-X
-              ;; varbind-X varref-X  -->  dup varbind-X
-              ;; const/dup varset-X varref-X --> const/dup varset-X const/dup
-              ;; const/dup varbind-X varref-X --> const/dup varbind-X const/dup
-              ;; The latter two can enable other optimizations.
-              ;;
-              ;; For lexical variables, we could do the same
-              ;;   stack-set-X+1 stack-ref-X  -->  dup stack-set-X+2
-              ;; but this is a very minor gain, since dup is stack-ref-0,
-              ;; i.e. it's only better if X>5, and even then it comes
-              ;; at the cost of an extra stack slot.  Let's not bother.
-              ((and (eq 'byte-varref (car lap2))
-                    (eq (cdr lap1) (cdr lap2))
-                    (memq (car lap1) '(byte-varset byte-varbind)))
-               (if (and (setq tmp (memq (car (cdr lap2)) byte-boolean-vars))
-                        (not (eq (car lap0) 'byte-constant)))
-                   nil
-                 (setq keep-going t)
-                 (if (memq (car lap0) '(byte-constant byte-dup))
-                     (progn
-                       (setq tmp (if (or (not tmp)
-                                         (macroexp--const-symbol-p
-                                          (car (cdr lap0))))
-                                     (cdr lap0)
-                                   (byte-compile-get-constant t)))
-                       (byte-compile-log-lap "  %s %s %s\t-->\t%s %s %s"
-                                             lap0 lap1 lap2 lap0 lap1
-                                             (cons (car lap0) tmp))
-                       (setcar lap2 (car lap0))
-                       (setcdr lap2 tmp))
-                   (byte-compile-log-lap "  %s %s\t-->\tdup %s" lap1 lap2 lap1)
-                   (setcar lap2 (car lap1))
-                   (setcar lap1 'byte-dup)
-                   (setcdr lap1 0)
-                   ;; The stack depth gets locally increased, so we will
-                   ;; increase maxdepth in case depth = maxdepth here.
-                   ;; This can cause the third argument to byte-code to
-                   ;; be larger than necessary.
-                   (setq add-depth 1))))
-              ;;
-              ;; dup varset-X discard  -->  varset-X
-              ;; dup varbind-X discard  -->  varbind-X
-              ;; dup stack-set-X discard  -->  stack-set-X-1
-              ;; (the varbind variant can emerge from other optimizations)
-              ;;
-              ((and (eq 'byte-dup (car lap0))
-                    (eq 'byte-discard (car lap2))
-                    (memq (car lap1) '(byte-varset byte-varbind
-                                       byte-stack-set)))
-               (byte-compile-log-lap "  dup %s discard\t-->\t%s" lap1 lap1)
-               (setq keep-going t
-                     rest (cdr rest))
-               (if (eq 'byte-stack-set (car lap1)) (cl-decf (cdr lap1)))
-               (setq lap (delq lap0 (delq lap2 lap))))
-              ;;
-              ;; not goto-X-if-nil              -->  goto-X-if-non-nil
-              ;; not goto-X-if-non-nil          -->  goto-X-if-nil
-              ;;
-              ;; it is wrong to do the same thing for the -else-pop variants.
-              ;;
-              ((and (eq 'byte-not (car lap0))
-                    (memq (car lap1) '(byte-goto-if-nil byte-goto-if-not-nil)))
-               (byte-compile-log-lap "  not %s\t-->\t%s"
-                                     lap1
-                                     (cons
-                                      (if (eq (car lap1) 'byte-goto-if-nil)
-                                          'byte-goto-if-not-nil
-                                        'byte-goto-if-nil)
-                                      (cdr lap1)))
-               (setcar lap1 (if (eq (car lap1) 'byte-goto-if-nil)
-                                'byte-goto-if-not-nil
-                                'byte-goto-if-nil))
-               (setq lap (delq lap0 lap))
-               (setq keep-going t))
-              ;;
-              ;; goto-X-if-nil     goto-Y X:  -->  goto-Y-if-non-nil X:
-              ;; goto-X-if-non-nil goto-Y X:  -->  goto-Y-if-nil     X:
-              ;;
-              ;; it is wrong to do the same thing for the -else-pop variants.
-              ;;
-              ((and (memq (car lap0)
-                          '(byte-goto-if-nil byte-goto-if-not-nil))     ; gotoX
-                    (eq 'byte-goto (car lap1))                  ; gotoY
-                    (eq (cdr lap0) lap2))                       ; TAG X
-               (let ((inverse (if (eq 'byte-goto-if-nil (car lap0))
-                                  'byte-goto-if-not-nil 'byte-goto-if-nil)))
-                 (byte-compile-log-lap "  %s %s %s:\t-->\t%s %s:"
-                                       lap0 lap1 lap2
-                                       (cons inverse (cdr lap1)) lap2)
-                 (setq lap (delq lap0 lap))
-                 (setcar lap1 inverse)
-                 (setq keep-going t)))
-              ;;
-              ;; const goto-if-* --> whatever
-              ;;
-              ((and (eq 'byte-constant (car lap0))
-                    (memq (car lap1) byte-conditional-ops)
-                    ;; If the `byte-constant's cdr is not a cons cell, it has
-                    ;; to be an index into the constant pool); even though
-                    ;; it'll be a constant, that constant is not known yet
-                    ;; (it's typically a free variable of a closure, so will
-                    ;; only be known when the closure will be built at
-                    ;; run-time).
-                    (consp (cdr lap0)))
-               (cond ((if (memq (car lap1) '(byte-goto-if-nil
-                                             byte-goto-if-nil-else-pop))
-                          (car (cdr lap0))
-                        (not (car (cdr lap0))))
-                      (byte-compile-log-lap "  %s %s\t-->\t<deleted>"
-                                            lap0 lap1)
-                      (setq rest (cdr rest)
-                            lap (delq lap0 (delq lap1 lap))))
-                     (t
-                      (byte-compile-log-lap "  %s %s\t-->\t%s"
-                                            lap0 lap1
-                                            (cons 'byte-goto (cdr lap1)))
-                      (when (memq (car lap1) byte-goto-always-pop-ops)
-                        (setq lap (delq lap0 lap)))
-                      (setcar lap1 'byte-goto)))
-               (setq keep-going t))
-              ;;
-              ;; varref-X varref-X  -->  varref-X dup
-              ;; varref-X [dup ...] varref-X  -->  varref-X [dup ...] dup
-              ;; stackref-X [dup ...] stackref-X+N --> stackref-X [dup ...] dup
-              ;; We don't optimize the const-X variations on this here,
-              ;; because that would inhibit some goto optimizations; we
-              ;; optimize the const-X case after all other optimizations.
-              ;;
-              ((and (memq (car lap0) '(byte-varref byte-stack-ref))
-                    (progn
-                      (setq tmp (cdr rest))
-                      (setq tmp2 0)
-                      (while (eq (car (car tmp)) 'byte-dup)
-                        (setq tmp2 (1+ tmp2))
-                        (setq tmp (cdr tmp)))
-                      t)
-                    (eq (if (eq 'byte-stack-ref (car lap0))
-                            (+ tmp2 1 (cdr lap0))
-                          (cdr lap0))
-                        (cdr (car tmp)))
-                    (eq (car lap0) (car (car tmp))))
-               (if (memq byte-optimize-log '(t byte))
-                   (let ((str ""))
-                     (setq tmp2 (cdr rest))
-                     (while (not (eq tmp tmp2))
-                       (setq tmp2 (cdr tmp2)
-                             str (concat str " dup")))
-                     (byte-compile-log-lap "  %s%s %s\t-->\t%s%s dup"
-                                           lap0 str lap0 lap0 str)))
-               (setq keep-going t)
-               (setcar (car tmp) 'byte-dup)
-               (setcdr (car tmp) 0)
-               (setq rest tmp))
-              ;;
-              ;; TAG1: TAG2: --> TAG1: <deleted>
-              ;; (and other references to TAG2 are replaced with TAG1)
-              ;;
-              ((and (eq (car lap0) 'TAG)
-                    (eq (car lap1) 'TAG))
-               (and (memq byte-optimize-log '(t byte))
-                    (byte-compile-log "  adjacent tags %d and %d merged"
-                                      (nth 1 lap1) (nth 1 lap0)))
-               (setq tmp3 lap)
-               (while (setq tmp2 (rassq lap0 tmp3))
-                 (setcdr tmp2 lap1)
-                 (setq tmp3 (cdr (memq tmp2 tmp3))))
-               (setq lap (delq lap0 lap)
-                     keep-going t)
-               ;; replace references to tag in jump tables, if any
-               (dolist (table byte-compile-jump-tables)
-                   (maphash #'(lambda (value tag)
-                                (when (equal tag lap0)
-                                  (puthash value lap1 table)))
-                            table)))
-              ;;
-              ;; unused-TAG: --> <deleted>
-              ;;
-              ((and (eq 'TAG (car lap0))
-                    (not (rassq lap0 lap))
-                    ;; make sure this tag isn't used in a jump-table
-                    (cl-loop for table in byte-compile-jump-tables
-                             when (member lap0 (hash-table-values table))
-                             return nil finally return t))
-               (and (memq byte-optimize-log '(t byte))
-                    (byte-compile-log "  unused tag %d removed" (nth 1 lap0)))
-               (setq lap (delq lap0 lap)
-                     keep-going t))
-              ;;
-              ;; goto   ... --> goto   <delete until TAG or end>
-              ;; return ... --> return <delete until TAG or end>
-              ;; (unless a jump-table is being used, where deleting may affect
-              ;; other valid case bodies)
-              ;;
-              ((and (memq (car lap0) '(byte-goto byte-return))
-                    (not (memq (car lap1) '(TAG nil)))
-                    ;; FIXME: Instead of deferring simply when jump-tables are
-                    ;; being used, keep a list of tags used for switch tags and
-                    ;; use them instead (see `byte-compile-inline-lapcode').
-                    (not byte-compile-jump-tables))
-               (setq tmp rest)
-               (let ((i 0)
-                     (opt-p (memq byte-optimize-log '(t lap)))
-                     str deleted)
-                 (while (and (setq tmp (cdr tmp))
-                             (not (eq 'TAG (car (car tmp)))))
-                   (if opt-p (setq deleted (cons (car tmp) deleted)
-                                   str (concat str " %s")
-                                   i (1+ i))))
-                 (if opt-p
-                     (let ((tagstr
-                            (if (eq 'TAG (car (car tmp)))
-                                (format "%d:" (car (cdr (car tmp))))
-                              (or (car tmp) ""))))
-                       (if (< i 6)
-                           (apply 'byte-compile-log-lap-1
-                                  (concat "  %s" str
-                                          " %s\t-->\t%s <deleted> %s")
-                                  lap0
-                                  (nconc (nreverse deleted)
-                                         (list tagstr lap0 tagstr)))
-                         (byte-compile-log-lap
-                          "  %s <%d unreachable op%s> %s\t-->\t%s <deleted> %s"
-                          lap0 i (if (= i 1) "" "s")
-                          tagstr lap0 tagstr))))
-                 (rplacd rest tmp))
-               (setq keep-going t))
-              ;;
-              ;; <safe-op> unbind --> unbind <safe-op>
-              ;; (this may enable other optimizations.)
-              ;;
-              ((and (eq 'byte-unbind (car lap1))
-                    (memq (car lap0) byte-after-unbind-ops))
-               (byte-compile-log-lap "  %s %s\t-->\t%s %s" lap0 lap1 lap1 lap0)
-               (setcar rest lap1)
-               (setcar (cdr rest) lap0)
-               (setq keep-going t))
-              ;;
-              ;; varbind-X unbind-N         -->  discard unbind-(N-1)
-              ;; save-excursion unbind-N    -->  unbind-(N-1)
-              ;; save-restriction unbind-N  -->  unbind-(N-1)
-              ;;
-              ((and (eq 'byte-unbind (car lap1))
-                    (memq (car lap0) '(byte-varbind byte-save-excursion
-                                       byte-save-restriction))
-                    (< 0 (cdr lap1)))
-               (if (zerop (setcdr lap1 (1- (cdr lap1))))
-                   (delq lap1 rest))
-               (if (eq (car lap0) 'byte-varbind)
-                   (setcar rest (cons 'byte-discard 0))
+        (cond
+         ;; <side-effect-free> pop -->  <deleted>
+         ;;  ...including:
+         ;; const-X pop   -->  <deleted>
+         ;; varref-X pop  -->  <deleted>
+         ;; dup pop       -->  <deleted>
+         ;;
+         ((and (eq 'byte-discard (car lap1))
+               (memq (car lap0) side-effect-free))
+          (setq keep-going t)
+          (setq tmp (aref byte-stack+-info (symbol-value (car lap0))))
+          (setq rest (cdr rest))
+          (cond ((= tmp 1)
+                 (byte-compile-log-lap
+                  "  %s discard\t-->\t<deleted>" lap0)
+                 (setq lap (delq lap0 (delq lap1 lap))))
+                ((= tmp 0)
+                 (byte-compile-log-lap
+                  "  %s discard\t-->\t<deleted> discard" lap0)
                  (setq lap (delq lap0 lap)))
-               (byte-compile-log-lap "  %s %s\t-->\t%s %s"
-                 lap0 (cons (car lap1) (1+ (cdr lap1)))
-                 (if (eq (car lap0) 'byte-varbind)
-                     (car rest)
-                   (car (cdr rest)))
-                 (if (and (/= 0 (cdr lap1))
-                          (eq (car lap0) 'byte-varbind))
-                     (car (cdr rest))
-                   ""))
-               (setq keep-going t))
-              ;;
-              ;; goto*-X ... X: goto-Y  --> goto*-Y
-              ;; goto-X ...  X: return  --> return
-              ;;
-              ((and (memq (car lap0) byte-goto-ops)
-                    (memq (car (setq tmp (nth 1 (memq (cdr lap0) lap))))
-                          '(byte-goto byte-return)))
-               (cond ((and (not (eq tmp lap0))
-                           (or (eq (car lap0) 'byte-goto)
-                               (eq (car tmp) 'byte-goto)))
-                      (byte-compile-log-lap "  %s [%s]\t-->\t%s"
-                                            (car lap0) tmp tmp)
-                      (if (eq (car tmp) 'byte-return)
-                          (setcar lap0 'byte-return))
-                      (setcdr lap0 (cdr tmp))
-                      (setq keep-going t))))
-              ;;
-              ;; goto-*-else-pop X ... X: goto-if-* --> whatever
-              ;; goto-*-else-pop X ... X: discard --> whatever
-              ;;
-              ((and (memq (car lap0) '(byte-goto-if-nil-else-pop
-                                       byte-goto-if-not-nil-else-pop))
-                    (memq (car (car (setq tmp (cdr (memq (cdr lap0) lap)))))
-                          (eval-when-compile
-                           (cons 'byte-discard byte-conditional-ops)))
-                    (not (eq lap0 (car tmp))))
-               (setq tmp2 (car tmp))
-               (setq tmp3 (assq (car lap0) '((byte-goto-if-nil-else-pop
-                                              byte-goto-if-nil)
-                                             (byte-goto-if-not-nil-else-pop
-                                              byte-goto-if-not-nil))))
-               (if (memq (car tmp2) tmp3)
-                   (progn (setcar lap0 (car tmp2))
-                          (setcdr lap0 (cdr tmp2))
-                          (byte-compile-log-lap "  %s-else-pop [%s]\t-->\t%s"
-                                                (car lap0) tmp2 lap0))
-                 ;; Get rid of the -else-pop's and jump one step further.
+                ((= tmp -1)
+                 (byte-compile-log-lap
+                  "  %s discard\t-->\tdiscard discard" lap0)
+                 (setcar lap0 'byte-discard)
+                 (setcdr lap0 0))
+                ((error "Optimizer error: too much on the stack"))))
+         ;;
+         ;; goto*-X X:  -->  X:
+         ;;
+         ((and (memq (car lap0) byte-goto-ops)
+               (eq (cdr lap0) lap1))
+          (cond ((eq (car lap0) 'byte-goto)
+                 (setq lap (delq lap0 lap))
+                 (setq tmp "<deleted>"))
+                ((memq (car lap0) byte-goto-always-pop-ops)
+                 (setcar lap0 (setq tmp 'byte-discard))
+                 (setcdr lap0 0))
+                ((error "Depth conflict at tag %d" (nth 2 lap0))))
+          (and (memq byte-optimize-log '(t byte))
+               (byte-compile-log "  (goto %s) %s:\t-->\t%s %s:"
+                                 (nth 1 lap1) (nth 1 lap1)
+                                 tmp (nth 1 lap1)))
+          (setq keep-going t))
+         ;;
+         ;; varset-X varref-X  -->  dup varset-X
+         ;; varbind-X varref-X  -->  dup varbind-X
+         ;; const/dup varset-X varref-X --> const/dup varset-X const/dup
+         ;; const/dup varbind-X varref-X --> const/dup varbind-X const/dup
+         ;; The latter two can enable other optimizations.
+         ;;
+         ;; For lexical variables, we could do the same
+         ;;   stack-set-X+1 stack-ref-X  -->  dup stack-set-X+2
+         ;; but this is a very minor gain, since dup is stack-ref-0,
+         ;; i.e. it's only better if X>5, and even then it comes
+         ;; at the cost of an extra stack slot.  Let's not bother.
+         ((and (eq 'byte-varref (car lap2))
+               (eq (cdr lap1) (cdr lap2))
+               (memq (car lap1) '(byte-varset byte-varbind)))
+          (if (and (setq tmp (memq (car (cdr lap2)) byte-boolean-vars))
+                   (not (eq (car lap0) 'byte-constant)))
+              nil
+            (setq keep-going t)
+            (if (memq (car lap0) '(byte-constant byte-dup))
+                (progn
+                  (setq tmp (if (or (not tmp)
+                                    (macroexp--const-symbol-p
+                                     (car (cdr lap0))))
+                                (cdr lap0)
+                              (byte-compile-get-constant t)))
+                  (byte-compile-log-lap "  %s %s %s\t-->\t%s %s %s"
+                                        lap0 lap1 lap2 lap0 lap1
+                                        (cons (car lap0) tmp))
+                  (setcar lap2 (car lap0))
+                  (setcdr lap2 tmp))
+              (byte-compile-log-lap "  %s %s\t-->\tdup %s" lap1 lap2 lap1)
+              (setcar lap2 (car lap1))
+              (setcar lap1 'byte-dup)
+              (setcdr lap1 0)
+              ;; The stack depth gets locally increased, so we will
+              ;; increase maxdepth in case depth = maxdepth here.
+              ;; This can cause the third argument to byte-code to
+              ;; be larger than necessary.
+              (setq add-depth 1))))
+         ;;
+         ;; dup varset-X discard  -->  varset-X
+         ;; dup varbind-X discard  -->  varbind-X
+         ;; dup stack-set-X discard  -->  stack-set-X-1
+         ;; (the varbind variant can emerge from other optimizations)
+         ;;
+         ((and (eq 'byte-dup (car lap0))
+               (eq 'byte-discard (car lap2))
+               (memq (car lap1) '(byte-varset byte-varbind
+                                  byte-stack-set)))
+          (byte-compile-log-lap "  dup %s discard\t-->\t%s" lap1 lap1)
+          (setq keep-going t
+                rest (cdr rest))
+          (if (eq 'byte-stack-set (car lap1)) (cl-decf (cdr lap1)))
+          (setq lap (delq lap0 (delq lap2 lap))))
+         ;;
+         ;; not goto-X-if-nil              -->  goto-X-if-non-nil
+         ;; not goto-X-if-non-nil          -->  goto-X-if-nil
+         ;;
+         ;; it is wrong to do the same thing for the -else-pop variants.
+         ;;
+         ((and (eq 'byte-not (car lap0))
+               (memq (car lap1) '(byte-goto-if-nil byte-goto-if-not-nil)))
+          (byte-compile-log-lap "  not %s\t-->\t%s"
+                                lap1
+                                (cons
+                                 (if (eq (car lap1) 'byte-goto-if-nil)
+                                     'byte-goto-if-not-nil
+                                   'byte-goto-if-nil)
+                                 (cdr lap1)))
+          (setcar lap1 (if (eq (car lap1) 'byte-goto-if-nil)
+                           'byte-goto-if-not-nil
+                         'byte-goto-if-nil))
+          (setq lap (delq lap0 lap))
+          (setq keep-going t))
+         ;;
+         ;; goto-X-if-nil     goto-Y X:  -->  goto-Y-if-non-nil X:
+         ;; goto-X-if-non-nil goto-Y X:  -->  goto-Y-if-nil     X:
+         ;;
+         ;; it is wrong to do the same thing for the -else-pop variants.
+         ;;
+         ((and (memq (car lap0)
+                     '(byte-goto-if-nil byte-goto-if-not-nil)) ; gotoX
+               (eq 'byte-goto (car lap1))                      ; gotoY
+               (eq (cdr lap0) lap2))                           ; TAG X
+          (let ((inverse (if (eq 'byte-goto-if-nil (car lap0))
+                             'byte-goto-if-not-nil 'byte-goto-if-nil)))
+            (byte-compile-log-lap "  %s %s %s:\t-->\t%s %s:"
+                                  lap0 lap1 lap2
+                                  (cons inverse (cdr lap1)) lap2)
+            (setq lap (delq lap0 lap))
+            (setcar lap1 inverse)
+            (setq keep-going t)))
+         ;;
+         ;; const goto-if-* --> whatever
+         ;;
+         ((and (eq 'byte-constant (car lap0))
+               (memq (car lap1) byte-conditional-ops)
+               ;; If the `byte-constant's cdr is not a cons cell, it has
+               ;; to be an index into the constant pool); even though
+               ;; it'll be a constant, that constant is not known yet
+               ;; (it's typically a free variable of a closure, so will
+               ;; only be known when the closure will be built at
+               ;; run-time).
+               (consp (cdr lap0)))
+          (cond ((if (memq (car lap1) '(byte-goto-if-nil
+                                        byte-goto-if-nil-else-pop))
+                     (car (cdr lap0))
+                   (not (car (cdr lap0))))
+                 (byte-compile-log-lap "  %s %s\t-->\t<deleted>"
+                                       lap0 lap1)
+                 (setq rest (cdr rest)
+                       lap (delq lap0 (delq lap1 lap))))
+                (t
+                 (byte-compile-log-lap "  %s %s\t-->\t%s"
+                                       lap0 lap1
+                                       (cons 'byte-goto (cdr lap1)))
+                 (when (memq (car lap1) byte-goto-always-pop-ops)
+                   (setq lap (delq lap0 lap)))
+                 (setcar lap1 'byte-goto)))
+          (setq keep-going t))
+         ;;
+         ;; varref-X varref-X  -->  varref-X dup
+         ;; varref-X [dup ...] varref-X  -->  varref-X [dup ...] dup
+         ;; stackref-X [dup ...] stackref-X+N --> stackref-X [dup ...] dup
+         ;; We don't optimize the const-X variations on this here,
+         ;; because that would inhibit some goto optimizations; we
+         ;; optimize the const-X case after all other optimizations.
+         ;;
+         ((and (memq (car lap0) '(byte-varref byte-stack-ref))
+               (progn
+                 (setq tmp (cdr rest))
+                 (setq tmp2 0)
+                 (while (eq (car (car tmp)) 'byte-dup)
+                   (setq tmp2 (1+ tmp2))
+                   (setq tmp (cdr tmp)))
+                 t)
+               (eq (if (eq 'byte-stack-ref (car lap0))
+                       (+ tmp2 1 (cdr lap0))
+                     (cdr lap0))
+                   (cdr (car tmp)))
+               (eq (car lap0) (car (car tmp))))
+          (if (memq byte-optimize-log '(t byte))
+              (let ((str ""))
+                (setq tmp2 (cdr rest))
+                (while (not (eq tmp tmp2))
+                  (setq tmp2 (cdr tmp2)
+                        str (concat str " dup")))
+                (byte-compile-log-lap "  %s%s %s\t-->\t%s%s dup"
+                                      lap0 str lap0 lap0 str)))
+          (setq keep-going t)
+          (setcar (car tmp) 'byte-dup)
+          (setcdr (car tmp) 0)
+          (setq rest tmp))
+         ;;
+         ;; TAG1: TAG2: --> TAG1: <deleted>
+         ;; (and other references to TAG2 are replaced with TAG1)
+         ;;
+         ((and (eq (car lap0) 'TAG)
+               (eq (car lap1) 'TAG))
+          (and (memq byte-optimize-log '(t byte))
+               (byte-compile-log "  adjacent tags %d and %d merged"
+                                 (nth 1 lap1) (nth 1 lap0)))
+          (setq tmp3 lap)
+          (while (setq tmp2 (rassq lap0 tmp3))
+            (setcdr tmp2 lap1)
+            (setq tmp3 (cdr (memq tmp2 tmp3))))
+          (setq lap (delq lap0 lap)
+                keep-going t)
+          ;; replace references to tag in jump tables, if any
+          (dolist (table byte-compile-jump-tables)
+            (maphash #'(lambda (value tag)
+                         (when (equal tag lap0)
+                           (puthash value lap1 table)))
+                     table)))
+         ;;
+         ;; unused-TAG: --> <deleted>
+         ;;
+         ((and (eq 'TAG (car lap0))
+               (not (rassq lap0 lap))
+               ;; make sure this tag isn't used in a jump-table
+               (cl-loop for table in byte-compile-jump-tables
+                        when (member lap0 (hash-table-values table))
+                        return nil finally return t))
+          (and (memq byte-optimize-log '(t byte))
+               (byte-compile-log "  unused tag %d removed" (nth 1 lap0)))
+          (setq lap (delq lap0 lap)
+                keep-going t))
+         ;;
+         ;; goto   ... --> goto   <delete until TAG or end>
+         ;; return ... --> return <delete until TAG or end>
+         ;; (unless a jump-table is being used, where deleting may affect
+         ;; other valid case bodies)
+         ;;
+         ((and (memq (car lap0) '(byte-goto byte-return))
+               (not (memq (car lap1) '(TAG nil)))
+               ;; FIXME: Instead of deferring simply when jump-tables are
+               ;; being used, keep a list of tags used for switch tags and
+               ;; use them instead (see `byte-compile-inline-lapcode').
+               (not byte-compile-jump-tables))
+          (setq tmp rest)
+          (let ((i 0)
+                (opt-p (memq byte-optimize-log '(t lap)))
+                str deleted)
+            (while (and (setq tmp (cdr tmp))
+                        (not (eq 'TAG (car (car tmp)))))
+              (if opt-p (setq deleted (cons (car tmp) deleted)
+                              str (concat str " %s")
+                              i (1+ i))))
+            (if opt-p
+                (let ((tagstr
+                       (if (eq 'TAG (car (car tmp)))
+                           (format "%d:" (car (cdr (car tmp))))
+                         (or (car tmp) ""))))
+                  (if (< i 6)
+                      (apply 'byte-compile-log-lap-1
+                             (concat "  %s" str
+                                     " %s\t-->\t%s <deleted> %s")
+                             lap0
+                             (nconc (nreverse deleted)
+                                    (list tagstr lap0 tagstr)))
+                    (byte-compile-log-lap
+                     "  %s <%d unreachable op%s> %s\t-->\t%s <deleted> %s"
+                     lap0 i (if (= i 1) "" "s")
+                     tagstr lap0 tagstr))))
+            (rplacd rest tmp))
+          (setq keep-going t))
+         ;;
+         ;; <safe-op> unbind --> unbind <safe-op>
+         ;; (this may enable other optimizations.)
+         ;;
+         ((and (eq 'byte-unbind (car lap1))
+               (memq (car lap0) byte-after-unbind-ops))
+          (byte-compile-log-lap "  %s %s\t-->\t%s %s" lap0 lap1 lap1 lap0)
+          (setcar rest lap1)
+          (setcar (cdr rest) lap0)
+          (setq keep-going t))
+         ;;
+         ;; varbind-X unbind-N         -->  discard unbind-(N-1)
+         ;; save-excursion unbind-N    -->  unbind-(N-1)
+         ;; save-restriction unbind-N  -->  unbind-(N-1)
+         ;;
+         ((and (eq 'byte-unbind (car lap1))
+               (memq (car lap0) '(byte-varbind byte-save-excursion
+                                  byte-save-restriction))
+               (< 0 (cdr lap1)))
+          (if (zerop (setcdr lap1 (1- (cdr lap1))))
+              (delq lap1 rest))
+          (if (eq (car lap0) 'byte-varbind)
+              (setcar rest (cons 'byte-discard 0))
+            (setq lap (delq lap0 lap)))
+          (byte-compile-log-lap "  %s %s\t-->\t%s %s"
+                                lap0 (cons (car lap1) (1+ (cdr lap1)))
+                                (if (eq (car lap0) 'byte-varbind)
+                                    (car rest)
+                                  (car (cdr rest)))
+                                (if (and (/= 0 (cdr lap1))
+                                         (eq (car lap0) 'byte-varbind))
+                                    (car (cdr rest))
+                                  ""))
+          (setq keep-going t))
+         ;;
+         ;; goto*-X ... X: goto-Y  --> goto*-Y
+         ;; goto-X ...  X: return  --> return
+         ;;
+         ((and (memq (car lap0) byte-goto-ops)
+               (memq (car (setq tmp (nth 1 (memq (cdr lap0) lap))))
+                     '(byte-goto byte-return)))
+          (cond ((and (not (eq tmp lap0))
+                      (or (eq (car lap0) 'byte-goto)
+                          (eq (car tmp) 'byte-goto)))
+                 (byte-compile-log-lap "  %s [%s]\t-->\t%s"
+                                       (car lap0) tmp tmp)
+                 (if (eq (car tmp) 'byte-return)
+                     (setcar lap0 'byte-return))
+                 (setcdr lap0 (cdr tmp))
+                 (setq keep-going t))))
+         ;;
+         ;; goto-*-else-pop X ... X: goto-if-* --> whatever
+         ;; goto-*-else-pop X ... X: discard --> whatever
+         ;;
+         ((and (memq (car lap0) '(byte-goto-if-nil-else-pop
+                                  byte-goto-if-not-nil-else-pop))
+               (memq (car (car (setq tmp (cdr (memq (cdr lap0) lap)))))
+                     (eval-when-compile
+                       (cons 'byte-discard byte-conditional-ops)))
+               (not (eq lap0 (car tmp))))
+          (setq tmp2 (car tmp))
+          (setq tmp3 (assq (car lap0) '((byte-goto-if-nil-else-pop
+                                         byte-goto-if-nil)
+                                        (byte-goto-if-not-nil-else-pop
+                                         byte-goto-if-not-nil))))
+          (if (memq (car tmp2) tmp3)
+              (progn (setcar lap0 (car tmp2))
+                     (setcdr lap0 (cdr tmp2))
+                     (byte-compile-log-lap "  %s-else-pop [%s]\t-->\t%s"
+                                           (car lap0) tmp2 lap0))
+            ;; Get rid of the -else-pop's and jump one step further.
+            (or (eq 'TAG (car (nth 1 tmp)))
+                (setcdr tmp (cons (byte-compile-make-tag)
+                                  (cdr tmp))))
+            (byte-compile-log-lap "  %s [%s]\t-->\t%s <skip>"
+                                  (car lap0) tmp2 (nth 1 tmp3))
+            (setcar lap0 (nth 1 tmp3))
+            (setcdr lap0 (nth 1 tmp)))
+          (setq keep-going t))
+         ;;
+         ;; const goto-X ... X: goto-if-* --> whatever
+         ;; const goto-X ... X: discard   --> whatever
+         ;;
+         ((and (eq (car lap0) 'byte-constant)
+               (eq (car lap1) 'byte-goto)
+               (memq (car (car (setq tmp (cdr (memq (cdr lap1) lap)))))
+                     (eval-when-compile
+                       (cons 'byte-discard byte-conditional-ops)))
+               (not (eq lap1 (car tmp))))
+          (setq tmp2 (car tmp))
+          (cond ((when (consp (cdr lap0))
+                   (memq (car tmp2)
+                         (if (null (car (cdr lap0)))
+                             '(byte-goto-if-nil byte-goto-if-nil-else-pop)
+                           '(byte-goto-if-not-nil
+                             byte-goto-if-not-nil-else-pop))))
+                 (byte-compile-log-lap "  %s goto [%s]\t-->\t%s %s"
+                                       lap0 tmp2 lap0 tmp2)
+                 (setcar lap1 (car tmp2))
+                 (setcdr lap1 (cdr tmp2))
+                 ;; Let next step fix the (const,goto-if*) sequence.
+                 (setq rest (cons nil rest))
+                 (setq keep-going t))
+                ((or (consp (cdr lap0))
+                     (eq (car tmp2) 'byte-discard))
+                 ;; Jump one step further
+                 (byte-compile-log-lap
+                  "  %s goto [%s]\t-->\t<deleted> goto <skip>"
+                  lap0 tmp2)
                  (or (eq 'TAG (car (nth 1 tmp)))
                      (setcdr tmp (cons (byte-compile-make-tag)
                                        (cdr tmp))))
-                 (byte-compile-log-lap "  %s [%s]\t-->\t%s <skip>"
-                                       (car lap0) tmp2 (nth 1 tmp3))
-                 (setcar lap0 (nth 1 tmp3))
-                 (setcdr lap0 (nth 1 tmp)))
-               (setq keep-going t))
-              ;;
-              ;; const goto-X ... X: goto-if-* --> whatever
-              ;; const goto-X ... X: discard   --> whatever
-              ;;
-              ((and (eq (car lap0) 'byte-constant)
-                    (eq (car lap1) 'byte-goto)
-                    (memq (car (car (setq tmp (cdr (memq (cdr lap1) lap)))))
-                          (eval-when-compile
-                            (cons 'byte-discard byte-conditional-ops)))
-                    (not (eq lap1 (car tmp))))
-               (setq tmp2 (car tmp))
-               (cond ((when (consp (cdr lap0))
-                        (memq (car tmp2)
-                              (if (null (car (cdr lap0)))
-                                  '(byte-goto-if-nil byte-goto-if-nil-else-pop)
-                                '(byte-goto-if-not-nil
-                                  byte-goto-if-not-nil-else-pop))))
-                      (byte-compile-log-lap "  %s goto [%s]\t-->\t%s %s"
-                                            lap0 tmp2 lap0 tmp2)
-                      (setcar lap1 (car tmp2))
-                      (setcdr lap1 (cdr tmp2))
-                      ;; Let next step fix the (const,goto-if*) sequence.
-                      (setq rest (cons nil rest))
-                      (setq keep-going t))
-                     ((or (consp (cdr lap0))
-                          (eq (car tmp2) 'byte-discard))
-                      ;; Jump one step further
-                      (byte-compile-log-lap
-                       "  %s goto [%s]\t-->\t<deleted> goto <skip>"
-                       lap0 tmp2)
-                      (or (eq 'TAG (car (nth 1 tmp)))
-                          (setcdr tmp (cons (byte-compile-make-tag)
-                                            (cdr tmp))))
-                      (setcdr lap1 (car (cdr tmp)))
-                      (setq lap (delq lap0 lap))
-                      (setq keep-going t))))
-              ;;
-              ;; X: varref-Y    ...     varset-Y goto-X  -->
-              ;; X: varref-Y Z: ... dup varset-Y goto-Z
-              ;; (varset-X goto-BACK, BACK: varref-X --> copy the varref down.)
-              ;; (This is so usual for while loops that it is worth handling).
-              ;;
-              ;; Here again, we could do it for stack-ref/stack-set, but
-              ;; that's replacing a stack-ref-Y with a stack-ref-0, which
-              ;; is a very minor improvement (if any), at the cost of
-              ;; more stack use and more byte-code.  Let's not do it.
-              ;;
-              ((and (eq (car lap1) 'byte-varset)
-                    (eq (car lap2) 'byte-goto)
-                    (not (memq (cdr lap2) rest)) ;Backwards jump
-                    (eq (car (car (setq tmp (cdr (memq (cdr lap2) lap)))))
-                        'byte-varref)
-                    (eq (cdr (car tmp)) (cdr lap1))
-                    (not (memq (car (cdr lap1)) byte-boolean-vars)))
-               ;;(byte-compile-log-lap "  Pulled %s to end of loop" (car tmp))
-               (let ((newtag (byte-compile-make-tag)))
-                 (byte-compile-log-lap
-                  "  %s: %s ... %s %s\t-->\t%s: %s %s: ... %s %s %s"
-                  (nth 1 (cdr lap2)) (car tmp)
-                  lap1 lap2
-                  (nth 1 (cdr lap2)) (car tmp)
-                  (nth 1 newtag) 'byte-dup lap1
-                  (cons 'byte-goto newtag)
-                  )
-                 (setcdr rest (cons (cons 'byte-dup 0) (cdr rest)))
-                 (setcdr tmp (cons (setcdr lap2 newtag) (cdr tmp))))
-               (setq add-depth 1)
-               (setq keep-going t))
-              ;;
-              ;; goto-X Y: ... X: goto-if*-Y  -->  goto-if-not-*-X+1 Y:
-              ;; (This can pull the loop test to the end of the loop)
-              ;;
-              ((and (eq (car lap0) 'byte-goto)
-                    (eq (car lap1) 'TAG)
-                    (eq lap1
-                        (cdr (car (setq tmp (cdr (memq (cdr lap0) lap))))))
-                    (memq (car (car tmp))
-                          '(byte-goto byte-goto-if-nil byte-goto-if-not-nil
-                                      byte-goto-if-nil-else-pop)))
-;;             (byte-compile-log-lap "  %s %s, %s %s  --> moved conditional"
-;;                                   lap0 lap1 (cdr lap0) (car tmp))
-               (let ((newtag (byte-compile-make-tag)))
-                 (byte-compile-log-lap
-                  "%s %s: ... %s: %s\t-->\t%s ... %s:"
-                  lap0 (nth 1 lap1) (nth 1 (cdr lap0)) (car tmp)
-                  (cons (cdr (assq (car (car tmp))
-                                   '((byte-goto-if-nil . byte-goto-if-not-nil)
-                                     (byte-goto-if-not-nil . byte-goto-if-nil)
-                                     (byte-goto-if-nil-else-pop .
-                                      byte-goto-if-not-nil-else-pop)
-                                     (byte-goto-if-not-nil-else-pop .
-                                      byte-goto-if-nil-else-pop))))
-                        newtag)
-
-                  (nth 1 newtag)
-                  )
-                 (setcdr tmp (cons (setcdr lap0 newtag) (cdr tmp)))
-                 (if (eq (car (car tmp)) 'byte-goto-if-nil-else-pop)
-                     ;; We can handle this case but not the -if-not-nil case,
-                     ;; because we won't know which non-nil constant to push.
-                   (setcdr rest (cons (cons 'byte-constant
-                                            (byte-compile-get-constant nil))
-                                      (cdr rest))))
-               (setcar lap0 (nth 1 (memq (car (car tmp))
-                                         '(byte-goto-if-nil-else-pop
-                                           byte-goto-if-not-nil
-                                           byte-goto-if-nil
-                                           byte-goto-if-not-nil
-                                           byte-goto byte-goto))))
-               )
-               (setq keep-going t))
-              )
+                 (setcdr lap1 (car (cdr tmp)))
+                 (setq lap (delq lap0 lap))
+                 (setq keep-going t))))
+         ;;
+         ;; X: varref-Y    ...     varset-Y goto-X  -->
+         ;; X: varref-Y Z: ... dup varset-Y goto-Z
+         ;; (varset-X goto-BACK, BACK: varref-X --> copy the varref down.)
+         ;; (This is so usual for while loops that it is worth handling).
+         ;;
+         ;; Here again, we could do it for stack-ref/stack-set, but
+         ;; that's replacing a stack-ref-Y with a stack-ref-0, which
+         ;; is a very minor improvement (if any), at the cost of
+         ;; more stack use and more byte-code.  Let's not do it.
+         ;;
+         ((and (eq (car lap1) 'byte-varset)
+               (eq (car lap2) 'byte-goto)
+               (not (memq (cdr lap2) rest)) ;Backwards jump
+               (eq (car (car (setq tmp (cdr (memq (cdr lap2) lap)))))
+                   'byte-varref)
+               (eq (cdr (car tmp)) (cdr lap1))
+               (not (memq (car (cdr lap1)) byte-boolean-vars)))
+          ;;(byte-compile-log-lap "  Pulled %s to end of loop" (car tmp))
+          (let ((newtag (byte-compile-make-tag)))
+            (byte-compile-log-lap
+             "  %s: %s ... %s %s\t-->\t%s: %s %s: ... %s %s %s"
+             (nth 1 (cdr lap2)) (car tmp)
+             lap1 lap2
+             (nth 1 (cdr lap2)) (car tmp)
+             (nth 1 newtag) 'byte-dup lap1
+             (cons 'byte-goto newtag)
+             )
+            (setcdr rest (cons (cons 'byte-dup 0) (cdr rest)))
+            (setcdr tmp (cons (setcdr lap2 newtag) (cdr tmp))))
+          (setq add-depth 1)
+          (setq keep-going t))
+         ;;
+         ;; goto-X Y: ... X: goto-if*-Y  -->  goto-if-not-*-X+1 Y:
+         ;; (This can pull the loop test to the end of the loop)
+         ;;
+         ((and (eq (car lap0) 'byte-goto)
+               (eq (car lap1) 'TAG)
+               (eq lap1
+                   (cdr (car (setq tmp (cdr (memq (cdr lap0) lap))))))
+               (memq (car (car tmp))
+                     '(byte-goto byte-goto-if-nil byte-goto-if-not-nil
+                       byte-goto-if-nil-else-pop)))
+          ;;           (byte-compile-log-lap "  %s %s, %s %s  --> moved conditional"
+          ;;                                 lap0 lap1 (cdr lap0) (car tmp))
+          (let ((newtag (byte-compile-make-tag)))
+            (byte-compile-log-lap
+             "%s %s: ... %s: %s\t-->\t%s ... %s:"
+             lap0 (nth 1 lap1) (nth 1 (cdr lap0)) (car tmp)
+             (cons (cdr (assq (car (car tmp))
+                              '((byte-goto-if-nil . byte-goto-if-not-nil)
+                                (byte-goto-if-not-nil . byte-goto-if-nil)
+                                (byte-goto-if-nil-else-pop .
+                                                           byte-goto-if-not-nil-else-pop)
+                                (byte-goto-if-not-nil-else-pop .
+                                                               byte-goto-if-nil-else-pop))))
+                   newtag)
+
+             (nth 1 newtag)
+             )
+            (setcdr tmp (cons (setcdr lap0 newtag) (cdr tmp)))
+            (if (eq (car (car tmp)) 'byte-goto-if-nil-else-pop)
+                ;; We can handle this case but not the -if-not-nil case,
+                ;; because we won't know which non-nil constant to push.
+                (setcdr rest (cons (cons 'byte-constant
+                                         (byte-compile-get-constant nil))
+                                   (cdr rest))))
+            (setcar lap0 (nth 1 (memq (car (car tmp))
+                                      '(byte-goto-if-nil-else-pop
+                                        byte-goto-if-not-nil
+                                        byte-goto-if-nil
+                                        byte-goto-if-not-nil
+                                        byte-goto byte-goto))))
+            )
+          (setq keep-going t))
+
+         ;;
+         ;; stack-set-M [discard/discardN ...]  -->  discardN-preserve-tos
+         ;; stack-set-M [discard/discardN ...]  -->  discardN
+         ;;
+         ((and (eq (car lap0) 'byte-stack-set)
+               (memq (car lap1) '(byte-discard byte-discardN))
+               (progn
+                 ;; See if enough discard operations follow to expose or
+                 ;; destroy the value stored by the stack-set.
+                 (setq tmp (cdr rest))
+                 (setq tmp2 (1- (cdr lap0)))
+                 (setq tmp3 0)
+                 (while (memq (car (car tmp)) '(byte-discard byte-discardN))
+                   (setq tmp3
+                         (+ tmp3 (if (eq (car (car tmp)) 'byte-discard)
+                                     1
+                                   (cdr (car tmp)))))
+                   (setq tmp (cdr tmp)))
+                 (>= tmp3 tmp2)))
+          ;; Do the optimization.
+          (setq lap (delq lap0 lap))
+          (setcar lap1
+                  (if (= tmp2 tmp3)
+                      ;; The value stored is the new TOS, so pop one more
+                      ;; value (to get rid of the old value) using the
+                      ;; TOS-preserving discard operator.
+                      'byte-discardN-preserve-tos
+                    ;; Otherwise, the value stored is lost, so just use a
+                    ;; normal discard.
+                    'byte-discardN))
+          (setcdr lap1 (1+ tmp3))
+          (setcdr (cdr rest) tmp)
+          (byte-compile-log-lap "  %s [discard/discardN]...\t-->\t%s"
+                                lap0 lap1))
+
+         ;;
+         ;; discardN-preserve-tos return  -->  return
+         ;; dup return  -->  return
+         ;; stack-set-N return  -->  return     ; where N is TOS-1
+         ;;
+         ((and (eq (car lap1) 'byte-return)
+               (or (memq (car lap0) '(byte-discardN-preserve-tos byte-dup))
+                   (and (eq (car lap0) 'byte-stack-set)
+                        (= (cdr lap0) 1))))
+          (setq keep-going t)
+          ;; The byte-code interpreter will pop the stack for us, so
+          ;; we can just leave stuff on it.
+          (setq lap (delq lap0 lap))
+          (byte-compile-log-lap "  %s %s\t-->\t%s" lap0 lap1 lap1))
+
+         ;;
+         ;; goto-X ... X: discard  ==>  discard goto-Y ... X: discard Y:
+         ;;
+         ((and (eq (car lap0) 'byte-goto)
+               (setq tmp (cdr (memq (cdr lap0) lap)))
+               (memq (caar tmp) '(byte-discard byte-discardN
+                                  byte-discardN-preserve-tos)))
+          (byte-compile-log-lap
+           "  goto-X .. X: \t-->\t%s goto-X.. X: %s Y:"
+           (car tmp) (car tmp))
+          (setq keep-going t)
+          (let* ((newtag (byte-compile-make-tag))
+                 ;; Make a copy, since we sometimes modify insts in-place!
+                 (newdiscard (cons (caar tmp) (cdar tmp)))
+                 (newjmp (cons (car lap0) newtag)))
+            (push newtag (cdr tmp))     ;Push new tag after the discard.
+            (setcar rest newdiscard)
+            (push newjmp (cdr rest))))
+
+         ;;
+         ;; const discardN-preserve-tos ==> discardN const
+         ;;
+         ((and (eq (car lap0) 'byte-constant)
+               (eq (car lap1) 'byte-discardN-preserve-tos))
+          (setq keep-going t)
+          (let ((newdiscard (cons 'byte-discardN (cdr lap1))))
+            (byte-compile-log-lap
+             "  %s %s\t-->\t%s %s" lap0 lap1 newdiscard lap0)
+            (setf (car rest) newdiscard)
+            (setf (cadr rest) lap0)))
+         )
         (setq rest (cdr rest)))
       )
     ;; Cleanup stage:
@@ -2086,41 +2168,6 @@ If FOR-EFFECT is non-nil, the return value is assumed to be of no importance."
              (setcdr lap1 (+ (cdr lap1) (cdr lap0))))
 
             ;;
-            ;; stack-set-M [discard/discardN ...]  -->  discardN-preserve-tos
-            ;; stack-set-M [discard/discardN ...]  -->  discardN
-            ;;
-            ((and (eq (car lap0) 'byte-stack-set)
-                  (memq (car lap1) '(byte-discard byte-discardN))
-                  (progn
-                    ;; See if enough discard operations follow to expose or
-                    ;; destroy the value stored by the stack-set.
-                    (setq tmp (cdr rest))
-                    (setq tmp2 (1- (cdr lap0)))
-                    (setq tmp3 0)
-                    (while (memq (car (car tmp)) '(byte-discard byte-discardN))
-                      (setq tmp3
-                            (+ tmp3 (if (eq (car (car tmp)) 'byte-discard)
-                                        1
-                                      (cdr (car tmp)))))
-                      (setq tmp (cdr tmp)))
-                    (>= tmp3 tmp2)))
-             ;; Do the optimization.
-             (setq lap (delq lap0 lap))
-             (setcar lap1
-                     (if (= tmp2 tmp3)
-                         ;; The value stored is the new TOS, so pop one more
-                         ;; value (to get rid of the old value) using the
-                         ;; TOS-preserving discard operator.
-                         'byte-discardN-preserve-tos
-                       ;; Otherwise, the value stored is lost, so just use a
-                       ;; normal discard.
-                       'byte-discardN))
-             (setcdr lap1 (1+ tmp3))
-             (setcdr (cdr rest) tmp)
-             (byte-compile-log-lap "  %s [discard/discardN]...\t-->\t%s"
-                                   lap0 lap1))
-
-            ;;
             ;; discard/discardN/discardN-preserve-tos-X discard/discardN-Y  -->
             ;; discardN-(X+Y)
             ;;
@@ -2147,20 +2194,6 @@ If FOR-EFFECT is non-nil, the return value is assumed to be of no importance."
              (setq lap (delq lap0 lap))
              (setcdr lap1 (+ (cdr lap0) (cdr lap1)))
              (byte-compile-log-lap "  %s %s\t-->\t%s" lap0 lap1 (car rest)))
-
-            ;;
-            ;; discardN-preserve-tos return  -->  return
-            ;; dup return  -->  return
-            ;; stack-set-N return  -->  return     ; where N is TOS-1
-            ;;
-            ((and (eq (car lap1) 'byte-return)
-                  (or (memq (car lap0) '(byte-discardN-preserve-tos byte-dup))
-                      (and (eq (car lap0) 'byte-stack-set)
-                           (= (cdr lap0) 1))))
-             ;; The byte-code interpreter will pop the stack for us, so
-             ;; we can just leave stuff on it.
-             (setq lap (delq lap0 lap))
-             (byte-compile-log-lap "  %s %s\t-->\t%s" lap0 lap1 lap1))
             )
       (setq rest (cdr rest)))
     (setq byte-compile-maxdepth (+ byte-compile-maxdepth add-depth)))
diff --git a/lisp/emacs-lisp/byte-run.el b/lisp/emacs-lisp/byte-run.el
index 3ed299864b7..a3ad43038e7 100644
--- a/lisp/emacs-lisp/byte-run.el
+++ b/lisp/emacs-lisp/byte-run.el
@@ -238,8 +238,11 @@ The return value is undefined.
                   #'(lambda (x)
                       (let ((f (cdr (assq (car x) macro-declarations-alist))))
                         (if f (apply (car f) name arglist (cdr x))
-                          (message "Warning: Unknown macro property %S in %S"
-                                   (car x) name))))
+                          (macroexp--warn-and-return
+                           (format-message
+                            "Unknown macro property %S in %S"
+                            (car x) name)
+                           nil))))
                   decls)))
            ;; Refresh font-lock if this is a new macro, or it is an
            ;; existing macro whose 'no-font-lock-keyword declaration
@@ -307,9 +310,12 @@ The return value is undefined.
                                 (cdr body)
                               body)))
                     nil)
-                   (t (message "Warning: Unknown defun property `%S' in %S"
-                               (car x) name)))))
-                   decls))
+                   (t
+                    (macroexp--warn-and-return
+                     (format-message "Unknown defun property `%S' in %S"
+                                     (car x) name)
+                     nil)))))
+            decls))
           (def (list 'defalias
                      (list 'quote name)
                      (list 'function
diff --git a/lisp/emacs-lisp/bytecomp.el b/lisp/emacs-lisp/bytecomp.el
index 54f8301b085..c0f8db69e51 100644
--- a/lisp/emacs-lisp/bytecomp.el
+++ b/lisp/emacs-lisp/bytecomp.el
@@ -2577,7 +2577,8 @@ list that represents a doc string reference.
   (when (memq sym byte-compile-lexical-variables)
     (setq byte-compile-lexical-variables
           (delq sym byte-compile-lexical-variables))
-    (byte-compile-warn "Variable `%S' declared after its first use" sym))
+    (when (byte-compile-warning-enabled-p 'lexical sym)
+      (byte-compile-warn "Variable `%S' declared after its first use" sym)))
   (push sym byte-compile-bound-variables)
   (push sym byte-compile--seen-defvars))
 
diff --git a/lisp/emacs-lisp/checkdoc.el b/lisp/emacs-lisp/checkdoc.el
index 2e204ff7aea..76638ec13b1 100644
--- a/lisp/emacs-lisp/checkdoc.el
+++ b/lisp/emacs-lisp/checkdoc.el
@@ -241,7 +241,12 @@ system.  Possible values are:
   defun       - Spell-check when style checking a single defun.
   buffer      - Spell-check when style checking the whole buffer.
   interactive - Spell-check during any interactive check.
-  t           - Always spell-check."
+  t           - Always spell-check.
+
+There is a list of Lisp-specific words which checkdoc will
+install into Ispell on the fly, but only if Ispell is not already
+running.  Use `ispell-kill-ispell' to make checkdoc restart it
+with these words enabled."
   :type '(choice (const nil)
           (const defun)
           (const buffer)
diff --git a/lisp/emacs-lisp/ert.el b/lisp/emacs-lisp/ert.el
index 58517549454..fdbf95319ff 100644
--- a/lisp/emacs-lisp/ert.el
+++ b/lisp/emacs-lisp/ert.el
@@ -487,7 +487,7 @@ Errors during evaluation are caught and handled like nil."
 Returns nil if they are."
   (if (not (eq (type-of a) (type-of b)))
       `(different-types ,a ,b)
-    (pcase-exhaustive a
+    (pcase a
       ((pred consp)
        (let ((a-length (proper-list-p a))
              (b-length (proper-list-p b)))
@@ -538,7 +538,7 @@ Returns nil if they are."
                   for xi = (ert--explain-equal-rec ai bi)
                   do (when xi (cl-return `(array-elt ,i ,xi)))
                   finally (cl-assert (equal a b) t))))
-      ((pred atom)
+      (_
        (if (not (equal a b))
            (if (and (symbolp a) (symbolp b) (string= a b))
                `(different-symbols-with-the-same-name ,a ,b)
diff --git a/lisp/emacs-lisp/macroexp.el b/lisp/emacs-lisp/macroexp.el
index 37844977f8f..aa49bccc8d0 100644
--- a/lisp/emacs-lisp/macroexp.el
+++ b/lisp/emacs-lisp/macroexp.el
@@ -127,7 +127,7 @@ and also to avoid outputting the warning during normal execution."
     (cond
      ((null msg) form)
      ((macroexp--compiling-p)
-      (if (gethash form macroexp--warned)
+      (if (and (consp form) (gethash form macroexp--warned))
           ;; Already wrapped this exp with a warning: avoid inf-looping
           ;; where we keep adding the same warning onto `form' because
           ;; macroexpand-all gets right back to macroexpanding `form'.
@@ -138,9 +138,10 @@ and also to avoid outputting the warning during normal execution."
            ,form)))
      (t
       (unless compile-only
-        (message "%s%s" (if (stringp load-file-name)
-                            (concat (file-relative-name load-file-name) ": ")
-                          "")
+        (message "%sWarning: %s"
+                 (if (stringp load-file-name)
+                     (concat (file-relative-name load-file-name) ": ")
+                   "")
                  msg))
       form))))
 
@@ -180,8 +181,9 @@ and also to avoid outputting the warning during normal execution."
 
 (defun macroexp-macroexpand (form env)
   "Like `macroexpand' but checking obsolescence."
-  (let ((new-form
-         (macroexpand form env)))
+  (let* ((macroexpand-all-environment env)
+         (new-form
+          (macroexpand form env)))
     (if (and (not (eq form new-form))   ;It was a macro call.
              (car-safe form)
              (symbolp (car form))
diff --git a/lisp/emacs-lisp/package.el b/lisp/emacs-lisp/package.el
index 125fbe09961..9f155bad394 100644
--- a/lisp/emacs-lisp/package.el
+++ b/lisp/emacs-lisp/package.el
@@ -3288,9 +3288,9 @@ To unhide a package, type
 `\\[customize-variable] RET package-hidden-regexps'.
 
 Type \\[package-menu-toggle-hiding] to toggle package hiding."
+  (declare (interactive-only "change `package-hidden-regexps' instead."))
   (interactive)
   (package--ensure-package-menu-mode)
-  (declare (interactive-only "change `package-hidden-regexps' instead."))
   (let* ((name (when (derived-mode-p 'package-menu-mode)
                  (concat "\\`" (regexp-quote (symbol-name (package-desc-name
                                                            (tabulated-list-get-id))))
diff --git a/lisp/emacs-lisp/pcase.el b/lisp/emacs-lisp/pcase.el
index 72ea1ba0188..bfd577c5d14 100644
--- a/lisp/emacs-lisp/pcase.el
+++ b/lisp/emacs-lisp/pcase.el
@@ -39,10 +39,10 @@
 ;; - along these lines, provide patterns to match CL structs.
 ;; - provide something like (setq VAR) so a var can be set rather than
 ;;   let-bound.
-;; - provide a way to fallthrough to subsequent cases (not sure what I meant by
-;;   this :-()
+;; - provide a way to fallthrough to subsequent cases
+;;   (e.g. Like Racket's (=> ID).
 ;; - try and be more clever to reduce the size of the decision tree, and
-;;   to reduce the number of leaves that need to be turned into function:
+;;   to reduce the number of leaves that need to be turned into functions:
 ;;   - first, do the tests shared by all remaining branches (it will have
 ;;     to be performed anyway, so better do it first so it's shared).
 ;;   - then choose the test that discriminates more (?).
@@ -97,11 +97,15 @@
 (declare-function get-edebug-spec "edebug" (symbol))
 (declare-function edebug-match "edebug" (cursor specs))
 
+(defun pcase--get-macroexpander (s)
+  "Return the macroexpander for pcase pattern head S, or nil"
+  (get s 'pcase-macroexpander))
+
 (defun pcase--edebug-match-macro (cursor)
   (let (specs)
     (mapatoms
      (lambda (s)
-       (let ((m (get s 'pcase-macroexpander)))
+       (let ((m (pcase--get-macroexpander s)))
          (when (and m (get-edebug-spec m))
            (push (cons (symbol-name s) (get-edebug-spec m))
                  specs)))))
@@ -128,6 +132,7 @@ PATTERN matches.  PATTERN can take one of the forms:
                    If a SYMBOL is used twice in the same pattern
                    the second occurrence becomes an `eq'uality test.
   (pred FUN)       matches if FUN called on EXPVAL returns non-nil.
+  (pred (not FUN)) matches if FUN called on EXPVAL returns nil.
   (app FUN PAT)    matches if FUN called on EXPVAL matches PAT.
   (guard BOOLEXP)  matches if BOOLEXP evaluates to non-nil.
   (let PAT EXPR)   matches if EXPR matches PAT.
@@ -193,7 +198,7 @@ Emacs Lisp manual for more information and examples."
       (let (more)
         ;; Collect all the extensions.
         (mapatoms (lambda (symbol)
-                    (let ((me (get symbol 'pcase-macroexpander)))
+                    (let ((me (pcase--get-macroexpander symbol)))
                       (when me
                         (push (cons symbol me)
                               more)))))
@@ -424,7 +429,7 @@ of the elements of LIST is performed as if by `pcase-let'.
      ((eq head 'let) `(let ,(pcase--macroexpand (cadr pat)) ,@(cddr pat)))
      ((eq head 'app) `(app ,(nth 1 pat) ,(pcase--macroexpand (nth 2 pat))))
      (t
-      (let* ((expander (get head 'pcase-macroexpander))
+      (let* ((expander (pcase--get-macroexpander head))
              (npat (if expander (apply expander (cdr pat)))))
         (if (null npat)
             (error (if expander
@@ -658,6 +663,14 @@ MATCH is the pattern that needs to be matched, of the form:
     '(:pcase--succeed . nil))))
 
 (defun pcase--split-pred (vars upat pat)
+  "Indicate the overlap or mutual-exclusion between UPAT and PAT.
+More specifically retuns a pair (A . B) where A indicates whether PAT
+can match when UPAT has matched, and B does the same for the case
+where UPAT failed to match.
+A and B can be one of:
+- nil if we don't know
+- `:pcase--fail' if UPAT match's result implies that PAT can't match
+- `:pcase--succeed' if UPAT match's result implies that PAT matches"
   (let (test)
     (cond
      ((and (equal upat pat)
@@ -670,6 +683,19 @@ MATCH is the pattern that needs to be matched, of the form:
                ;; and catch at least the easy cases such as (bug#14773).
                (not (macroexp--fgrep (mapcar #'car vars) (cadr upat)))))
       '(:pcase--succeed . :pcase--fail))
+     ;; In case UPAT is of the form (pred (not PRED))
+     ((and (eq 'pred (car upat)) (eq 'not (car-safe (cadr upat))))
+      (let* ((test (cadr (cadr upat)))
+             (res (pcase--split-pred vars `(pred ,test) pat)))
+        (cons (cdr res) (car res))))
+     ;; In case PAT is of the form (pred (not PRED))
+     ((and (eq 'pred (car-safe pat)) (eq 'not (car-safe (cadr pat))))
+      (let* ((test (cadr (cadr pat)))
+             (res (pcase--split-pred vars upat `(pred ,test)))
+             (reverse (lambda (x) (cond ((eq x :pcase--succeed) :pcase--fail)
+                                   ((eq x :pcase--fail) :pcase--succeed)))))
+        (cons (funcall reverse (car res))
+              (funcall reverse (cdr res)))))
      ((and (eq 'pred (car upat))
            (let ((otherpred
                   (cond ((eq 'pred (car-safe pat)) (cadr pat))
@@ -728,8 +754,10 @@ MATCH is the pattern that needs to be matched, of the form:
 
 (defun pcase--funcall (fun arg vars)
   "Build a function call to FUN with arg ARG."
-  (if (symbolp fun)
-      `(,fun ,arg)
+  (cond
+   ((symbolp fun) `(,fun ,arg))
+   ((eq 'not (car-safe fun)) `(not ,(pcase--funcall (cadr fun) arg vars)))
+   (t
     (let* (;; `env' is an upper bound on the bindings we need.
            (env (mapcar (lambda (x) (list (car x) (cdr x)))
                         (macroexp--fgrep vars fun)))
@@ -747,7 +775,7 @@ MATCH is the pattern that needs to be matched, of the form:
         ;; Let's not replace `vars' in `fun' since it's
         ;; too difficult to do it right, instead just
         ;; let-bind `vars' around `fun'.
-        `(let* ,env ,call)))))
+        `(let* ,env ,call))))))
 
 (defun pcase--eval (exp vars)
   "Build an expression that will evaluate EXP."
diff --git a/lisp/emacs-lisp/radix-tree.el b/lisp/emacs-lisp/radix-tree.el
index 6a483a6d498..0905ac608bb 100644
--- a/lisp/emacs-lisp/radix-tree.el
+++ b/lisp/emacs-lisp/radix-tree.el
@@ -198,9 +198,10 @@ If not found, return nil."
   (pcase-defmacro radix-tree-leaf (vpat)
     "Pattern which matches a radix-tree leaf.
 The pattern VPAT is matched against the leaf's carried value."
-    ;; FIXME: We'd like to use a negative pattern (not consp), but pcase
-    ;; doesn't support it.  Using `atom' works but generates sub-optimal code.
-    `(or `(t . ,,vpat) (and (pred atom) ,vpat))))
+    ;; We used to use `(pred atom)', but `pcase' doesn't understand that
+    ;; `atom' is equivalent to the negation of `consp' and hence generates
+    ;; suboptimal code.
+    `(or `(t . ,,vpat) (and (pred (not consp)) ,vpat))))
 
 (defun radix-tree-iter-subtrees (tree fun)
   "Apply FUN to every immediate subtree of radix TREE.
diff --git a/lisp/emacs-lisp/subr-x.el b/lisp/emacs-lisp/subr-x.el
index b90227da42f..a4514454c0b 100644
--- a/lisp/emacs-lisp/subr-x.el
+++ b/lisp/emacs-lisp/subr-x.el
@@ -389,6 +389,28 @@ it makes no sense to convert it to a string using
                 (set-buffer source-buffer)
                 (replace-buffer-contents tmp-buffer max-secs max-costs)))))))))
 
+(defmacro named-let (name bindings &rest body)
+  "Looping construct taken from Scheme.
+Like `let', bind variables in BINDINGS and then evaluate BODY,
+but with the twist that BODY can evaluate itself recursively by
+calling NAME, where the arguments passed to NAME are used
+as the new values of the bound variables in the recursive invocation."
+  (declare (indent 2) (debug (symbolp (&rest (symbolp form)) body)))
+  (require 'cl-lib)
+  (let ((fargs (mapcar (lambda (b) (if (consp b) (car b) b)) bindings))
+        (aargs (mapcar (lambda (b) (if (consp b) (cadr b))) bindings)))
+    ;; According to the Scheme semantics of named let, `name' is not in scope
+    ;; while evaluating the expressions in `bindings', and for this reason, the
+    ;; "initial" function call below needs to be outside of the `cl-labels'.
+    ;; When the "self-tco" eliminates all recursive calls, the `cl-labels'
+    ;; expands to a lambda which the byte-compiler then combines with the
+    ;; funcall to make a `let' so we end up with a plain `while' loop and no
+    ;; remaining `lambda' at all.
+    `(funcall
+      (cl-labels ((,name ,fargs . ,body)) #',name)
+      . ,aargs)))
+
+
 (provide 'subr-x)
 
 ;;; subr-x.el ends here
diff --git a/lisp/emulation/cua-gmrk.el b/lisp/emulation/cua-gmrk.el
index 195bba1f317..6f6b9fce130 100644
--- a/lisp/emulation/cua-gmrk.el
+++ b/lisp/emulation/cua-gmrk.el
@@ -87,9 +87,11 @@
 
 (defun cua-toggle-global-mark (stay)
   "Set or cancel the global marker.
-When the global marker is set, CUA cut and copy commands will automatically
-insert the deleted or copied text before the global marker, even when the
-global marker is in another buffer.
+When the global marker is set, CUA cut and copy commands will
+automatically insert the inserted, deleted or copied text before
+the global marker, even when the global marker is in another
+buffer.
+
 If the global marker isn't set, set the global marker at point in the current
 buffer.  Otherwise jump to the global marker position and cancel it.
 With prefix argument, don't jump to global mark when canceling it."
diff --git a/lisp/epa.el b/lisp/epa.el
index db2b1271473..197cd92f977 100644
--- a/lisp/epa.el
+++ b/lisp/epa.el
@@ -359,8 +359,8 @@ DOC is documentation text to insert at the start."
 
     ;; Find the end of the documentation text at the start.
     ;; Set POINT to where it ends, or nil if ends at eob.
-    (unless (get-text-property point 'epa-list-keys)
-      (setq point (next-single-property-change point 'epa-list-keys)))
+    (unless (get-text-property point 'epa-key)
+      (setq point (next-single-property-change point 'epa-key)))
 
     ;; If caller specified documentation text for that, replace the old
     ;; documentation text (if any) with what was specified.
diff --git a/lisp/facemenu.el b/lisp/facemenu.el
index 2609397b0d9..dc5f8f46aba 100644
--- a/lisp/facemenu.el
+++ b/lisp/facemenu.el
@@ -606,9 +606,14 @@ color.  The function should accept a single argument, the color name."
 
 (defun list-colors-print (list &optional callback)
   (let ((callback-fn
-         (if callback
-             `(lambda (button)
-                (funcall ,callback (button-get button 'color-name))))))
+         ;; Expect CALLBACK to be a function, but allow it to be a form that
+         ;; evaluates to a function, for backward-compatibility.  (Bug#45831)
+         (cond ((functionp callback)
+                (lambda (button)
+                  (funcall callback (button-get button 'color-name))))
+               (callback
+                `(lambda (button)
+                  (funcall ,callback (button-get button 'color-name)))))))
     (dolist (color list)
       (if (consp color)
           (if (cdr color)
diff --git a/lisp/faces.el b/lisp/faces.el
index 4e98338432f..d654b1f0e2a 100644
--- a/lisp/faces.el
+++ b/lisp/faces.el
@@ -2199,7 +2199,7 @@ the above example."
                 (not (funcall pred type)))
       ;; Strip off last hyphen and what follows, then try again
       (setq type
-            (if (setq hyphend (string-match-p "[-_][^-_]+$" type))
+            (if (setq hyphend (string-match-p "[-_.][^-_.]+$" type))
                 (substring type 0 hyphend)
               nil))))
   type)
diff --git a/lisp/files.el b/lisp/files.el
index 695afae8c56..e9be7c7e75c 100644
--- a/lisp/files.el
+++ b/lisp/files.el
@@ -4067,7 +4067,7 @@ Return the new variables list."
                      (subdirs (assq 'subdirs alist)))
                 (if (or (not subdirs)
                         (progn
-                          (setq alist (delq subdirs alist))
+                          (setq alist (remq subdirs alist))
                           (cdr-safe subdirs))
                         ;; TODO someone might want to extend this to allow
                         ;; integer values for subdir, where N means
diff --git a/lisp/font-lock.el b/lisp/font-lock.el
index a51434c38c9..a9fc69d419a 100644
--- a/lisp/font-lock.el
+++ b/lisp/font-lock.el
@@ -1104,8 +1104,8 @@ Called with two arguments BEG and END.")
   "Reinitialize the font-lock machinery and (re-)fontify the buffer.
 This functions is a convenience functions when developing font
 locking for a mode, and is not meant to be called from lisp functions."
-  (interactive)
   (declare (interactive-only t))
+  (interactive)
   ;; Make font-lock recalculate all the mode-specific data.
   (setq font-lock-major-mode nil)
   ;; Make the syntax machinery discard all information.
diff --git a/lisp/frame.el b/lisp/frame.el
index e2d7f21a498..06aab269ddd 100644
--- a/lisp/frame.el
+++ b/lisp/frame.el
@@ -2552,13 +2552,15 @@ Use 0 or negative value to blink forever."
 This starts the timer `blink-cursor-timer', which makes the cursor blink
 if appropriate.  It also arranges to cancel that timer when the next
 command starts, by installing a pre-command hook."
-  (when (null blink-cursor-timer)
+  (cond
+   ((null blink-cursor-mode) (blink-cursor-mode -1))
+   ((null blink-cursor-timer)
     ;; Set up the timer first, so that if this signals an error,
     ;; blink-cursor-end is not added to pre-command-hook.
     (setq blink-cursor-blinks-done 1)
     (blink-cursor--start-timer)
     (add-hook 'pre-command-hook #'blink-cursor-end)
-    (internal-show-cursor nil nil)))
+    (internal-show-cursor nil nil))))
 
 (defun blink-cursor-timer-function ()
   "Timer function of timer `blink-cursor-timer'."
@@ -2615,7 +2617,7 @@ stopped by `blink-cursor-suspend'.  Internally calls
 `blink-cursor--should-blink' and returns its result."
   (let ((should-blink (blink-cursor--should-blink)))
     (when (and should-blink (not blink-cursor-idle-timer))
-      (remove-hook 'post-command-hook 'blink-cursor-check)
+      (remove-hook 'post-command-hook #'blink-cursor-check)
       (blink-cursor--start-idle-timer))
     should-blink))
 
@@ -2637,16 +2639,16 @@ This command is effective only on graphical frames.  On text-only
 terminals, cursor blinking is controlled by the terminal."
   :init-value (not (or noninteractive
                        no-blinking-cursor
-                       (eq system-type 'ms-dos)
-                       (not (display-blink-cursor-p))))
-  :initialize 'custom-initialize-delay
+                       (eq system-type 'ms-dos)))
+  :initialize #'custom-initialize-delay
   :group 'cursor
   :global t
   (blink-cursor-suspend)
   (remove-hook 'after-delete-frame-functions #'blink-cursor--rescan-frames)
   (remove-function after-focus-change-function #'blink-cursor--rescan-frames)
   (when blink-cursor-mode
-    (add-function :after after-focus-change-function #'blink-cursor--rescan-frames)
+    (add-function :after after-focus-change-function
+                  #'blink-cursor--rescan-frames)
     (add-hook 'after-delete-frame-functions #'blink-cursor--rescan-frames)
     (blink-cursor-check)))
 
diff --git a/lisp/gnus/gnus-agent.el b/lisp/gnus/gnus-agent.el
index 56640ea8302..686623029ed 100644
--- a/lisp/gnus/gnus-agent.el
+++ b/lisp/gnus/gnus-agent.el
@@ -1789,6 +1789,7 @@ variables.  Returns the first non-nil value found."
                  . gnus-agent-enable-expiration)
                 (agent-predicate . gnus-agent-predicate)))))))
 
+;; FIXME: This looks an awful lot like `gnus-agent-retrieve-headers'.
 (defun gnus-agent-fetch-headers (group)
   "Fetch interesting headers into the agent.  The group's overview
 file will be updated to include the headers while a list of available
@@ -1810,10 +1811,9 @@ article numbers will be returned."
                                     (cdr active))))
                          (gnus-uncompress-range (gnus-active group)))
                      (gnus-list-of-unread-articles group)))
-         (gnus-decode-encoded-word-function 'identity)
-         (gnus-decode-encoded-address-function 'identity)
          (file (gnus-agent-article-name ".overview" group))
-         (file-name-coding-system nnmail-pathname-coding-system))
+         (file-name-coding-system nnmail-pathname-coding-system)
+         headers fetched-headers)
 
     (unless fetch-all
       ;; Add articles with marks to the list of article headers we want to
@@ -1824,7 +1824,7 @@ article numbers will be returned."
       (dolist (arts (gnus-info-marks (gnus-get-info group)))
         (unless (memq (car arts) '(seen recent killed cache))
           (setq articles (gnus-range-add articles (cdr arts)))))
-      (setq articles (sort (gnus-uncompress-sequence articles) '<)))
+      (setq articles (sort (gnus-uncompress-range articles) '<)))
 
     ;; At this point, I have the list of articles to consider for
     ;; fetching.  This is the list that I'll return to my caller. Some
@@ -1867,38 +1867,52 @@ article numbers will be returned."
          10 "gnus-agent-fetch-headers: undownloaded articles are `%s'"
          (gnus-compress-sequence articles t)))
 
-      (with-current-buffer nntp-server-buffer
-        (if articles
-            (progn
-              (gnus-message 8 "Fetching headers for %s..." group)
-
-              ;; Fetch them.
-              (gnus-make-directory (nnheader-translate-file-chars
-                                    (file-name-directory file) t))
-
-              (unless (eq 'nov (gnus-retrieve-headers articles group))
-                (nnvirtual-convert-headers))
-              (gnus-agent-check-overview-buffer)
-              ;; Move these headers to the overview buffer so that
-              ;; gnus-agent-braid-nov can merge them with the contents
-              ;; of FILE.
-              (copy-to-buffer
-               gnus-agent-overview-buffer (point-min) (point-max))
-              ;; NOTE: Call g-a-brand-nov even when the file does not
-              ;; exist.  As a minimum, it will validate the article
-              ;; numbers already in the buffer.
-              (gnus-agent-braid-nov articles file)
-              (let ((coding-system-for-write
-                     gnus-agent-file-coding-system))
-                (gnus-agent-check-overview-buffer)
-                (write-region (point-min) (point-max) file nil 'silent))
-              (gnus-agent-update-view-total-fetched-for group t)
-              (gnus-agent-save-alist group articles nil)
-              articles)
-          (ignore-errors
-            (erase-buffer)
-            (nnheader-insert-file-contents file)))))
-    articles))
+      ;; Parse known headers from FILE.
+      (if (file-exists-p file)
+          (with-current-buffer gnus-agent-overview-buffer
+            (erase-buffer)
+            (let ((nnheader-file-coding-system
+                   gnus-agent-file-coding-system))
+              (nnheader-insert-nov-file file (car articles))
+              (with-current-buffer nntp-server-buffer
+                (erase-buffer)
+                (insert-buffer-substring gnus-agent-overview-buffer)
+                (setq headers
+                      (gnus-get-newsgroup-headers-xover
+                       articles nil (buffer-local-value
+                                     'gnus-newsgroup-dependencies
+                                     gnus-summary-buffer)
+                       gnus-newsgroup-name)))))
+        (gnus-make-directory (nnheader-translate-file-chars
+                              (file-name-directory file) t)))
+
+      ;; Fetch our new headers.
+      (gnus-message 8 "Fetching headers for %s..." group)
+      (if articles
+          (setq fetched-headers (gnus-fetch-headers articles)))
+
+      ;; Merge two sets of headers.
+      (setq headers
+            (if (and headers fetched-headers)
+                (delete-dups
+                 (sort (append headers (copy-sequence fetched-headers))
+                       (lambda (l r)
+                         (< (mail-header-number l)
+                            (mail-header-number r)))))
+              (or headers fetched-headers)))
+
+      ;; Save the new set of headers to FILE.
+      (let ((coding-system-for-write
+             gnus-agent-file-coding-system))
+        (with-current-buffer gnus-agent-overview-buffer
+          (goto-char (point-max))
+          (mapc #'nnheader-insert-nov fetched-headers)
+          (sort-numeric-fields 1 (point-min) (point-max))
+          (gnus-agent-check-overview-buffer)
+          (write-region (point-min) (point-max) file nil 'silent))
+        (gnus-agent-update-view-total-fetched-for group t)
+        (gnus-agent-save-alist group articles nil)))
+    headers))
 
 (defsubst gnus-agent-read-article-number ()
   "Read the article number at point.
@@ -1924,96 +1938,6 @@ Return nil when a valid article number can not be read."
       (set-buffer nntp-server-buffer)
       (insert-buffer-substring gnus-agent-overview-buffer b e))))
 
-(defun gnus-agent-braid-nov (articles file)
-  "Merge agent overview data with given file.
-Takes unvalidated headers for ARTICLES from
-`gnus-agent-overview-buffer' and validated headers from the given
-FILE and places the combined valid headers into
-`nntp-server-buffer'.  This function can be used, when file
-doesn't exist, to valid the overview buffer."
-  (let (start last)
-    (set-buffer gnus-agent-overview-buffer)
-    (goto-char (point-min))
-    (set-buffer nntp-server-buffer)
-    (erase-buffer)
-    (when (file-exists-p file)
-      (nnheader-insert-file-contents file))
-    (goto-char (point-max))
-    (forward-line -1)
-
-    (unless (or (= (point-min) (point-max))
-                (< (setq last (read (current-buffer))) (car articles)))
-      ;; Old and new overlap -- We do it the hard way.
-      (when (nnheader-find-nov-line (car articles))
-        ;; Replacing existing NOV entry
-        (delete-region (point) (progn (forward-line 1) (point))))
-      (gnus-agent-copy-nov-line (pop articles))
-
-      (ignore-errors
-        (while articles
-          (while (let ((art (read (current-buffer))))
-                   (cond ((< art (car articles))
-                          (forward-line 1)
-                          t)
-                         ((= art (car articles))
-                          (beginning-of-line)
-                          (delete-region
-                           (point) (progn (forward-line 1) (point)))
-                          nil)
-                         (t
-                          (beginning-of-line)
-                          nil))))
-
-          (gnus-agent-copy-nov-line (pop articles)))))
-
-    (goto-char (point-max))
-
-    ;; Append the remaining lines
-    (when articles
-      (when last
-        (set-buffer gnus-agent-overview-buffer)
-        (setq start (point))
-        (set-buffer nntp-server-buffer))
-
-      (let ((p (point)))
-        (insert-buffer-substring gnus-agent-overview-buffer start)
-        (goto-char p))
-
-      (setq last (or last -134217728))
-      (while (catch 'problems
-               (let (sort art)
-                 (while (not (eobp))
-                   (setq art (gnus-agent-read-article-number))
-                   (cond ((not art)
-                          ;; Bad art num - delete this line
-                          (beginning-of-line)
-                          (delete-region (point) (progn (forward-line 1) (point))))
-                         ((< art last)
-                          ;; Art num out of order - enable sort
-                          (setq sort t)
-                          (forward-line 1))
-                         ((= art last)
-                          ;; Bad repeat of art number - delete this line
-                          (beginning-of-line)
-                          (delete-region (point) (progn (forward-line 1) (point))))
-                         (t
-                          ;; Good art num
-                          (setq last art)
-                          (forward-line 1))))
-                 (when sort
-                   ;; something is seriously wrong as we simply shouldn't see out-of-order data.
-                   ;; First, we'll fix the sort.
-                   (sort-numeric-fields 1 (point-min) (point-max))
-
-                   ;; but now we have to consider that we may have duplicate rows...
-                   ;; so reset to beginning of file
-                   (goto-char (point-min))
-                   (setq last -134217728)
-
-                   ;; and throw a code that restarts this scan
-                   (throw 'problems t))
-                 nil))))))
-
 ;; Keeps the compiler from warning about the free variable in
 ;; gnus-agent-read-agentview.
 (defvar gnus-agent-read-agentview)
@@ -2386,10 +2310,9 @@ modified) original contents, they are first saved to their own file."
         (gnus-orphan-score gnus-orphan-score)
         ;; Maybe some other gnus-summary local variables should also
         ;; be put here.
-
+        fetched-headers
         gnus-headers
         gnus-score
-        articles
         predicate info marks
         )
     (unless (gnus-check-group group)
@@ -2410,38 +2333,35 @@ modified) original contents, they are first saved to their own file."
                                          (setq info (gnus-get-info group)))))))
               (when arts
                 (setq marked-articles (nconc (gnus-uncompress-range arts)
-                                             marked-articles))
-                ))))
+                                             marked-articles))))))
         (setq marked-articles (sort marked-articles '<))
 
-        ;; Fetch any new articles from the server
-        (setq articles (gnus-agent-fetch-headers group))
+        (setq gnus-newsgroup-dependencies
+              (or gnus-newsgroup-dependencies
+                  (gnus-make-hashtable)))
 
-        ;; Merge new articles with marked
-        (setq articles (sort (append marked-articles articles) '<))
+        ;; Fetch headers for any new articles from the server.
+        (setq fetched-headers (gnus-agent-fetch-headers group))
 
-        (when articles
-          ;; Parse them and see which articles we want to fetch.
-          (setq gnus-newsgroup-dependencies
-                (or gnus-newsgroup-dependencies
-                    (gnus-make-hashtable (length articles))))
+        (when fetched-headers
           (setq gnus-newsgroup-headers
-                (or gnus-newsgroup-headers
-                    (gnus-get-newsgroup-headers-xover articles nil nil
-                                                      group)))
-          ;; `gnus-agent-overview-buffer' may be killed for
-          ;; timeout reason.  If so, recreate it.
+                (or gnus-newsgroup-headers
+                    fetched-headers)))
+        (when marked-articles
+          ;; `gnus-agent-overview-buffer' may be killed for timeout
+          ;; reason.  If so, recreate it.
           (gnus-agent-create-buffer)
 
           (setq predicate
-                (gnus-get-predicate
-                 (gnus-agent-find-parameter group 'agent-predicate)))
+                (gnus-get-predicate
+                 (gnus-agent-find-parameter group 'agent-predicate)))
+
+          ;; If the selection predicate requires scoring, score each header.
 
-          ;; If the selection predicate requires scoring, score each header
           (unless (memq predicate '(gnus-agent-true gnus-agent-false))
             (let ((score-param
                    (gnus-agent-find-parameter group 'agent-score-file)))
-              ;; Translate score-param into real one
+              ;; Translate score-param into real one.
               (cond
                ((not score-param))
                ((eq score-param 'file)
@@ -3661,11 +3581,9 @@ has been fetched."
 (defun gnus-agent-retrieve-headers (articles group &optional fetch-old)
   (save-excursion
     (gnus-agent-create-buffer)
-    (let ((gnus-decode-encoded-word-function 'identity)
-          (gnus-decode-encoded-address-function 'identity)
-          (file (gnus-agent-article-name ".overview" group))
-          uncached-articles
-          (file-name-coding-system nnmail-pathname-coding-system))
+    (let ((file (gnus-agent-article-name ".overview" group))
+          (file-name-coding-system nnmail-pathname-coding-system)
+          uncached-articles headers fetched-headers)
       (gnus-make-directory (nnheader-translate-file-chars
                             (file-name-directory file) t))
 
@@ -3676,122 +3594,63 @@ has been fetched."
                                 1)
                               (car (last articles))))))
 
-      ;; Populate temp buffer with known headers
+      ;; See if we've got cached headers for ARTICLES and put them in
+      ;; HEADERS.  Articles with no cached headers go in
+      ;; UNCACHED-ARTICLES to be fetched from the server.
       (when (file-exists-p file)
         (with-current-buffer gnus-agent-overview-buffer
           (erase-buffer)
           (let ((nnheader-file-coding-system
                  gnus-agent-file-coding-system))
-            (nnheader-insert-nov-file file (car articles)))))
-
-      (if (setq uncached-articles (gnus-agent-uncached-articles articles group
-                                                                t))
-          (progn
-            ;; Populate nntp-server-buffer with uncached headers
-            (set-buffer nntp-server-buffer)
-            (erase-buffer)
-            (cond ((not (eq 'nov (let (gnus-agent) ; Turn off agent
-                                   (gnus-retrieve-headers
-                                    uncached-articles group))))
-                   (nnvirtual-convert-headers))
-                  ((eq 'nntp (car gnus-current-select-method))
-                   ;; The author of gnus-get-newsgroup-headers-xover
-                   ;; reports that the XOVER command is commonly
-                   ;; unreliable. The problem is that recently
-                   ;; posted articles may not be entered into the
-                   ;; NOV database in time to respond to my XOVER
-                   ;; query.
-                   ;;
-                   ;; I'm going to use his assumption that the NOV
-                   ;; database is updated in order of ascending
-                   ;; article ID.  Therefore, a response containing
-                   ;; article ID N implies that all articles from 1
-                   ;; to N-1 are up-to-date.  Therefore, missing
-                   ;; articles in that range have expired.
-
-                   (set-buffer nntp-server-buffer)
-                   (let* ((fetched-articles (list nil))
-                          (tail-fetched-articles fetched-articles)
-                          (min (car articles))
-                          (max (car (last articles))))
-
-                     ;; Get the list of articles that were fetched
-                     (goto-char (point-min))
-                     (let ((pm (point-max))
-                           art)
-                       (while (< (point) pm)
-                         (when (setq art (gnus-agent-read-article-number))
-                           (gnus-agent-append-to-list tail-fetched-articles art))
-                         (forward-line 1)))
-
-                     ;; Clip this list to the headers that will
-                     ;; actually be returned
-                     (setq fetched-articles (gnus-list-range-intersection
-                                             (cdr fetched-articles)
-                                             (cons min max)))
-
-                     ;; Clip the uncached articles list to exclude
-                     ;; IDs after the last FETCHED header.  The
-                     ;; excluded IDs may be fetchable using HEAD.
-                     (if (car tail-fetched-articles)
-                         (setq uncached-articles
-                               (gnus-list-range-intersection
-                                uncached-articles
-                                (cons (car uncached-articles)
-                                      (car tail-fetched-articles)))))
-
-                     ;; Create the list of articles that were
-                     ;; "successfully" fetched.  Success, in this
-                     ;; case, means that the ID should not be
-                     ;; fetched again.  In the case of an expired
-                     ;; article, the header will not be fetched.
-                     (setq uncached-articles
-                           (gnus-sorted-nunion fetched-articles
-                                               uncached-articles))
-                     )))
-
-            ;; Erase the temp buffer
-            (set-buffer gnus-agent-overview-buffer)
-            (erase-buffer)
-
-            ;; Copy the nntp-server-buffer to the temp buffer
-            (set-buffer nntp-server-buffer)
-            (copy-to-buffer gnus-agent-overview-buffer (point-min) (point-max))
-
-            ;; Merge the temp buffer with the known headers (found on
-            ;; disk in FILE) into the nntp-server-buffer
-            (when uncached-articles
-              (gnus-agent-braid-nov uncached-articles file))
-
-            ;; Save the new set of known headers to FILE
-            (set-buffer nntp-server-buffer)
+            (nnheader-insert-nov-file file (car articles))
+            (with-current-buffer nntp-server-buffer
+              (erase-buffer)
+              (insert-buffer-substring gnus-agent-overview-buffer)
+              (setq headers
+                    (gnus-get-newsgroup-headers-xover
+                     articles nil (buffer-local-value
+                                   'gnus-newsgroup-dependencies
+                                   gnus-summary-buffer)
+                     gnus-newsgroup-name))))))
+
+      (setq uncached-articles
+            (gnus-agent-uncached-articles articles group t))
+
+      (when uncached-articles
+        (let ((gnus-newsgroup-name group)
+              gnus-agent)               ; Prevent loop.
+          ;; Fetch additional headers for the uncached articles.
+          (setq fetched-headers (gnus-fetch-headers uncached-articles))
+          ;; Merge headers we got from the overview file with our
+          ;; newly-fetched headers.
+          (when fetched-headers
+            (setq headers
+                  (delete-dups
+                   (sort (append headers (copy-sequence fetched-headers))
+                         (lambda (l r)
+                           (< (mail-header-number l)
+                              (mail-header-number r))))))
+
+            ;; Add the new set of known headers to the overview file.
             (let ((coding-system-for-write
                    gnus-agent-file-coding-system))
-              (gnus-agent-check-overview-buffer)
-              (write-region (point-min) (point-max) file nil 'silent))
-
-            (gnus-agent-update-view-total-fetched-for group t)
-
-            ;; Update the group's article alist to include the newly
-            ;; fetched articles.
-            (gnus-agent-load-alist group)
-            (gnus-agent-save-alist group uncached-articles nil)
-            )
-
-        ;; Copy the temp buffer to the nntp-server-buffer
-        (set-buffer nntp-server-buffer)
-        (erase-buffer)
-        (insert-buffer-substring gnus-agent-overview-buffer)))
-
-    (if (and fetch-old
-             (not (numberp fetch-old)))
-        t                               ; Don't remove anything.
-      (nnheader-nov-delete-outside-range
-       (car articles)
-       (car (last articles)))
-      t)
-
-    'nov))
+              (with-current-buffer gnus-agent-overview-buffer
+                ;; We stick the new headers in at the end, then
+                ;; re-sort the whole buffer with
+                ;; `sort-numeric-fields'.  If this turns out to be
+                ;; slow, we could consider a loop to add the headers
+                ;; in sorted order to begin with.
+                (goto-char (point-max))
+                (mapc #'nnheader-insert-nov fetched-headers)
+                (sort-numeric-fields 1 (point-min) (point-max))
+                (gnus-agent-check-overview-buffer)
+                (write-region (point-min) (point-max) file nil 'silent)
+                (gnus-agent-update-view-total-fetched-for group t)
+                ;; Update the group's article alist to include the
+                ;; newly fetched articles.
+                (gnus-agent-load-alist group)
+                (gnus-agent-save-alist group uncached-articles nil))))))
+      headers)))
 
 (defun gnus-agent-request-article (article group)
   "Retrieve ARTICLE in GROUP from the agent cache."
diff --git a/lisp/gnus/gnus-async.el b/lisp/gnus/gnus-async.el
index fefd02c7bfb..ed948a26c0b 100644
--- a/lisp/gnus/gnus-async.el
+++ b/lisp/gnus/gnus-async.el
@@ -357,8 +357,13 @@ that was fetched."
         (let ((nntp-server-buffer (current-buffer))
               (nnheader-callback-function
                (lambda (_arg)
-                  (setq gnus-async-header-prefetched
-                        (cons group unread)))))
+                 (setq gnus-async-header-prefetched
+                       (cons group unread)))))
+          ;; FIXME: If header prefetch is ever put into use, we'll
+          ;; have to handle the possibility that
+          ;; `gnus-retrieve-headers' might return a list of header
+          ;; vectors directly, rather than writing them into the
+          ;; current buffer.
           (gnus-retrieve-headers unread group gnus-fetch-old-headers))))))
 
 (defun gnus-async-retrieve-fetched-headers (articles group)
diff --git a/lisp/gnus/gnus-cache.el b/lisp/gnus/gnus-cache.el
index 36657e46219..9423d9f2f6b 100644
--- a/lisp/gnus/gnus-cache.el
+++ b/lisp/gnus/gnus-cache.el
@@ -294,49 +294,47 @@ it's not cached."
 (defun gnus-cache-retrieve-headers (articles group &optional fetch-old)
   "Retrieve the headers for ARTICLES in GROUP."
   (let ((cached
-         (setq gnus-newsgroup-cached (gnus-cache-articles-in-group group))))
+         (setq gnus-newsgroup-cached (gnus-cache-articles-in-group group)))
+        (gnus-newsgroup-name group)
+        (gnus-fetch-old-headers fetch-old))
     (if (not cached)
         ;; No cached articles here, so we just retrieve them
         ;; the normal way.
         (let ((gnus-use-cache nil))
-          (gnus-retrieve-headers articles group fetch-old))
+          (gnus-retrieve-headers articles group))
       (let ((uncached-articles (gnus-sorted-difference articles cached))
             (cache-file (gnus-cache-file-name group ".overview"))
-            type
-            (file-name-coding-system nnmail-pathname-coding-system))
+            (file-name-coding-system nnmail-pathname-coding-system)
+            headers)
         ;; We first retrieve all the headers that we don't have in
         ;; the cache.
         (let ((gnus-use-cache nil))
           (when uncached-articles
-            (setq type (and articles
-                            (gnus-retrieve-headers
-                             uncached-articles group fetch-old)))))
+            (setq headers (and articles
+                               (gnus-fetch-headers uncached-articles)))))
         (gnus-cache-save-buffers)
-        ;; Then we insert the cached headers.
-        (save-excursion
-          (cond
-           ((not (file-exists-p cache-file))
-            ;; There are no cached headers.
-            type)
-           ((null type)
-            ;; There were no uncached headers (or retrieval was
-            ;; unsuccessful), so we use the cached headers exclusively.
-            (set-buffer nntp-server-buffer)
-            (erase-buffer)
-            (let ((coding-system-for-read
-                   gnus-cache-overview-coding-system))
-              (insert-file-contents cache-file))
-            'nov)
-           ((eq type 'nov)
-            ;; We have both cached and uncached NOV headers, so we
-            ;; braid them.
-            (gnus-cache-braid-nov group cached)
-            type)
-           (t
-            ;; We braid HEADs.
-            (gnus-cache-braid-heads group (gnus-sorted-intersection
-                                           cached articles))
-            type)))))))
+        ;; Then we include the cached headers.
+        (when (file-exists-p cache-file)
+          (setq headers
+                (delete-dups
+                 (sort
+                  (append headers
+                          (let ((coding-system-for-read
+                                 gnus-cache-overview-coding-system))
+                            (with-current-buffer nntp-server-buffer
+                              (erase-buffer)
+                              (insert-file-contents cache-file)
+                              (gnus-get-newsgroup-headers-xover
+                               (gnus-sorted-difference
+                                cached uncached-articles)
+                               nil (buffer-local-value
+                                    'gnus-newsgroup-dependencies
+                                    gnus-summary-buffer)
+                               group))))
+                  (lambda (l r)
+                    (< (mail-header-number l)
+                       (mail-header-number r)))))))
+        headers))))
 
 (defun gnus-cache-enter-article (&optional n)
   "Enter the next N articles into the cache.
@@ -529,70 +527,6 @@ Returns the list of articles removed."
           (setq gnus-cache-active-altered t)))
       articles)))
 
-(defun gnus-cache-braid-nov (group cached &optional file)
-  (let ((cache-buf (gnus-get-buffer-create " *gnus-cache*"))
-        beg end)
-    (gnus-cache-save-buffers)
-    (with-current-buffer cache-buf
-      (erase-buffer)
-      (let ((coding-system-for-read gnus-cache-overview-coding-system)
-            (file-name-coding-system nnmail-pathname-coding-system))
-        (insert-file-contents
-         (or file (gnus-cache-file-name group ".overview"))))
-      (goto-char (point-min))
-      (insert "\n")
-      (goto-char (point-min)))
-    (set-buffer nntp-server-buffer)
-    (goto-char (point-min))
-    (while cached
-      (while (and (not (eobp))
-                  (< (read (current-buffer)) (car cached)))
-        (forward-line 1))
-      (beginning-of-line)
-      (set-buffer cache-buf)
-      (if (search-forward (concat "\n" (int-to-string (car cached)) "\t")
-                          nil t)
-          (setq beg (point-at-bol)
-                end (progn (end-of-line) (point)))
-        (setq beg nil))
-      (set-buffer nntp-server-buffer)
-      (when beg
-        (insert-buffer-substring cache-buf beg end)
-        (insert "\n"))
-      (setq cached (cdr cached)))
-    (kill-buffer cache-buf)))
-
-(defun gnus-cache-braid-heads (group cached)
-  (let ((cache-buf (gnus-get-buffer-create " *gnus-cache*")))
-    (with-current-buffer cache-buf
-      (erase-buffer))
-    (set-buffer nntp-server-buffer)
-    (goto-char (point-min))
-    (dolist (entry cached)
-      (while (and (not (eobp))
-                  (looking-at "2.. +\\([0-9]+\\) ")
-                  (< (progn (goto-char (match-beginning 1))
-                            (read (current-buffer)))
-                     entry))
-        (search-forward "\n.\n" nil 'move))
-      (beginning-of-line)
-      (set-buffer cache-buf)
-      (erase-buffer)
-      (let ((coding-system-for-read gnus-cache-coding-system)
-            (file-name-coding-system nnmail-pathname-coding-system))
-        (insert-file-contents (gnus-cache-file-name group entry)))
-      (goto-char (point-min))
-      (insert "220 ")
-      (princ (pop cached) (current-buffer))
-      (insert " Article retrieved.\n")
-      (search-forward "\n\n" nil 'move)
-      (delete-region (point) (point-max))
-      (forward-char -1)
-      (insert ".")
-      (set-buffer nntp-server-buffer)
-      (insert-buffer-substring cache-buf))
-    (kill-buffer cache-buf)))
-
 ;;;###autoload
 (defun gnus-jog-cache ()
   "Go through all groups and put the articles into the cache.
diff --git a/lisp/gnus/gnus-cloud.el b/lisp/gnus/gnus-cloud.el
index f7c71f43ce8..00b85f546c2 100644
--- a/lisp/gnus/gnus-cloud.el
+++ b/lisp/gnus/gnus-cloud.el
@@ -30,6 +30,8 @@
 
 (require 'parse-time)
 (require 'nnimap)
+(declare-function gnus-fetch-headers "gnus-sum")
+(defvar gnus-alter-header-function)
 
 (eval-when-compile (require 'epg)) ;; setf-method for `epg-context-armor'
 (autoload 'epg-make-context "epg")
@@ -391,8 +393,6 @@ When FULL is t, upload everything, not just a difference from the last full."
             (gnus-group-refresh-group group))
         (gnus-error 2 "Failed to upload Gnus Cloud data to %s" group)))))
 
-(defvar gnus-alter-header-function)
-
 (defun gnus-cloud-add-timestamps (elems)
   (dolist (elem elems)
     (let* ((file-name (plist-get elem :file-name))
@@ -407,14 +407,10 @@ When FULL is t, upload everything, not just a difference from the last full."
   (gnus-activate-group gnus-cloud-group-name nil nil gnus-cloud-method)
   (let* ((group (gnus-group-full-name gnus-cloud-group-name gnus-cloud-method))
          (active (gnus-active group))
-         headers head)
-    (when (gnus-retrieve-headers (gnus-uncompress-range active) group)
-      (with-current-buffer nntp-server-buffer
-        (goto-char (point-min))
-        (while (setq head (nnheader-parse-head))
-          (when gnus-alter-header-function
-            (funcall gnus-alter-header-function head))
-          (push head headers))))
+         (gnus-newsgroup-name group)
+         (headers (gnus-fetch-headers (gnus-uncompress-range active))))
+    (when gnus-alter-header-function
+      (mapc gnus-alter-header-function headers))
     (sort (nreverse headers)
           (lambda (h1 h2)
             (> (gnus-cloud-chunk-sequence (mail-header-subject h1))
diff --git a/lisp/gnus/gnus-search.el b/lisp/gnus/gnus-search.el
index 5c6a5b9efd0..44780609af7 100644
--- a/lisp/gnus/gnus-search.el
+++ b/lisp/gnus/gnus-search.el
@@ -909,6 +909,7 @@ quirks.")
 (defclass gnus-search-namazu (gnus-search-indexed)
   ((index-directory
     :initarg :index-directory
+    :initform (symbol-value 'gnus-search-namazu-index-directory)
     :type string
     :custom directory)
    (program
diff --git a/lisp/gnus/gnus-start.el b/lisp/gnus/gnus-start.el
index fbdbf41dc05..cf37a1ccdfc 100644
--- a/lisp/gnus/gnus-start.el
+++ b/lisp/gnus/gnus-start.el
@@ -637,7 +637,7 @@ the first newsgroup."
     ;; We subscribe the group by changing its level to `subscribed'.
     (gnus-group-change-level
      newsgroup gnus-level-default-subscribed
-     gnus-level-killed (or next "dummy.group"))
+     gnus-level-killed next)
     (gnus-request-update-group-status newsgroup 'subscribe)
     (gnus-message 5 "Subscribe newsgroup: %s" newsgroup)
     (run-hook-with-args 'gnus-subscribe-newsgroup-functions newsgroup)
@@ -1282,7 +1282,8 @@ string name) to insert this group before."
         (gnus-dribble-enter
          (format "(gnus-group-change-level %S %S %S %S %S)"
                  group level oldlevel
-                 (cadr (member previous gnus-group-list))
+                 (when previous
+                   (cadr (member previous gnus-group-list)))
                  fromkilled)))
 
       ;; Then we remove the newgroup from any old structures, if needed.
@@ -1341,9 +1342,10 @@ string name) to insert this group before."
           ;; at the head of `gnus-newsrc-alist'.
           (push info (cdr gnus-newsrc-alist))
           (puthash group (list num info) gnus-newsrc-hashtb)
-          (when (stringp previous)
+          (when (and previous (stringp previous))
             (setq previous (gnus-group-entry previous)))
-          (let ((idx (or (seq-position gnus-group-list (caadr previous))
+          (let ((idx (or (and previous
+                              (seq-position gnus-group-list (caadr previous)))
                          (length gnus-group-list))))
             (push group (nthcdr idx gnus-group-list)))
           (gnus-dribble-enter
diff --git a/lisp/gnus/gnus-sum.el b/lisp/gnus/gnus-sum.el
index b0f9ed4c6f0..5bd58b690af 100644
--- a/lisp/gnus/gnus-sum.el
+++ b/lisp/gnus/gnus-sum.el
@@ -5658,10 +5658,21 @@ or a straight list of headers."
           (setf (mail-header-subject header) subject))))))
 
 (defun gnus-fetch-headers (articles &optional limit force-new dependencies)
-  "Fetch headers of ARTICLES."
+  "Fetch headers of ARTICLES.
+This calls the `gnus-retrieve-headers' function of the current
+group's backend server.  The server can do one of two things:
+
+1. Write the headers for ARTICLES into the
+   `nntp-server-buffer' (the current buffer) in a parseable format, or
+2. Return the headers directly as a list of vectors.
+
+In the first case, `gnus-retrieve-headers' returns a symbol
+value, either `nov' or `headers'.  This value determines which
+parsing function is used to read the headers.  It is also stored
+into the variable `gnus-headers-retrieved-by', which is consulted
+later when possibly building full threads."
   (gnus-message 7 "Fetching headers for %s..." gnus-newsgroup-name)
-  (prog1
-      (pcase (setq gnus-headers-retrieved-by
+  (let ((res (setq gnus-headers-retrieved-by
                    (gnus-retrieve-headers
                     articles gnus-newsgroup-name
                     (or limit
@@ -5671,22 +5682,34 @@ or a straight list of headers."
                                   (not (eq gnus-fetch-old-headers 'some))
                                   (not (numberp gnus-fetch-old-headers)))
                                  (> (length articles) 1))
-                             gnus-fetch-old-headers))))
-    ('nov
-     (gnus-get-newsgroup-headers-xover
-      articles force-new dependencies gnus-newsgroup-name t))
-    ('headers
-     (gnus-get-newsgroup-headers dependencies force-new))
-    ((pred listp)
-     (let ((dependencies
-            (or dependencies
-                (with-current-buffer gnus-summary-buffer
-                  gnus-newsgroup-dependencies))))
-     (delq nil (mapcar   #'(lambda (header)
-                             (gnus-dependencies-add-header
-                              header dependencies force-new))
-                         gnus-headers-retrieved-by)))))
-  (gnus-message 7 "Fetching headers for %s...done" gnus-newsgroup-name)))
+                             gnus-fetch-old-headers))))))
+    (prog1
+        (pcase res
+          ('nov
+           (gnus-get-newsgroup-headers-xover
+            articles force-new dependencies gnus-newsgroup-name t))
+          ;; For now, assume that any backend returning its own
+          ;; headers takes some effort to do so, so return `headers'.
+          ((pred listp)
+           (setq gnus-headers-retrieved-by 'headers)
+           (let ((dependencies
+                  (or dependencies
+                      (buffer-local-value
+                       'gnus-newsgroup-dependencies gnus-summary-buffer))))
+             (when (functionp gnus-alter-header-function)
+               (mapc gnus-alter-header-function res))
+             (mapc (lambda (header)
+                     ;; The agent or the cache may have already
+                     ;; registered this header in the dependency
+                     ;; table.
+                     (unless (gethash (mail-header-id header) dependencies)
+                       (gnus-dependencies-add-header
+                        header dependencies force-new)))
+                   res)
+             res))
+          (_ (gnus-get-newsgroup-headers dependencies force-new)))
+      (gnus-message 7 "Fetching headers for %s...done"
+                    gnus-newsgroup-name))))
 
 (defun gnus-select-newsgroup (group &optional read-all select-articles)
   "Select newsgroup GROUP.
@@ -6443,6 +6466,10 @@ The resulting hash table is returned, or nil if no Xrefs were found."
         (unless (gnus-ephemeral-group-p group)
           (gnus-group-update-group group t))))))
 
+;; FIXME: Refactor this with `gnus-get-newsgroup-headers-xover' and
+;; extract the necessary bits for the direct-header-return case.  Also
+;; look at this and see how similar it is to
+;; `nnheader-parse-naked-head'.
 (defun gnus-get-newsgroup-headers (&optional dependencies force-new)
   (let ((dependencies
          (or dependencies
diff --git a/lisp/gnus/gnus.el b/lisp/gnus/gnus.el
index 91ab878b22f..4241f30ba9d 100644
--- a/lisp/gnus/gnus.el
+++ b/lisp/gnus/gnus.el
@@ -2388,7 +2388,14 @@ Typical marks are those that make no sense in a standalone back end,
 such as a mark that says whether an article is stored in the cache
 \(which doesn't make sense in a standalone back end).")
 
-(defvar gnus-headers-retrieved-by nil)
+(defvar gnus-headers-retrieved-by nil
+  "Holds the return value of `gnus-retrieve-headers'.
+This is either the symbol `nov' or the symbol `headers'.  This
+value is checked during the summary creation process, when
+building threads.  A value of `nov' indicates that header
+retrieval is relatively cheap and threading is encouraged to
+include more old articles.  A value of `headers' indicates that
+retrieval is expensive and should be minimized.")
 (defvar gnus-article-reply nil)
 (defvar gnus-override-method nil)
 (defvar gnus-opened-servers nil)
diff --git a/lisp/gnus/message.el b/lisp/gnus/message.el
index 50e02187484..1409a4384ab 100644
--- a/lisp/gnus/message.el
+++ b/lisp/gnus/message.el
@@ -47,7 +47,7 @@
 (require 'rfc2047)
 (require 'puny)
 (require 'rmc)                          ; read-multiple-choice
-(eval-when-compile (require 'subr-x))
+(require 'subr-x)
 
 (autoload 'mailclient-send-it "mailclient")
 
@@ -620,8 +620,8 @@ Done before generating the new subject of a forward."
 
 (defcustom message-forward-ignored-headers "^Content-Transfer-Encoding:\\|^X-Gnus"
   "All headers that match this regexp will be deleted when forwarding a message.
-This variable is not consulted when forwarding encrypted messages
-and `message-forward-show-mml' is `best'.
+Also see `message-forward-included-headers' -- both variables are applied.
+In addition, see `message-forward-included-mime-headers'.
 
 This may also be a list of regexps."
   :version "21.1"
@@ -637,7 +637,14 @@ This may also be a list of regexps."
   '("^From:" "^Subject:" "^Date:" "^To:" "^Cc:")
   "If non-nil, delete non-matching headers when forwarding a message.
 Only headers that match this regexp will be included.  This
-variable should be a regexp or a list of regexps."
+variable should be a regexp or a list of regexps.
+
+Also see `message-forward-ignored-headers' -- both variables are applied.
+In addition, see `message-forward-included-mime-headers'.
+
+When forwarding messages as MIME, but when
+`message-forward-show-mml' results in MML not being used,
+`message-forward-included-mime-headers' take precedence."
   :version "27.1"
   :group 'message-forwarding
   :type '(repeat :value-to-internal (lambda (widget value)
@@ -647,6 +654,24 @@ variable should be a regexp or a list of regexps."
                               (widget-editable-list-match widget value)))
                  regexp))
 
+(defcustom message-forward-included-mime-headers
+  '("^Content-Type:" "^MIME-Version:")
+  "When forwarding as MIME, but not using MML, don't delete these headers.
+Also see `message-forward-ignored-headers' and
+`message-forward-ignored-headers'.
+
+When forwarding messages as MIME, but when
+`message-forward-show-mml' results in MML not being used,
+`message-forward-included-mime-headers' take precedence."
+  :version "28.1"
+  :group 'message-forwarding
+  :type '(repeat :value-to-internal (lambda (widget value)
+                                      (custom-split-regexp-maybe value))
+                 :match (lambda (widget value)
+                          (or (stringp value)
+                              (widget-editable-list-match widget value)))
+                 regexp))
+
 (defcustom message-ignored-cited-headers "."
   "Delete these headers from the messages you yank."
   :group 'message-insertion
@@ -3057,22 +3082,23 @@ See also `message-forbidden-properties'."
 
 (defun message--syntax-propertize (beg end)
   "Syntax-propertize certain message text specially."
-  (let ((citation-regexp (concat "^" message-cite-prefix-regexp ".*$"))
-        (smiley-regexp (regexp-opt message-smileys)))
-    (goto-char beg)
-    (while (search-forward-regexp citation-regexp
-                                  end 'noerror)
-      (let ((start (match-beginning 0))
-            (end (match-end 0)))
-        (add-text-properties start (1+ start)
-                             `(syntax-table ,(string-to-syntax "<")))
-        (add-text-properties end (min (1+ end) (point-max))
-                             `(syntax-table ,(string-to-syntax ">")))))
-    (goto-char beg)
-    (while (search-forward-regexp smiley-regexp
-            end 'noerror)
-      (add-text-properties (match-beginning 0) (match-end 0)
-                           `(syntax-table ,(string-to-syntax "."))))))
+  (with-syntax-table message-mode-syntax-table
+    (let ((citation-regexp (concat "^" message-cite-prefix-regexp ".*$"))
+          (smiley-regexp (regexp-opt message-smileys)))
+      (goto-char beg)
+      (while (search-forward-regexp citation-regexp
+                                    end 'noerror)
+        (let ((start (match-beginning 0))
+              (end (match-end 0)))
+          (add-text-properties start (1+ start)
+                               `(syntax-table ,(string-to-syntax "<")))
+          (add-text-properties end (min (1+ end) (point-max))
+                               `(syntax-table ,(string-to-syntax ">")))))
+      (goto-char beg)
+      (while (search-forward-regexp smiley-regexp
+                                    end 'noerror)
+        (add-text-properties (match-beginning 0) (match-end 0)
+                             `(syntax-table ,(string-to-syntax ".")))))))
 
 ;;;###autoload
 (define-derived-mode message-mode text-mode "Message"
@@ -7616,14 +7642,28 @@ Optional DIGEST will use digest to forward."
      "-------------------- End of forwarded message --------------------\n")
     (message-remove-ignored-headers b e)))
 
-(defun message-remove-ignored-headers (b e)
+(defun message-remove-ignored-headers (b e &optional preserve-mime)
   (when (or message-forward-ignored-headers
             message-forward-included-headers)
+    (let ((saved-headers nil))
     (save-restriction
       (narrow-to-region b e)
       (goto-char b)
       (narrow-to-region (point)
                         (or (search-forward "\n\n" nil t) (point)))
+      ;; When forwarding as MIME, preserve some MIME headers.
+      (when preserve-mime
+        (let ((headers (buffer-string)))
+          (with-temp-buffer
+            (insert headers)
+            (message-remove-header
+             (if (listp message-forward-included-mime-headers)
+                 (mapconcat
+                  #'identity (cons "^$" message-forward-included-mime-headers)
+                  "\\|")
+               message-forward-included-mime-headers)
+             t nil t)
+            (setq saved-headers (string-lines (buffer-string) t)))))
       (when message-forward-ignored-headers
         (let ((ignored (if (stringp message-forward-ignored-headers)
                            (list message-forward-ignored-headers)
@@ -7636,10 +7676,14 @@ Optional DIGEST will use digest to forward."
              (mapconcat #'identity (cons "^$" message-forward-included-headers)
                         "\\|")
            message-forward-included-headers)
-         t nil t)))))
+         t nil t))
+      ;; Insert the MIME headers, if any.
+      (goto-char (point-max))
+      (forward-line -1)
+      (dolist (header saved-headers)
+        (insert header "\n"))))))
 
-(defun message-forward-make-body-mime (forward-buffer &optional beg end
-                                                      remove-headers)
+(defun message-forward-make-body-mime (forward-buffer &optional beg end)
   (let ((b (point)))
     (insert "\n\n<#part type=message/rfc822 disposition=inline raw=t>\n")
     (save-restriction
@@ -7649,8 +7693,7 @@ Optional DIGEST will use digest to forward."
       (goto-char (point-min))
       (when (looking-at "From ")
         (replace-match "X-From-Line: "))
-      (when remove-headers
-        (message-remove-ignored-headers (point-min) (point-max)))
+      (message-remove-ignored-headers (point-min) (point-max) t)
       (goto-char (point-max)))
     (insert "<#/part>\n")
     ;; Consider there is no illegible text.
@@ -7789,8 +7832,7 @@ is for the internal use."
                                  (message-signed-or-encrypted-p)
                                (error t))))))
             (message-forward-make-body-mml forward-buffer)
-          (message-forward-make-body-mime
-           forward-buffer nil nil (not (eq message-forward-show-mml 'best))))
+          (message-forward-make-body-mime forward-buffer))
       (message-forward-make-body-plain forward-buffer)))
   (message-position-point))
 
diff --git a/lisp/gnus/nnml.el b/lisp/gnus/nnml.el
index ebececa3ce2..3cdfc749703 100644
--- a/lisp/gnus/nnml.el
+++ b/lisp/gnus/nnml.el
@@ -769,8 +769,24 @@ article number.  This function is called narrowed to an article."
       (let ((headers (nnheader-parse-head t)))
         (setf (mail-header-chars  headers) chars)
         (setf (mail-header-number headers) number)
+        ;; If there's non-ASCII raw characters in the data,
+        ;; RFC2047-encode them to avoid having arbitrary data in the
+        ;; .overview file.
+        (nnml--encode-headers headers)
         headers))))
 
+(defun nnml--encode-headers (headers)
+  (let ((subject (mail-header-subject headers))
+        (rfc2047-encoding-type 'mime))
+    (unless (string-match "\\`[[:ascii:]]*\\'" subject)
+      (setf (mail-header-subject headers)
+            (mail-encode-encoded-word-string subject t))))
+  (let ((from (mail-header-from headers))
+        (rfc2047-encoding-type 'address-mime))
+    (unless (string-match "\\`[[:ascii:]]*\\'" from)
+      (setf (mail-header-from headers)
+            (rfc2047-encode-string from t)))))
+
 (defun nnml-get-nov-buffer (group &optional incrementalp)
   (let ((buffer (gnus-get-buffer-create
                  (format " *nnml %soverview %s*"
diff --git a/lisp/gnus/nntp.el b/lisp/gnus/nntp.el
index 7e10e151a4d..c2bb960f945 100644
--- a/lisp/gnus/nntp.el
+++ b/lisp/gnus/nntp.el
@@ -1209,7 +1209,7 @@ If SEND-IF-FORCE, only send authinfo to the server if the
                           (read-passwd (format "NNTP (%s@%s) password: "
                                                user nntp-address)))))))
           (if (not result)
-              (signal 'nntp-authinfo-rejected "Password rejected")
+              (error "Password rejected")
             result))))))
 
 ;;; Internal functions.
diff --git a/lisp/gnus/nnvirtual.el b/lisp/gnus/nnvirtual.el
index 1e2feda6365..ba2934351d6 100644
--- a/lisp/gnus/nnvirtual.el
+++ b/lisp/gnus/nnvirtual.el
@@ -101,15 +101,10 @@ It is computed from the marks of individual component groups.")
       (erase-buffer)
       (if (stringp (car articles))
           'headers
-        (let ((vbuf (nnheader-set-temp-buffer
-                     (gnus-get-buffer-create " *virtual headers*")))
-              (carticles (nnvirtual-partition-sequence articles))
+        (let ((carticles (nnvirtual-partition-sequence articles))
               (sysname (system-name))
-              cgroup carticle article result prefix)
-          (while carticles
-            (setq cgroup (caar carticles))
-            (setq articles (cdar carticles))
-            (pop carticles)
+              cgroup headers all-headers article prefix)
+          (pcase-dolist (`(,cgroup . ,articles) carticles)
             (when (and articles
                        (gnus-check-server
                         (gnus-find-method-for-group cgroup) t)
@@ -119,69 +114,37 @@ It is computed from the marks of individual component groups.")
                        ;; This is probably evil if people have set
                        ;; gnus-use-cache to nil themselves, but I
                        ;; have no way of finding the true value of it.
-                       (let ((gnus-use-cache t))
-                         (setq result (gnus-retrieve-headers
-                                       articles cgroup nil))))
-              (set-buffer nntp-server-buffer)
-              ;; If we got HEAD headers, we convert them into NOV
-              ;; headers.  This is slow, inefficient and, come to think
-              ;; of it, downright evil.  So sue me.  I couldn't be
-              ;; bothered to write a header parse routine that could
-              ;; parse a mixed HEAD/NOV buffer.
-              (when (eq result 'headers)
-                (nnvirtual-convert-headers))
-              (goto-char (point-min))
-              (while (not (eobp))
-                (delete-region (point)
-                               (progn
-                                 (setq carticle (read nntp-server-buffer))
-                                 (point)))
-
-                ;; We remove this article from the articles list, if
-                ;; anything is left in the articles list after going through
-                ;; the entire buffer, then those articles have been
-                ;; expired or canceled, so we appropriately update the
-                ;; component group below.  They should be coming up
-                ;; generally in order, so this shouldn't be slow.
-                (setq articles (delq carticle articles))
-
-                (setq article (nnvirtual-reverse-map-article cgroup carticle))
-                (if (null article)
-                    ;; This line has no reverse mapping, that means it
-                    ;; was an extra article reference returned by nntp.
-                    (progn
-                      (beginning-of-line)
-                      (delete-region (point) (progn (forward-line 1) (point))))
-                  ;; Otherwise insert the virtual article number,
-                  ;; and clean up the xrefs.
-                  (princ article nntp-server-buffer)
-                  (nnvirtual-update-xref-header cgroup carticle
-                                                prefix sysname)
-                  (forward-line 1))
-                )
-
-              (set-buffer vbuf)
-              (goto-char (point-max))
-              (insert-buffer-substring nntp-server-buffer))
-            ;; Anything left in articles is expired or canceled.
-            ;; Could be smart and not tell it about articles already known?
-            (when articles
-              (gnus-group-make-articles-read cgroup articles))
-            )
-
-          ;; The headers are ready for reading, so they are inserted into
-          ;; the nntp-server-buffer, which is where Gnus expects to find
-          ;; them.
-          (prog1
-              (with-current-buffer nntp-server-buffer
-                (erase-buffer)
-                (insert-buffer-substring vbuf)
-                ;; FIX FIX FIX, we should be able to sort faster than
-                ;; this if needed, since each cgroup is sorted, we just
-                ;; need to merge
-                (sort-numeric-fields 1 (point-min) (point-max))
-                'nov)
-            (kill-buffer vbuf)))))))
+                       (let ((gnus-use-cache t)
+                             (gnus-newsgroup-name cgroup)
+                             (gnus-fetch-old-headers nil))
+                         (setq headers (gnus-fetch-headers articles))))
+              (erase-buffer)
+              ;; Remove all header article numbers from `articles'.
+              ;; If there's anything left, those are expired or
+              ;; canceled articles, so we update the component group
+              ;; below.
+              (dolist (h headers)
+                (setq articles (delq (mail-header-number h) articles)
+                      article (nnvirtual-reverse-map-article
+                               cgroup (mail-header-number h)))
+                ;; Update all the header numbers according to their
+                ;; reverse mapping, and drop any with no such mapping.
+                (when article
+                  ;; Do this first, before we re-set the header's
+                  ;; article number.
+                  (nnvirtual-update-xref-header
+                   h cgroup prefix sysname)
+                  (setf (mail-header-number h) article)
+                  (push h all-headers)))
+              ;; Anything left in articles is expired or canceled.
+              ;; Could be smart and not tell it about articles already
+              ;; known?
+              (when articles
+                (gnus-group-make-articles-read cgroup articles))))
+
+          (sort all-headers (lambda (h1 h2)
+                              (< (mail-header-number h1)
+                                 (mail-header-number h2)))))))))
 
 
 (defvoo nnvirtual-last-accessed-component-group nil)
@@ -372,61 +335,18 @@ It is computed from the marks of individual component groups.")
 
 ;;; Internal functions.
 
-(defun nnvirtual-convert-headers ()
-  "Convert HEAD headers into NOV headers."
-  (with-current-buffer nntp-server-buffer
-    (let* ((dependencies (make-hash-table :test #'equal))
-           (headers (gnus-get-newsgroup-headers dependencies)))
-      (erase-buffer)
-      (mapc 'nnheader-insert-nov headers))))
-
-
-(defun nnvirtual-update-xref-header (group article prefix sysname)
-  "Edit current NOV header in current buffer to have an xref to the component group, and also server prefix any existing xref lines."
-  ;; Move to beginning of Xref field, creating a slot if needed.
-  (beginning-of-line)
-  (looking-at
-   "[^\t]*\t[^\t]*\t[^\t]*\t[^\t]*\t[^\t]*\t[^\t]*\t[^\t]*\t")
-  (goto-char (match-end 0))
-  (unless (search-forward "\t" (point-at-eol) 'move)
-    (insert "\t"))
-
-  ;; Remove any spaces at the beginning of the Xref field.
-  (while (eq (char-after (1- (point))) ? )
-    (forward-char -1)
-    (delete-char 1))
-
-  (insert "Xref: " sysname " " group ":")
-  (princ article (current-buffer))
-  (insert " ")
-
-  ;; If there were existing xref lines, clean them up to have the correct
-  ;; component server prefix.
-  (save-restriction
-    (narrow-to-region (point)
-                      (or (search-forward "\t" (point-at-eol) t)
-                          (point-at-eol)))
-    (goto-char (point-min))
-    (when (re-search-forward "Xref: *[^\n:0-9 ]+ *" nil t)
-      (replace-match "" t t))
-    (goto-char (point-min))
-    (when (re-search-forward
-           (concat (regexp-quote (gnus-group-real-name group)) ":[0-9]+")
-           nil t)
-      (replace-match "" t t))
-    (unless (eobp)
-      (insert " ")
-      (when (not (string= "" prefix))
-        (while (re-search-forward "[^ ]+:[0-9]+" nil t)
-          (save-excursion
-            (goto-char (match-beginning 0))
-            (insert prefix))))))
-
-  ;; Ensure a trailing \t.
-  (end-of-line)
-  (or (eq (char-after (1- (point))) ?\t)
-      (insert ?\t)))
-
+(defun nnvirtual-update-xref-header (header group prefix sysname)
+  "Add xref to component GROUP to HEADER.
+Also add a server PREFIX any existing xref lines."
+  (let ((bits (split-string (mail-header-xref header)
+                            nil t "[[:blank:]]"))
+        (art-no (mail-header-number header)))
+    (setf (mail-header-xref header)
+          (concat
+           (format "%s %s:%d " sysname group art-no)
+           (mapconcat (lambda (bit)
+                        (concat prefix bit))
+                      bits " ")))))
 
 (defun nnvirtual-possibly-change-server (server)
   (or (not server)
diff --git a/lisp/help-fns.el b/lisp/help-fns.el
index 8ce936ad164..879653057d0 100644
--- a/lisp/help-fns.el
+++ b/lisp/help-fns.el
@@ -1655,6 +1655,9 @@ in `describe-keymap'.  See also `Searching the Active Keymaps'."
                              (get-char-property (point) 'local-map)
                            (current-local-map)))))
 
+(defvar keymap-name-history nil
+  "History for input to `describe-keymap'.")
+
 ;;;###autoload
 (defun describe-keymap (keymap)
   "Describe key bindings in KEYMAP.
diff --git a/lisp/hl-line.el b/lisp/hl-line.el
index 73870f9579e..82952e934b6 100644
--- a/lisp/hl-line.el
+++ b/lisp/hl-line.el
@@ -45,11 +45,7 @@
 ;; An overlay is used.  In the non-sticky cases, this overlay is
 ;; active only on the selected window.  A hook is added to
 ;; `post-command-hook' to activate the overlay and move it to the line
-;; about point.  To get the non-sticky behavior, `hl-line-unhighlight'
-;; is added to `pre-command-hook' as well.  This function deactivates
-;; the overlay unconditionally in case the command changes the
-;; selected window.  (It does so rather than keeping track of changes
-;; in the selected window).
+;; about point.
 
 ;; You could make variable `global-hl-line-mode' buffer-local and set
 ;; it to nil to avoid highlighting specific buffers, when the global
@@ -91,9 +87,9 @@ when `global-hl-line-sticky-flag' is non-nil.")
          (set symbol value)
          (dolist (buffer (buffer-list))
            (with-current-buffer buffer
-             (when hl-line-overlay
+             (when (overlayp hl-line-overlay)
                (overlay-put hl-line-overlay 'face hl-line-face))))
-         (when global-hl-line-overlay
+         (when (overlayp global-hl-line-overlay)
            (overlay-put global-hl-line-overlay 'face hl-line-face))))
 
 (defcustom hl-line-sticky-flag t
@@ -141,9 +137,7 @@ non-selected window.  Hl-Line mode uses the function
 `hl-line-highlight' on `post-command-hook' in this case.
 
 When `hl-line-sticky-flag' is nil, Hl-Line mode highlights the
-line about point in the selected window only.  In this case, it
-uses the function `hl-line-maybe-unhighlight' in
-addition to `hl-line-highlight' on `post-command-hook'."
+line about point in the selected window only."
   :group 'hl-line
   (if hl-line-mode
       (progn
@@ -151,12 +145,10 @@ addition to `hl-line-highlight' on `post-command-hook'."
         (add-hook 'change-major-mode-hook #'hl-line-unhighlight nil t)
         (hl-line-highlight)
         (setq hl-line-overlay-buffer (current-buffer))
-        (add-hook 'post-command-hook #'hl-line-highlight nil t)
-        (add-hook 'post-command-hook #'hl-line-maybe-unhighlight nil t))
+        (add-hook 'post-command-hook #'hl-line-highlight nil t))
     (remove-hook 'post-command-hook #'hl-line-highlight t)
     (hl-line-unhighlight)
-    (remove-hook 'change-major-mode-hook #'hl-line-unhighlight t)
-    (remove-hook 'post-command-hook #'hl-line-maybe-unhighlight t)))
+    (remove-hook 'change-major-mode-hook #'hl-line-unhighlight t)))
 
 (defun hl-line-make-overlay ()
   (let ((ol (make-overlay (point) (point))))
@@ -168,17 +160,19 @@ addition to `hl-line-highlight' on `post-command-hook'."
   "Activate the Hl-Line overlay on the current line."
   (if hl-line-mode      ; Might be changed outside the mode function.
       (progn
-        (unless hl-line-overlay
+        (unless (overlayp hl-line-overlay)
           (setq hl-line-overlay (hl-line-make-overlay))) ; To be moved.
         (overlay-put hl-line-overlay
                      'window (unless hl-line-sticky-flag (selected-window)))
-        (hl-line-move hl-line-overlay))
+        (hl-line-move hl-line-overlay)
+        (hl-line-maybe-unhighlight))
     (hl-line-unhighlight)))
 
 (defun hl-line-unhighlight ()
   "Deactivate the Hl-Line overlay on the current line."
-  (when hl-line-overlay
-    (delete-overlay hl-line-overlay)))
+  (when (overlayp hl-line-overlay)
+    (delete-overlay hl-line-overlay)
+    (setq hl-line-overlay nil)))
 
 (defun hl-line-maybe-unhighlight ()
   "Maybe deactivate the Hl-Line overlay on the current line.
@@ -191,8 +185,7 @@ such overlays in all buffers except the current one."
                (not (eq curbuf hlob))
                (not (minibufferp)))
       (with-current-buffer hlob
-        (when (overlayp hl-line-overlay)
-          (delete-overlay hl-line-overlay))))
+        (hl-line-unhighlight)))
     (when (and (overlayp hl-line-overlay)
                (eq (overlay-buffer hl-line-overlay) curbuf))
       (setq hl-line-overlay-buffer curbuf))))
@@ -205,8 +198,8 @@ If `global-hl-line-sticky-flag' is non-nil, Global Hl-Line mode
 highlights the line about the current buffer's point in all live
 windows.
 
-Global-Hl-Line mode uses the functions `global-hl-line-highlight'
-and `global-hl-line-maybe-unhighlight' on `post-command-hook'."
+Global-Hl-Line mode uses the function `global-hl-line-highlight'
+on `post-command-hook'."
   :global t
   :group 'hl-line
   (if global-hl-line-mode
@@ -214,25 +207,24 @@ and `global-hl-line-maybe-unhighlight' on `post-command-hook'."
         ;; In case `kill-all-local-variables' is called.
         (add-hook 'change-major-mode-hook #'global-hl-line-unhighlight)
         (global-hl-line-highlight-all)
-        (add-hook 'post-command-hook #'global-hl-line-highlight)
-        (add-hook 'post-command-hook #'global-hl-line-maybe-unhighlight))
+        (add-hook 'post-command-hook #'global-hl-line-highlight))
     (global-hl-line-unhighlight-all)
     (remove-hook 'post-command-hook #'global-hl-line-highlight)
-    (remove-hook 'change-major-mode-hook #'global-hl-line-unhighlight)
-    (remove-hook 'post-command-hook #'global-hl-line-maybe-unhighlight)))
+    (remove-hook 'change-major-mode-hook #'global-hl-line-unhighlight)))
 
 (defun global-hl-line-highlight ()
   "Highlight the current line in the current window."
   (when global-hl-line-mode     ; Might be changed outside the mode function.
     (unless (window-minibuffer-p)
-      (unless global-hl-line-overlay
+      (unless (overlayp global-hl-line-overlay)
         (setq global-hl-line-overlay (hl-line-make-overlay))) ; To be moved.
       (unless (member global-hl-line-overlay global-hl-line-overlays)
         (push global-hl-line-overlay global-hl-line-overlays))
       (overlay-put global-hl-line-overlay 'window
                    (unless global-hl-line-sticky-flag
                      (selected-window)))
-      (hl-line-move global-hl-line-overlay))))
+      (hl-line-move global-hl-line-overlay)
+      (global-hl-line-maybe-unhighlight))))
 
 (defun global-hl-line-highlight-all ()
   "Highlight the current line in all live windows."
@@ -243,8 +235,9 @@ and `global-hl-line-maybe-unhighlight' on `post-command-hook'."
 
 (defun global-hl-line-unhighlight ()
   "Deactivate the Global-Hl-Line overlay on the current line."
-  (when global-hl-line-overlay
-    (delete-overlay global-hl-line-overlay)))
+  (when (overlayp global-hl-line-overlay)
+    (delete-overlay global-hl-line-overlay)
+    (setq global-hl-line-overlay nil)))
 
 (defun global-hl-line-maybe-unhighlight ()
   "Maybe deactivate the Global-Hl-Line overlay on the current line.
@@ -256,9 +249,8 @@ all such overlays in all buffers except the current one."
                        (bufferp ovb)
                        (not (eq ovb (current-buffer)))
                        (not (minibufferp)))
-                (with-current-buffer ovb
-                  (when (overlayp global-hl-line-overlay)
-                    (delete-overlay global-hl-line-overlay))))))
+              (with-current-buffer ovb
+                (global-hl-line-unhighlight)))))
         global-hl-line-overlays))
 
 (defun global-hl-line-unhighlight-all ()
diff --git a/lisp/ibuf-ext.el b/lisp/ibuf-ext.el
index 7be1b3d16c9..44574abd46a 100644
--- a/lisp/ibuf-ext.el
+++ b/lisp/ibuf-ext.el
@@ -1497,10 +1497,10 @@ Ordering is lexicographic."
   (string-lessp
    ;; FIXME: For now just compare the file name and the process name
    ;; (if it exists).  Is there a better way to do this?
-   (or (buffer-file-name (car a))
+   (or (with-current-buffer (car a) (ibuffer-buffer-file-name))
        (let ((pr-a (get-buffer-process (car a))))
          (and (processp pr-a) (process-name pr-a))))
-   (or (buffer-file-name (car b))
+   (or (with-current-buffer (car b) (ibuffer-buffer-file-name))
        (let ((pr-b (get-buffer-process (car b))))
          (and (processp pr-b) (process-name pr-b))))))
 
@@ -1823,18 +1823,12 @@ When BUF nil, default to the buffer at current line."
 ;;;###autoload
 (defun ibuffer-mark-by-file-name-regexp (regexp)
   "Mark all buffers whose file name matches REGEXP."
-  (interactive "sMark by file name (regexp): ")
+  (interactive (list (read-regexp "Mark by file name (regexp)")))
   (ibuffer-mark-on-buffer
-   #'(lambda (buf)
-       (let ((name (or (buffer-file-name buf)
-                       (with-current-buffer buf
-                         (and
-                          (boundp 'dired-directory)
-                          (stringp dired-directory)
-                          dired-directory)))))
-         (when name
-           ;; Match on the displayed file name (which is abbreviated).
-           (string-match regexp (abbreviate-file-name name)))))))
+   (lambda (buf)
+     (when-let ((name (with-current-buffer buf (ibuffer-buffer-file-name))))
+       ;; Match on the displayed file name (which is abbreviated).
+       (string-match-p regexp (ibuffer--abbreviate-file-name name))))))
 
 ;;;###autoload
 (defun ibuffer-mark-by-content-regexp (regexp &optional all-buffers)
diff --git a/lisp/ibuffer.el b/lisp/ibuffer.el
index 4800e0243d7..84c53b16acf 100644
--- a/lisp/ibuffer.el
+++ b/lisp/ibuffer.el
@@ -1308,6 +1308,11 @@ a new window in the current frame, splitting vertically."
                           (car dired-directory)))))
         (and dirname (expand-file-name dirname))))))
 
+(defun ibuffer--abbreviate-file-name (filename)
+  "Abbreviate FILENAME using `ibuffer-directory-abbrev-alist'."
+  (let ((directory-abbrev-alist ibuffer-directory-abbrev-alist))
+    (abbreviate-file-name filename)))
+
 (define-ibuffer-op ibuffer-do-save ()
   "Save marked buffers as with `save-buffer'."
   (:complex t
@@ -1885,9 +1890,7 @@ If point is on a group name, this function operates on that group."
        (cond ((zerop total) "No files")
              ((= 1 total) "1 file")
              (t (format "%d files" total))))))
-  (let ((directory-abbrev-alist ibuffer-directory-abbrev-alist))
-    (abbreviate-file-name
-     (or (ibuffer-buffer-file-name) ""))))
+  (ibuffer--abbreviate-file-name (or (ibuffer-buffer-file-name) "")))
 
 (define-ibuffer-column filename-and-process
   (:name "Filename/Process"
diff --git a/lisp/image.el b/lisp/image.el
index 814035594b6..6955a90de77 100644
--- a/lisp/image.el
+++ b/lisp/image.el
@@ -264,9 +264,9 @@ compatibility with versions of Emacs that lack the variable
 ;; Used to be in image-type-header-regexps, but now not used anywhere
 ;; (since 2009-08-28).
 (defun image-jpeg-p (data)
-  (declare (obsolete "It is unused inside Emacs and will be removed." "27.1"))
   "Value is non-nil if DATA, a string, consists of JFIF image data.
 We accept the tag Exif because that is the same format."
+  (declare (obsolete "It is unused inside Emacs and will be removed." "27.1"))
   (setq data (ignore-errors (string-to-unibyte data)))
   (when (and data (string-match-p "\\`\xff\xd8" data))
     (catch 'jfif
diff --git a/lisp/international/fontset.el b/lisp/international/fontset.el
index 14e7b89dd1f..8f0f263dcce 100644
--- a/lisp/international/fontset.el
+++ b/lisp/international/fontset.el
@@ -719,6 +719,7 @@
                     georgian
                     cherokee
                     canadian-aboriginal
+                    cham
                     ogham
                     runic
                     symbol
diff --git a/lisp/isearch.el b/lisp/isearch.el
index c6f7fe7bd4a..a86678572c4 100644
--- a/lisp/isearch.el
+++ b/lisp/isearch.el
@@ -3757,23 +3757,27 @@ since they have special meaning in a regexp."
         (overlay-put isearch-overlay 'priority 1001)
         (overlay-put isearch-overlay 'face isearch-face)))
 
-  (when (and search-highlight-submatches
-             isearch-regexp)
+  (when (and search-highlight-submatches isearch-regexp)
     (mapc 'delete-overlay isearch-submatches-overlays)
     (setq isearch-submatches-overlays nil)
-    (let ((submatch-data (cddr (butlast match-data)))
+    ;; 'cddr' removes whole expression match from match-data
+    (let ((submatch-data (cddr match-data))
           (group 0)
-          ov face)
+          b e ov face)
       (while submatch-data
-        (setq group (1+ group))
-        (setq ov (make-overlay (pop submatch-data) (pop submatch-data))
-              face (intern-soft (format "isearch-group-%d" group)))
-        ;; Recycle faces from beginning.
-        (unless (facep face)
-          (setq group 1 face 'isearch-group-1))
-        (overlay-put ov 'face face)
-        (overlay-put ov 'priority 1002)
-        (push ov isearch-submatches-overlays)))))
+        (setq b (pop submatch-data)
+              e (pop submatch-data))
+        (when (and (integer-or-marker-p b)
+                   (integer-or-marker-p e))
+          (setq ov (make-overlay b e)
+                group (1+ group)
+                face (intern-soft (format "isearch-group-%d" group)))
+          ;; Recycle faces from beginning
+          (unless (facep face)
+            (setq group 1 face 'isearch-group-1))
+          (overlay-put ov 'face face)
+          (overlay-put ov 'priority 1002)
+          (push ov isearch-submatches-overlays))))))
 
 (defun isearch-dehighlight ()
   (when isearch-overlay
diff --git a/lisp/language/cham.el b/lisp/language/cham.el
index eef6d6f8f9f..089988da918 100644
--- a/lisp/language/cham.el
+++ b/lisp/language/cham.el
@@ -34,6 +34,12 @@
 (set-language-info-alist
  "Cham" '((charset unicode)
               (coding-system utf-8)
-              (coding-priority utf-8)))
+              (coding-priority utf-8)
+              (input-method . "cham")
+              (sample-text . "Cham (ꨌꩌ)\tꨦꨤꩌ ꨦꨁꨰ")
+              (documentation . "\
+The Cham script is a Brahmic script used to write Cham,
+an Austronesian language spoken by some 245,000 Chams
+in Vietnam and Cambodia.")))
 
 (provide 'cham)
diff --git a/lisp/leim/quail/cham.el b/lisp/leim/quail/cham.el
new file mode 100644
index 00000000000..d12ae6cddf0
--- /dev/null
+++ b/lisp/leim/quail/cham.el
@@ -0,0 +1,116 @@
+;;; cham.el --- Quail package for inputting Cham characters  -*- coding: utf-8; lexical-binding:t -*-
+
+;; Copyright (C) 2021 Free Software Foundation, Inc.
+
+;; Author: Eli Zaretskii <eliz@gnu.org>
+;; Keywords: i18n
+
+;; This file is part of GNU Emacs.
+
+;; GNU Emacs is free software: you can redistribute it and/or modify
+;; it under the terms of the GNU General Public License as published by
+;; the Free Software Foundation, either version 3 of the License, or
+;; (at your option) any later version.
+
+;; GNU Emacs is distributed in the hope that it will be useful,
+;; but WITHOUT ANY WARRANTY; without even the implied warranty of
+;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+;; GNU General Public License for more details.
+
+;; You should have received a copy of the GNU General Public License
+;; along with GNU Emacs.  If not, see <https://www.gnu.org/licenses/>.
+
+;;; Commentary:
+
+;; This file defines the following Cham keyboards:
+;;
+;; - QWERTY-based Cham.
+
+;;; Code:
+
+(require 'quail)
+
+(quail-define-package
+ "cham" "Cham" "ꨌꩌ" t
+ "A QWERTY-based Cham input method."
+ nil t nil nil t nil nil nil nil nil t)
+
+(quail-define-rules
+ ("a" ?ꨀ)
+ ("A" ?ꨄ)
+ ("i" ?ꨁ)
+ ("u" ?ꨂ)
+ ("e" ?ꨃ)
+ ("o" ?ꨅ)
+ ("k" ?ꨆ)
+ ("K" ?ꨇ)
+ ("g" ?ꨈ)
+ ("G" ?ꨉ)
+ ("q" ?ꨊ)
+ ("Q" ?ꨋ)
+ ("c" ?ꨌ)
+ ("C" ?ꨍ)
+ ("j" ?ꨎ)
+ ("J" ?ꨏ)
+ ("z" ?ꨐ)
+ ("Z" ?ꨑ)
+ ("zz" ?ꨒ)
+ ("t" ?ꨓ)
+ ("T" ?ꨔ)
+ ("d" ?ꨕ)
+ ("D" ?ꨖ)
+ ("n" ?ꨗ)
+ ("N" ?ꨘ)
+ ("p" ?ꨚ)
+ ("P" ?ꨛ)
+ ("f" ?ꨜ)
+ ("b" ?ꨝ)
+ ("B" ?ꨞ)
+ ("m" ?ꨟ)
+ ("M" ?ꨠ)
+ ("mm" ?ꨡ)
+ ("y" ?ꨢ)
+ ("r" ?ꨣ)
+ ("l" ?ꨤ)
+ ("w" ?ꨥ)
+ ("v" ?ꨥ)
+ ("x" ?ꨦ)
+ ("s" ?ꨧ)
+ ("h" ?ꨨ)
+ ("kk" ?ꩀ)
+ ("ww" ?ꩁ)
+ ("vv" ?ꩁ)
+ ("qq" ?ꩂ)
+ ("cc" ?ꩄ)
+ ("tt" ?ꩅ)
+ ("nn" ?ꩆ)
+ ("pp" ?ꩇ)
+ ("yy" ?ꩈ)
+ ("rr" ?ꩉ)
+ ("ll" ?ꩊ)
+ ("gg" ?ꩊ)
+ ("xx" ?ꩋ)
+ ("." ?ꩌ)
+ ("H" ?ꩍ)
+ ("0" ?꩐)
+ ("1" ?꩑)
+ ("2" ?꩒)
+ ("3" ?꩓)
+ ("4" ?꩔)
+ ("5" ?꩕)
+ ("6" ?꩖)
+ ("7" ?꩗)
+ ("8" ?꩘)
+ ("9" ?꩙)
+ ("!" ?ꨩ)
+ ("#" ?ꨪ)
+ ("$" ?ꨫ)
+ ("^" ?ꨬ)
+ ("&" ?ꨮ)
+ ("`" ?꩜)
+ ("=" ?ꨱ)
+ ("-" ?ꩃ)
+ ("~" ?꩟)
+ )
+
+;;; cham.el ends here
diff --git a/lisp/mail/flow-fill.el b/lisp/mail/flow-fill.el
index e93ba547a89..0fab1b21b47 100644
--- a/lisp/mail/flow-fill.el
+++ b/lisp/mail/flow-fill.el
@@ -174,8 +174,8 @@ lines."
 (defvar fill-flowed-encode-tests)
 
 (defun fill-flowed-test ()
-  (interactive "")
   (declare (obsolete nil "27.1"))
+  (interactive "")
   (user-error (concat "This function is obsolete.  Please see "
                       "test/lisp/mail/flow-fill-tests.el "
                       "in the Emacs source tree")))
diff --git a/lisp/mail/footnote.el b/lisp/mail/footnote.el
index ea109eec12a..995ae5f9160 100644
--- a/lisp/mail/footnote.el
+++ b/lisp/mail/footnote.el
@@ -910,7 +910,31 @@ play around with the following keys:
         (unless (assoc bullet-regexp filladapt-token-table)
           (setq filladapt-token-table
                 (append filladapt-token-table
-                        (list (list bullet-regexp 'bullet)))))))))
+                        (list (list bullet-regexp 'bullet)))))))
+    (footnote--regenerate-alist)))
+
+(defun footnote--regenerate-alist ()
+  (save-excursion
+    (goto-char (point-min))
+    (when (re-search-forward footnote-section-tag-regexp nil t)
+      (setq footnote--markers-alist
+            (cl-loop
+             with start-of-footnotes = (match-beginning 0)
+             with regexp = (footnote--current-regexp)
+             for (note text) in
+             (cl-loop for pos = (re-search-forward regexp nil t)
+                      while pos
+                      collect (list (match-string 1)
+                                    (copy-marker (match-beginning 0) t)))
+             do (goto-char (point-min))
+             collect (cl-list*
+                      (string-to-number note)
+                      text
+                      (cl-loop
+                       for pos = (re-search-forward regexp start-of-footnotes t)
+                       while pos
+                       when (equal note (match-string 1))
+                       collect (copy-marker (match-beginning 0) t))))))))
 
 (provide 'footnote)
 
diff --git a/lisp/mail/rmailedit.el b/lisp/mail/rmailedit.el
index 2680ed7f3a3..c3b351d7bc8 100644
--- a/lisp/mail/rmailedit.el
+++ b/lisp/mail/rmailedit.el
@@ -145,8 +145,9 @@ This function runs the hooks `text-mode-hook' and `rmail-edit-mode-hook'.
 (declare-function rmail-summary-enable "rmailsum" ())
 (declare-function rmail-summary-update-line "rmailsum" (n))
 
-(defun rmail-cease-edit ()
-  "Finish editing message; switch back to Rmail proper."
+(defun rmail-cease-edit (&optional abort)
+  "Finish editing message; switch back to Rmail proper.
+If ABORT, this is the result of aborting an edit."
   (interactive)
   (if (rmail-summary-exists)
       (with-current-buffer rmail-summary-buffer
@@ -271,6 +272,8 @@ This function runs the hooks `text-mode-hook' and `rmail-edit-mode-hook'.
            ;; No match for rmail-mime-charset-pattern, but there was some
            ;; other Content-Type.  We should not insert another.  (Bug#4624)
            (content-type)
+           ;; Don't insert anything if aborting.
+           (abort)
            ((null old-coding)
             ;; If there was no charset= spec, insert one.
             (backward-char 1)
@@ -352,7 +355,7 @@ This function runs the hooks `text-mode-hook' and `rmail-edit-mode-hook'.
   (widen)
   (delete-region (point-min) (point-max))
   (insert rmail-old-text)
-  (rmail-cease-edit)
+  (rmail-cease-edit t)
   (rmail-highlight-headers))
 
 (defun rmail-edit-headers-alist (&optional widen markers)
diff --git a/lisp/mail/rmailsum.el b/lisp/mail/rmailsum.el
index 60b67edf85a..d29115a9570 100644
--- a/lisp/mail/rmailsum.el
+++ b/lisp/mail/rmailsum.el
@@ -51,10 +51,10 @@ Setting this option to nil might speed up the generation of summaries."
   :group 'rmail-summary)
 
 (defvar rmail-summary-font-lock-keywords
-  '(("^.....D.*" . font-lock-string-face)                       ; Deleted.
-    ("^.....-.*" . font-lock-type-face)                         ; Unread.
+  '(("^ *[0-9]+D.*" . font-lock-string-face)                    ; Deleted.
+    ("^ *[0-9]+-.*" . font-lock-type-face)                      ; Unread.
     ;; Neither of the below will be highlighted if either of the above are:
-    ("^.....[^D-] \\(......\\)" 1 font-lock-keyword-face)       ; Date.
+    ("^ *[0-9]+[^D-] \\(......\\)" 1 font-lock-keyword-face)    ; Date.
     ("{ \\([^\n}]+\\) }" 1 font-lock-comment-face))             ; Labels.
   "Additional expressions to highlight in Rmail Summary mode.")
 
diff --git a/lisp/mh-e/mh-speed.el b/lisp/mh-e/mh-speed.el
index 35d5884b16c..7cbd42c8ea2 100644
--- a/lisp/mh-e/mh-speed.el
+++ b/lisp/mh-e/mh-speed.el
@@ -125,11 +125,10 @@ With non-nil FORCE, the update is always carried out."
         ;; Otherwise on to your regular programming
         (t t)))
 
-(defun mh-speed-toggle (&rest ignored)
+(defun mh-speed-toggle (&rest _ignored)
   "Toggle the display of child folders in the speedbar.
 The optional arguments from speedbar are IGNORED."
   (interactive)
-  (declare (ignore args))
   (beginning-of-line)
   (let ((parent (get-text-property (point) 'mh-folder))
         (kids-p (get-text-property (point) 'mh-children-p))
@@ -164,11 +163,10 @@ The optional arguments from speedbar are IGNORED."
               (mh-line-beginning-position) (1+ (line-beginning-position))
               '(mh-expanded t)))))))
 
-(defun mh-speed-view (&rest ignored)
+(defun mh-speed-view (&rest _ignored)
   "Visits the selected folder just as if you had used \\<mh-folder-mode-map>\\[mh-visit-folder].
 The optional arguments from speedbar are IGNORED."
   (interactive)
-  (declare (ignore args))
   (let* ((folder (get-text-property (mh-line-beginning-position) 'mh-folder))
          (range (and (stringp folder)
                      (mh-read-range "Scan" folder t nil nil
diff --git a/lisp/net/eww.el b/lisp/net/eww.el
index d131b2bf8c9..e39a4c33b20 100644
--- a/lisp/net/eww.el
+++ b/lisp/net/eww.el
@@ -1050,9 +1050,16 @@ the like."
   ;; multi-page isearch support
   (setq-local multi-isearch-next-buffer-function #'eww-isearch-next-buffer)
   (setq truncate-lines t)
+  (setq-local thing-at-point-provider-alist
+              (append thing-at-point-provider-alist
+                      '((url . eww--url-at-point))))
   (buffer-disable-undo)
   (setq buffer-read-only t))
 
+(defun eww--url-at-point ()
+  "`thing-at-point' provider function."
+  (get-text-property (point) 'shr-url))
+
 ;;;###autoload
 (defun eww-browse-url (url &optional new-window)
   "Ask the EWW browser to load URL.
diff --git a/lisp/net/tramp-sh.el b/lisp/net/tramp-sh.el
index e8ee372cb25..ed3d15377c3 100644
--- a/lisp/net/tramp-sh.el
+++ b/lisp/net/tramp-sh.el
@@ -181,10 +181,9 @@ The string is used in `tramp-methods'.")
               `("scpx"
                 (tramp-login-program        "ssh")
                 (tramp-login-args           (("-l" "%u") ("-p" "%p") ("%c")
-                                             ("-e" "none") ("-t" "-t") ("%h")
-                                             ("%l")))
+                                             ("-e" "none") ("-t" "-t")
+                                             ("-o" "RemoteCommand='%l'") ("%h")))
                 (tramp-async-args           (("-q")))
-                (tramp-direct-async         t)
                 (tramp-remote-shell         ,tramp-default-remote-shell)
                 (tramp-remote-shell-login   ("-l"))
                 (tramp-remote-shell-args    ("-c"))
@@ -238,10 +237,9 @@ The string is used in `tramp-methods'.")
               `("sshx"
                 (tramp-login-program        "ssh")
                 (tramp-login-args           (("-l" "%u") ("-p" "%p") ("%c")
-                                             ("-e" "none") ("-t" "-t") ("%h")
-                                             ("%l")))
+                                             ("-e" "none") ("-t" "-t")
+                                             ("-o" "RemoteCommand='%l'") ("%h")))
                 (tramp-async-args           (("-q")))
-                (tramp-direct-async         t)
                 (tramp-remote-shell         ,tramp-default-remote-shell)
                 (tramp-remote-shell-login   ("-l"))
                 (tramp-remote-shell-args    ("-c"))))
@@ -2608,23 +2606,19 @@ The method used must be an out-of-band method."
 (defun tramp-sh-handle-insert-directory
     (filename switches &optional wildcard full-directory-p)
   "Like `insert-directory' for Tramp files."
-  (setq filename (expand-file-name filename))
   (unless switches (setq switches ""))
   ;; Check, whether directory is accessible.
   (unless wildcard
     (access-file filename "Reading directory"))
-  (with-parsed-tramp-file-name filename nil
+  (with-parsed-tramp-file-name (expand-file-name filename) nil
     (if (and (featurep 'ls-lisp)
              (not (symbol-value 'ls-lisp-use-insert-directory-program)))
         (tramp-handle-insert-directory
          filename switches wildcard full-directory-p)
       (when (stringp switches)
         (setq switches (split-string switches)))
-      (when (tramp-get-ls-command-with ;FIXME: tramp-sh--quoting-style-options?
-             v "--quoting-style=literal --show-control-chars")
-        (setq switches
-              (append
-               switches '("--quoting-style=literal" "--show-control-chars"))))
+      (setq switches
+            (append switches (split-string (tramp-sh--quoting-style-options v))))
       (unless (tramp-get-ls-command-with v "--dired")
         (setq switches (delete "--dired" switches)))
       (when wildcard
@@ -4306,11 +4300,14 @@ file exists and nonzero exit status otherwise."
     ;; ensure they have the correct values when the shell starts, not
     ;; just processes run within the shell.  (Which processes include
     ;; our initial probes to ensure the remote shell is usable.)
+    ;; For the time being, we assume that all shells interpret -i as
+    ;; interactive shell.  Must be the last argument, because (for
+    ;; example) bash expects long options first.
     (tramp-send-command
      vec (format
           (concat
            "exec env TERM='%s' INSIDE_EMACS='%s,tramp:%s' "
-           "ENV=%s %s PROMPT_COMMAND='' PS1=%s PS2='' PS3='' %s %s")
+           "ENV=%s %s PROMPT_COMMAND='' PS1=%s PS2='' PS3='' %s %s -i")
           tramp-terminal-type
           (or (getenv "INSIDE_EMACS") emacs-version) tramp-version
           (or (getenv-internal "ENV" tramp-remote-process-environment) "")
@@ -5122,7 +5119,7 @@ connection if a previous connection has died for some reason."
                      options (format-spec options spec)
                      spec (format-spec-make
                            ?h l-host ?u l-user ?p l-port ?c options
-                           ?l (concat remote-shell " " extra-args))
+                           ?l (concat remote-shell " " extra-args " -i"))
                      command
                      (concat
                       ;; We do not want to see the trailing local
diff --git a/lisp/net/tramp-smb.el b/lisp/net/tramp-smb.el
index 1604e8962c0..c5a74a5c653 100644
--- a/lisp/net/tramp-smb.el
+++ b/lisp/net/tramp-smb.el
@@ -156,6 +156,7 @@ this variable (\"client min protocol=NT1\") ."
          "NT_STATUS_NO_SUCH_FILE"
          "NT_STATUS_NO_SUCH_USER"
          "NT_STATUS_NOT_A_DIRECTORY"
+         "NT_STATUS_NOT_SUPPORTED"
          "NT_STATUS_OBJECT_NAME_COLLISION"
          "NT_STATUS_OBJECT_NAME_INVALID"
          "NT_STATUS_OBJECT_NAME_NOT_FOUND"
@@ -371,17 +372,17 @@ pass to the OPERATION."
         (tramp-error
          v2 'file-error
          "add-name-to-file: %s must not be a directory" filename))
-        ;; Do the 'confirm if exists' thing.
-        (when (file-exists-p newname)
-          ;; What to do?
-          (if (or (null ok-if-already-exists) ; not allowed to exist
-                  (and (numberp ok-if-already-exists)
-                       (not (yes-or-no-p
-                             (format
-                              "File %s already exists; make it a link anyway? "
-                              v2-localname)))))
-              (tramp-error v2 'file-already-exists newname)
-            (delete-file newname)))
+      ;; Do the 'confirm if exists' thing.
+      (when (file-exists-p newname)
+        ;; What to do?
+        (if (or (null ok-if-already-exists) ; not allowed to exist
+                (and (numberp ok-if-already-exists)
+                     (not (yes-or-no-p
+                           (format
+                            "File %s already exists; make it a link anyway? "
+                            v2-localname)))))
+            (tramp-error v2 'file-already-exists newname)
+          (delete-file newname)))
       ;; We must also flush the cache of the directory, because
       ;; `file-attributes' reads the values from there.
       (tramp-flush-file-properties v2 v2-localname)
@@ -1166,7 +1167,6 @@ PRESERVE-UID-GID and PRESERVE-EXTENDED-ATTRIBUTES are completely ignored."
                    (insert " -> " (tramp-compat-file-attribute-type attr))))
 
                (insert "\n")
-               (forward-line)
                (beginning-of-line)))
            entries))))))
 
diff --git a/lisp/net/tramp.el b/lisp/net/tramp.el
index 2816c58fe7f..7b34a748822 100644
--- a/lisp/net/tramp.el
+++ b/lisp/net/tramp.el
@@ -1990,6 +1990,8 @@ the resulting error message."
              (tramp-dissect-file-name default-directory) 0 fmt-string arguments)
     (apply #'message fmt-string arguments)))
 
+(put #'tramp-test-message 'tramp-suppress-trace t)
+
 ;; This function provides traces in case of errors not triggered by
 ;; Tramp functions.
 (defun tramp-signal-hook-function (error-symbol data)
@@ -3801,15 +3803,20 @@ It does not support `:stderr'."
                     (get-buffer-create buffer)
                   ;; BUFFER can be nil.  We use a temporary buffer.
                   (generate-new-buffer tramp-temp-buffer-name)))
-               ;; We use as environment the difference to toplevel
-               ;; `process-environment'.
                (env (mapcar
                      (lambda (elt)
-                       (unless
-                           (member
-                            elt (default-toplevel-value 'process-environment))
-                         (when (string-match-p "=" elt) elt)))
-                     process-environment))
+                       (when (string-match-p "=" elt) elt))
+                     tramp-remote-process-environment))
+               ;; We use as environment the difference to toplevel
+               ;; `process-environment'.
+               (env (dolist (elt process-environment env)
+                      (when
+                          (and
+                           (string-match-p "=" elt)
+                           (not
+                            (member
+                             elt (default-toplevel-value 'process-environment))))
+                        (setq env (cons elt env)))))
                (env (setenv-internal
                      env "INSIDE_EMACS"
                      (concat (or (getenv "INSIDE_EMACS") emacs-version)
diff --git a/lisp/net/webjump.el b/lisp/net/webjump.el
index 9bcf1d37345..e5941ae652e 100644
--- a/lisp/net/webjump.el
+++ b/lisp/net/webjump.el
@@ -2,9 +2,10 @@
 
 ;; Copyright (C) 1996-1997, 2001-2021 Free Software Foundation, Inc.
 
-;; Author:    Neil W. Van Dyke <nwv@acm.org>
-;; Created:   09-Aug-1996
-;; Keywords:  comm www
+;; Author:     Neil W. Van Dyke <nwv@acm.org>
+;; Maintainer: emacs-devel@gnu.org
+;; Created:    09-Aug-1996
+;; Keywords:   comm www
 
 ;; This file is part of GNU Emacs.
 
diff --git a/lisp/nxml/nxml-mode.el b/lisp/nxml/nxml-mode.el
index 5bc3049d90f..0602943db20 100644
--- a/lisp/nxml/nxml-mode.el
+++ b/lisp/nxml/nxml-mode.el
@@ -54,26 +54,30 @@
   "Non-nil means display glyph following character reference.
 The glyph is displayed in face `nxml-glyph'."
   :group 'nxml
-  :type 'boolean)
+  :type 'boolean
+  :safe #'booleanp)
 
 (defcustom nxml-sexp-element-flag t
   "Non-nil means sexp commands treat an element as a single expression."
   :version "27.1"                       ; nil -> t
   :group 'nxml
-  :type 'boolean)
+  :type 'boolean
+  :safe #'booleanp)
 
 (defcustom nxml-slash-auto-complete-flag nil
   "Non-nil means typing a slash automatically completes the end-tag.
 This is used by `nxml-electric-slash'."
   :group 'nxml
-  :type 'boolean)
+  :type 'boolean
+  :safe #'booleanp)
 
 (defcustom nxml-child-indent 2
   "Indentation for the children of an element relative to the start-tag.
 This only applies when the line or lines containing the start-tag contains
 nothing else other than that start-tag."
   :group 'nxml
-  :type 'integer)
+  :type 'integer
+  :safe #'integerp)
 
 (defcustom nxml-attribute-indent 4
   "Indentation for the attributes of an element relative to the start-tag.
@@ -81,12 +85,14 @@ This only applies when the first attribute of a tag starts a line.
 In other cases, the first attribute on one line is indented the same
 as the first attribute on the previous line."
   :group 'nxml
-  :type 'integer)
+  :type 'integer
+  :safe #'integerp)
 
 (defcustom nxml-bind-meta-tab-to-complete-flag t
   "Non-nil means to use nXML completion in \\[completion-at-point]."
   :group 'nxml
-  :type 'boolean)
+  :type 'boolean
+  :safe #'booleanp)
 
 (defcustom nxml-prefer-utf-16-to-utf-8-flag nil
   "Non-nil means prefer UTF-16 to UTF-8 when saving a buffer.
@@ -94,7 +100,8 @@ This is used only when a buffer does not contain an encoding declaration
 and when its current `buffer-file-coding-system' specifies neither UTF-16
 nor UTF-8."
   :group 'nxml
-  :type 'boolean)
+  :type 'boolean
+  :safe #'booleanp)
 
 (defcustom nxml-prefer-utf-16-little-to-big-endian-flag (eq system-type
                                                             'windows-nt)
@@ -103,7 +110,8 @@ This is used only for saving a buffer; when reading the byte-order is
 auto-detected. It may be relevant both when there is no encoding declaration
 and when the encoding declaration specifies `UTF-16'."
   :group 'nxml
-  :type 'boolean)
+  :type 'boolean
+  :safe #'booleanp)
 
 (defcustom nxml-default-buffer-file-coding-system nil
   "Default value for `buffer-file-coding-system' for a buffer for a new file.
@@ -112,13 +120,15 @@ A value of nil means use the default value of
 A buffer's `buffer-file-coding-system' affects what
 \\[nxml-insert-xml-declaration] inserts."
   :group 'nxml
-  :type 'coding-system)
+  :type 'coding-system
+  :safe #'coding-system-p)
 
 (defcustom nxml-auto-insert-xml-declaration-flag nil
   "Non-nil means automatically insert an XML declaration in a new file.
 The XML declaration is inserted using `nxml-insert-xml-declaration'."
   :group 'nxml
-  :type 'boolean)
+  :type 'boolean
+  :safe #'booleanp)
 
 (defface nxml-delimited-data
   '((t (:inherit font-lock-doc-face)))
diff --git a/lisp/obsolete/nnir.el b/lisp/obsolete/nnir.el
index 147efed0057..0b7d1e454c3 100644
--- a/lisp/obsolete/nnir.el
+++ b/lisp/obsolete/nnir.el
@@ -504,7 +504,6 @@ Add an entry here when adding a new search engine.")
                         ,@(mapcar (lambda (elem) (list 'const (car elem)))
                                   nnir-engines)))))
 
-
 (defmacro nnir-add-result (dirnam artno score prefix server artlist)
   "Construct a result vector and add it to ARTLIST.
 DIRNAM, ARTNO, SCORE, PREFIX and SERVER are passed to
diff --git a/lisp/progmodes/perl-mode.el b/lisp/progmodes/perl-mode.el
index 2a2a4978c62..d047dd543c2 100644
--- a/lisp/progmodes/perl-mode.el
+++ b/lisp/progmodes/perl-mode.el
@@ -95,6 +95,12 @@
   :prefix "perl-"
   :group 'languages)
 
+(defface perl-non-scalar-variable
+  '((t :inherit font-lock-variable-name-face :underline t))
+  "Face used for non-scalar variables."
+  :version "28.1"
+  :group 'perl)
+
 (defvar perl-mode-abbrev-table nil
   "Abbrev table in use in perl-mode buffers.")
 (define-abbrev-table 'perl-mode-abbrev-table ())
@@ -187,11 +193,12 @@
      ;;
      ;; Fontify function, variable and file name references.
      ("&\\(\\sw+\\(::\\sw+\\)*\\)" 1 font-lock-function-name-face)
-     ;; Additionally underline non-scalar variables.  Maybe this is a bad idea.
+     ;; Additionally fontify non-scalar variables.  `perl-non-scalar-variable'
+     ;; will underline them by default.
      ;;'("[$@%*][#{]?\\(\\sw+\\)" 1 font-lock-variable-name-face)
      ("[$*]{?\\(\\sw+\\(::\\sw+\\)*\\)" 1 font-lock-variable-name-face)
      ("\\([@%]\\|\\$#\\)\\(\\sw+\\(::\\sw+\\)*\\)"
-      (2 (cons font-lock-variable-name-face '(underline))))
+      (2 'perl-non-scalar-variable))
      ("<\\(\\sw+\\)>" 1 font-lock-constant-face)
      ;;
      ;; Fontify keywords with/and labels as we do in `c++-font-lock-keywords'.
diff --git a/lisp/progmodes/project.el b/lisp/progmodes/project.el
index 06966f33b72..768cd58ae44 100644
--- a/lisp/progmodes/project.el
+++ b/lisp/progmodes/project.el
@@ -928,6 +928,7 @@ if one already exists."
 ;;;###autoload
 (defun project-async-shell-command ()
   "Run `async-shell-command' in the current project's root directory."
+  (declare (interactive-only async-shell-command))
   (interactive)
   (let ((default-directory (project-root (project-current t))))
     (call-interactively #'async-shell-command)))
@@ -935,6 +936,7 @@ if one already exists."
 ;;;###autoload
 (defun project-shell-command ()
   "Run `shell-command' in the current project's root directory."
+  (declare (interactive-only shell-command))
   (interactive)
   (let ((default-directory (project-root (project-current t))))
     (call-interactively #'shell-command)))
@@ -972,6 +974,7 @@ loop using the command \\[fileloop-continue]."
 ;;;###autoload
 (defun project-compile ()
   "Run `compile' in the project root."
+  (declare (interactive-only compile))
   (interactive)
   (let ((default-directory (project-root (project-current t))))
     (call-interactively #'compile)))
diff --git a/lisp/progmodes/sh-script.el b/lisp/progmodes/sh-script.el
index a417de32640..cc045a1b2d1 100644
--- a/lisp/progmodes/sh-script.el
+++ b/lisp/progmodes/sh-script.el
@@ -1556,7 +1556,7 @@ with your script for an edit-interpret-debug cycle."
   (sh-set-shell
    (cond ((save-excursion
             (goto-char (point-min))
-            (looking-at "#![ \t]?\\([^ \t\n]*/bin/env[ \t]\\)?\\([^ \t\n]+\\)"))
+            (looking-at auto-mode-interpreter-regexp))
           (match-string 2))
          ((not buffer-file-name) sh-shell-file)
          ;; Checks that use `buffer-file-name' follow.
@@ -2927,8 +2927,8 @@ option followed by a colon `:' if the option accepts an argument."
 (put 'sh-assignment 'delete-selection t)
 (defun sh-assignment (arg)
   "Remember preceding identifier for future completion and do self-insert."
-  (interactive "p")
   (declare (obsolete nil "27.1"))
+  (interactive "p")
   (self-insert-command arg)
   (sh--assignment-collect))
 
diff --git a/lisp/progmodes/xref.el b/lisp/progmodes/xref.el
index b6778de807d..898cb4fb4c1 100644
--- a/lisp/progmodes/xref.el
+++ b/lisp/progmodes/xref.el
@@ -967,16 +967,15 @@ Return an alist of the form ((FILENAME . (XREF ...)) ...)."
   (let ((inhibit-read-only t)
         (buffer-undo-list t))
     (save-excursion
-      (erase-buffer)
       (condition-case err
-          (xref--insert-xrefs
-           (xref--analyze (funcall xref--fetcher)))
+          (let ((alist (xref--analyze (funcall xref--fetcher))))
+            (erase-buffer)
+            (xref--insert-xrefs alist))
         (user-error
          (insert
           (propertize
            (error-message-string err)
-           'face 'error))))
-      (goto-char (point-min)))))
+           'face 'error)))))))
 
 (defun xref-show-definitions-buffer (fetcher alist)
   "Show the definitions list in a regular window.
@@ -1001,8 +1000,12 @@ When only one definition found, jump to it right away instead."
 When there is more than one definition, split the selected window
 and show the list in a small window at the bottom.  And use a
 local keymap that binds `RET' to `xref-quit-and-goto-xref'."
-  (let ((xrefs (funcall fetcher))
-        (dd default-directory))
+  (let* ((xrefs (funcall fetcher))
+         (dd default-directory)
+         ;; XXX: Make percentage customizable maybe?
+         (max-height (/ (window-height) 2))
+         (size-fun (lambda (window)
+                     (fit-window-to-buffer window max-height))))
     (cond
      ((not (cdr xrefs))
       (xref-pop-to-location (car xrefs)
@@ -1013,7 +1016,8 @@ local keymap that binds `RET' to `xref-quit-and-goto-xref'."
         (xref--transient-buffer-mode)
         (xref--show-common-initialize (xref--analyze xrefs) fetcher alist)
         (pop-to-buffer (current-buffer)
-                       '(display-buffer-in-direction . ((direction . below))))
+                       `(display-buffer-in-direction . ((direction . below)
+                                                        (window-height . ,size-fun))))
         (current-buffer))))))
 
 (define-obsolete-function-alias 'xref--show-defs-buffer-at-bottom
diff --git a/lisp/replace.el b/lisp/replace.el
index d41dc98a0d9..db5b340631a 100644
--- a/lisp/replace.el
+++ b/lisp/replace.el
@@ -866,13 +866,10 @@ If nil, uses `regexp-history'."
          ;; Do not automatically add default to the history for empty input.
          (history-add-new-input nil)
          (input (read-from-minibuffer
-                 (cond ((string-match-p ":[ \t]*\\'" prompt)
-                        prompt)
-                       ((and default (> (length default) 0))
-                         (format "%s (default %s): " prompt
-                                 (query-replace-descr default)))
-                       (t
-                        (format "%s: " prompt)))
+                 (if (string-match-p ":[ \t]*\\'" prompt)
+                     prompt
+                   (format-prompt prompt (and (length> default 0)
+                                              (query-replace-descr default))))
                  nil nil nil (or history 'regexp-history) suggestions t)))
     (if (equal input "")
         ;; Return the default value when the user enters empty input.
@@ -2428,23 +2425,27 @@ It is called with three arguments, as if it were
         (overlay-put replace-overlay 'priority 1001) ;higher than lazy overlays
         (overlay-put replace-overlay 'face 'query-replace)))
 
-  (when (and query-replace-highlight-submatches
-             regexp-flag)
+  (when (and query-replace-highlight-submatches regexp-flag)
     (mapc 'delete-overlay replace-submatches-overlays)
     (setq replace-submatches-overlays nil)
-    (let ((submatch-data (cddr (butlast (match-data t))))
+    ;; 'cddr' removes whole expression match from match-data
+    (let ((submatch-data (cddr (match-data t)))
           (group 0)
-          ov face)
+          b e ov face)
       (while submatch-data
-        (setq group (1+ group))
-        (setq ov (make-overlay (pop submatch-data) (pop submatch-data))
-              face (intern-soft (format "isearch-group-%d" group)))
-        ;; Recycle faces from beginning.
-        (unless (facep face)
-          (setq group 1 face 'isearch-group-1))
-        (overlay-put ov 'face face)
-        (overlay-put ov 'priority 1002)
-        (push ov replace-submatches-overlays))))
+        (setq b (pop submatch-data)
+              e (pop submatch-data))
+        (when (and (integer-or-marker-p b)
+                   (integer-or-marker-p e))
+          (setq ov (make-overlay b e)
+                group (1+ group)
+                face (intern-soft (format "isearch-group-%d" group)))
+          ;; Recycle faces from beginning
+          (unless (facep face)
+            (setq group 1 face 'isearch-group-1))
+          (overlay-put ov 'face face)
+          (overlay-put ov 'priority 1002)
+          (push ov replace-submatches-overlays)))))
 
   (if query-replace-lazy-highlight
       (let ((isearch-string search-string)
diff --git a/lisp/simple.el b/lisp/simple.el
index 37c0885dcc5..8d4e4a7a6bb 100644
--- a/lisp/simple.el
+++ b/lisp/simple.el
@@ -820,9 +820,10 @@ With ARG, perform this action that many times."
   (delete-horizontal-space t)
   (unless arg
     (setq arg 1))
-  (dotimes (_ arg)
-    (newline nil t)
-    (indent-according-to-mode)))
+  (let ((electric-indent-mode nil))
+    (dotimes (_ arg)
+      (newline nil t)
+      (indent-according-to-mode))))
 
 (defun reindent-then-newline-and-indent ()
   "Reindent current line, insert newline, then indent the new line.
@@ -832,7 +833,8 @@ In programming language modes, this is the same as TAB.
 In some text modes, where TAB inserts a tab, this indents to the
 column specified by the function `current-left-margin'."
   (interactive "*")
-  (let ((pos (point)))
+  (let ((pos (point))
+        (electric-indent-mode nil))
     ;; Be careful to insert the newline before indenting the line.
     ;; Otherwise, the indentation might be wrong.
     (newline)
@@ -7338,10 +7340,7 @@ even beep.)"
   ;; of the kill before killing.
   (let ((opoint (point))
         (kill-whole-line (and kill-whole-line (bolp)))
-        (orig-y (cdr (nth 2 (posn-at-point))))
-        ;; FIXME: This tolerance should be zero!  It isn't due to a
-        ;; bug in posn-at-point, see bug#45837.
-        (tol (/ (line-pixel-height) 2)))
+        (orig-vlnum (cdr (nth 6 (posn-at-point)))))
     (if arg
         (vertical-motion (prefix-numeric-value arg))
       (end-of-visual-line 1)
@@ -7352,8 +7351,8 @@ even beep.)"
         ;; end-of-visual-line didn't overshoot due to complications
         ;; like display or overlay strings, intangible text, etc.:
         ;; otherwise, we don't want to kill a character that's
-        ;; unrelated to the place where the visual line wrapped.
-        (and (< (abs (- (cdr (nth 2 (posn-at-point))) orig-y)) tol)
+        ;; unrelated to the place where the visual line wraps.
+        (and (= (cdr (nth 6 (posn-at-point))) orig-vlnum)
              ;; Make sure we delete the character where the line wraps
              ;; under visual-line-mode, be it whitespace or a
              ;; character whose category set allows to wrap at it.
diff --git a/lisp/startup.el b/lisp/startup.el
index 9325ab5acff..09635b12990 100644
--- a/lisp/startup.el
+++ b/lisp/startup.el
@@ -1180,6 +1180,7 @@ please check its value")
         ;; are dependencies between them.
         (nreverse custom-delayed-init-variables))
   (mapc #'custom-reevaluate-setting custom-delayed-init-variables)
+  (setq custom-delayed-init-variables nil)
 
   ;; Warn for invalid user name.
   (when init-file-user
@@ -1309,12 +1310,6 @@ please check its value")
     (startup--setup-quote-display)
     (setq internal--text-quoting-flag t))
 
-  ;; Re-evaluate again the predefined variables whose initial value
-  ;; depends on the runtime context, in case some of them depend on
-  ;; the window-system features.  Example: blink-cursor-mode.
-  (mapc #'custom-reevaluate-setting custom-delayed-init-variables)
-  (setq custom-delayed-init-variables nil)
-
   (normal-erase-is-backspace-setup-frame)
 
   ;; Register default TTY colors for the case the terminal hasn't a
@@ -1495,13 +1490,13 @@ to reading the init file), or afterwards when the user first
 opens a graphical frame.
 
 This can set the values of `menu-bar-mode', `tool-bar-mode',
-`tab-bar-mode', and `no-blinking-cursor', as well as the `cursor' face.
+`tab-bar-mode', and `blink-cursor-mode', as well as the `cursor' face.
 Changed settings will be marked as \"CHANGED outside of Customize\"."
   (let ((no-vals  '("no" "off" "false" "0"))
         (settings '(("menuBar" "MenuBar" menu-bar-mode nil)
                     ("toolBar" "ToolBar" tool-bar-mode nil)
                     ("scrollBar" "ScrollBar" scroll-bar-mode nil)
-                    ("cursorBlink" "CursorBlink" no-blinking-cursor t))))
+                    ("cursorBlink" "CursorBlink" blink-cursor-mode nil))))
     (dolist (x settings)
       (if (member (x-get-resource (nth 0 x) (nth 1 x)) no-vals)
           (set (nth 2 x) (nth 3 x)))))
diff --git a/lisp/term/ns-win.el b/lisp/term/ns-win.el
index 5f4dd9ef587..94e9d5c5828 100644
--- a/lisp/term/ns-win.el
+++ b/lisp/term/ns-win.el
@@ -120,6 +120,15 @@ The properties returned may include `top', `left', `height', and `width'."
 (define-key global-map [?\s-d] 'isearch-repeat-backward)
 (define-key global-map [?\s-e] 'isearch-yank-kill)
 (define-key global-map [?\s-f] 'isearch-forward)
+(define-key esc-map [?\s-f] 'isearch-forward-regexp)
+(define-key minibuffer-local-isearch-map [?\s-f]
+  'isearch-forward-exit-minibuffer)
+(define-key isearch-mode-map [?\s-f] 'isearch-repeat-forward)
+(define-key global-map [?\s-F] 'isearch-backward)
+(define-key esc-map [?\s-F] 'isearch-backward-regexp)
+(define-key minibuffer-local-isearch-map [?\s-F]
+  'isearch-reverse-exit-minibuffer)
+(define-key isearch-mode-map [?\s-F] 'isearch-repeat-backward)
 (define-key global-map [?\s-g] 'isearch-repeat-forward)
 (define-key global-map [?\s-h] 'ns-do-hide-emacs)
 (define-key global-map [?\s-H] 'ns-do-hide-others)
diff --git a/lisp/textmodes/remember.el b/lisp/textmodes/remember.el
index 98d3a3856ea..820ee38d101 100644
--- a/lisp/textmodes/remember.el
+++ b/lisp/textmodes/remember.el
@@ -159,7 +159,8 @@
 ;;   ;; This should be before other entries that may return t
 ;;   (add-to-list 'remember-handler-functions 'remember-diary-extract-entries)
 ;;
-;; This module recognizes entries of the form
+;; This module recognizes entries of the form (defined by
+;; `remember-diary-regexp')
 ;;
 ;;   DIARY: ....
 ;;
@@ -410,13 +411,24 @@ The default emulates `current-time-string' for backward compatibility."
   :group 'remember
   :version "27.1")
 
+(defcustom remember-text-format-function nil
+  "The function to format the remembered text.
+The function receives the remembered text as argument and should
+return the text to be remembered."
+  :type '(choice (const nil) function)
+  :group 'remember
+  :version "28.1")
+
 (defun remember-append-to-file ()
   "Remember, with description DESC, the given TEXT."
   (let* ((text (buffer-string))
          (desc (remember-buffer-desc))
-         (remember-text (concat "\n" remember-leader-text
-                                (format-time-string remember-time-format)
-                                " (" desc ")\n\n" text
+         (remember-text (concat "\n"
+                                (if remember-text-format-function
+                                    (funcall remember-text-format-function text)
+                                  (concat remember-leader-text
+                                          (format-time-string remember-time-format)
+                                          " (" desc ")\n\n" text))
                                 (save-excursion (goto-char (point-max))
                                                 (if (bolp) nil "\n"))))
          (buf (find-buffer-visiting remember-data-file)))
@@ -532,17 +544,28 @@ If this is nil, then `diary-file' will be used instead."
 
 (autoload 'diary-make-entry "diary-lib")
 
+(defcustom remember-diary-regexp "^DIARY:\\s-*\\(.+\\)"
+  "Regexp to extract diary entries."
+  :type 'regexp
+  :version "28.1")
+
+(defvar diary-file)
+
 ;;;###autoload
 (defun remember-diary-extract-entries ()
-  "Extract diary entries from the region."
+  "Extract diary entries from the region based on `remember-diary-regexp'."
   (save-excursion
     (goto-char (point-min))
     (let (list)
-      (while (re-search-forward "^DIARY:\\s-*\\(.+\\)" nil t)
+      (while (re-search-forward remember-diary-regexp nil t)
         (push (remember-diary-convert-entry (match-string 1)) list))
       (when list
         (diary-make-entry (mapconcat 'identity list "\n")
-                          nil remember-diary-file))
+                          nil remember-diary-file)
+        (when remember-save-after-remembering
+          (with-current-buffer (find-buffer-visiting (or remember-diary-file
+                                                         diary-file))
+            (save-buffer))))
       nil))) ;; Continue processing
 
 ;;; Internal Functions:
diff --git a/lisp/thingatpt.el b/lisp/thingatpt.el
index d3ba941fcc2..c52fcfcc051 100644
--- a/lisp/thingatpt.el
+++ b/lisp/thingatpt.el
@@ -52,8 +52,30 @@
 
 ;;; Code:
 
+(require 'cl-lib)
 (provide 'thingatpt)
 
+(defvar thing-at-point-provider-alist nil
+  "Alist of providers for returning a \"thing\" at point.
+This variable can be set globally, or appended to buffer-locally
+by modes, to provide functions that will return a \"thing\" at
+point.  The first provider for the \"thing\" that returns a
+non-nil value wins.
+
+For instance, a major mode could say:
+
+\(setq-local thing-at-point-provider-alist
+            (append thing-at-point-provider-alist
+                    \\='((url . my-mode--url-at-point))))
+
+to provide a way to get an `url' at point in that mode.  The
+provider functions are called with no parameters at the point in
+question.
+
+\"things\" include `symbol', `list', `sexp', `defun', `filename',
+`url', `email', `uuid', `word', `sentence', `whitespace', `line',
+and `page'.")
+
 ;; Basic movement
 
 ;;;###autoload
@@ -143,11 +165,18 @@ strip text properties from the return value.
 See the file `thingatpt.el' for documentation on how to define
 a symbol as a valid THING."
   (let ((text
-         (if (get thing 'thing-at-point)
-             (funcall (get thing 'thing-at-point))
+         (cond
+          ((cl-loop for (pthing . function) in thing-at-point-provider-alist
+                    when (eq pthing thing)
+                    for result = (funcall function)
+                    when result
+                    return result))
+          ((get thing 'thing-at-point)
+           (funcall (get thing 'thing-at-point)))
+          (t
            (let ((bounds (bounds-of-thing-at-point thing)))
              (when bounds
-               (buffer-substring (car bounds) (cdr bounds)))))))
+               (buffer-substring (car bounds) (cdr bounds))))))))
     (when (and text no-properties (sequencep text))
       (set-text-properties 0 (length text) nil text))
     text))
@@ -218,6 +247,15 @@ The bounds of THING are determined by `bounds-of-thing-at-point'."
 
 (put 'sexp 'beginning-op 'thing-at-point--beginning-of-sexp)
 
+;; Symbols
+
+(put 'symbol 'beginning-op 'thing-at-point--beginning-of-symbol)
+
+(defun thing-at-point--beginning-of-symbol ()
+  "Move point to the beginning of the current symbol."
+  (and (re-search-backward "\\(\\sw\\|\\s_\\)+")
+       (skip-syntax-backward "w_")))
+
 ;;  Lists
 
 (put 'list 'bounds-of-thing-at-point 'thing-at-point-bounds-of-list-at-point)
diff --git a/lisp/type-break.el b/lisp/type-break.el
index 84c240c9f8c..a6d5cd01702 100644
--- a/lisp/type-break.el
+++ b/lisp/type-break.el
@@ -487,7 +487,7 @@ Return nil if the file is missing or if the time is not a Lisp time value."
                  (goto-char (point-min))
                  (read (current-buffer)))
              (end-of-file
-              (error "End of file in `%s'" file))))))))
+              (warn "End of file in `%s'" file))))))))
 
 (defun type-break-get-previous-count ()
   "Get previous keystroke count from `type-break-file-name'.
@@ -505,7 +505,7 @@ integer."
                           (forward-line 1)
                           (read (current-buffer)))
                       (end-of-file
-                       (error "End of file in `%s'" file)))))))
+                       (warn "End of file in `%s'" file)))))))
         file
       0)))
 
diff --git a/lisp/vc/vc.el b/lisp/vc/vc.el
index 6c96d8ca7c4..bc9f11202b1 100644
--- a/lisp/vc/vc.el
+++ b/lisp/vc/vc.el
@@ -2392,6 +2392,7 @@ If it contains `file', show short logs for files.
 Not all VC backends support short logs!")
 
 (defvar log-view-vc-fileset)
+(defvar log-view-message-re)
 
 (defun vc-print-log-setup-buttons (working-revision is-start-revision limit pl-return)
   "Insert at the end of the current buffer buttons to show more log entries.
@@ -2401,21 +2402,32 @@ Does nothing if IS-START-REVISION is non-nil, or if LIMIT is nil,
 or if PL-RETURN is `limit-unsupported'."
   (when (and limit (not (eq 'limit-unsupported pl-return))
              (not is-start-revision))
-    (goto-char (point-max))
-    (insert "\n")
-    (insert-text-button "Show 2X entries"
-                        'action (lambda (&rest _ignore)
-                                  (vc-print-log-internal
-                                   log-view-vc-backend log-view-vc-fileset
-                                   working-revision nil (* 2 limit)))
-                        'help-echo "Show the log again, and double the number of log entries shown")
-    (insert "    ")
-    (insert-text-button "Show unlimited entries"
-                        'action (lambda (&rest _ignore)
-                                  (vc-print-log-internal
-                                   log-view-vc-backend log-view-vc-fileset
-                                   working-revision nil nil))
-                        'help-echo "Show the log again, including all entries")))
+    (let ((entries 0))
+      (goto-char (point-min))
+      (while (re-search-forward log-view-message-re nil t)
+        (cl-incf entries))
+      ;; If we got fewer entries than we asked for, then displaying
+      ;; the "more" buttons isn't useful.
+      (when (>= entries limit)
+        (goto-char (point-max))
+        (insert "\n")
+        (insert-text-button
+         "Show 2X entries"
+         'action (lambda (&rest _ignore)
+                   (vc-print-log-internal
+                    log-view-vc-backend log-view-vc-fileset
+                    working-revision nil (* 2 limit)))
+         'help-echo
+         "Show the log again, and double the number of log entries shown")
+        (insert "    ")
+        (insert-text-button
+         "Show unlimited entries"
+         'action (lambda (&rest _ignore)
+                   (vc-print-log-internal
+                    log-view-vc-backend log-view-vc-fileset
+                    working-revision nil nil))
+         'help-echo "Show the log again, including all entries")
+        (insert "\n")))))
 
 (defun vc-print-log-internal (backend files working-revision
                                       &optional is-start-revision limit type)
diff --git a/lisp/version.el b/lisp/version.el
index fcfc2f8b806..3a3093fdd4a 100644
--- a/lisp/version.el
+++ b/lisp/version.el
@@ -29,14 +29,12 @@
 (defconst emacs-major-version
   (progn (string-match "^[0-9]+" emacs-version)
          (string-to-number (match-string 0 emacs-version)))
-  "Major version number of this version of Emacs.
-This variable first existed in version 19.23.")
+  "Major version number of this version of Emacs.")
 
 (defconst emacs-minor-version
   (progn (string-match "^[0-9]+\\.\\([0-9]+\\)" emacs-version)
          (string-to-number (match-string 1 emacs-version)))
-  "Minor version number of this version of Emacs.
-This variable first existed in version 19.23.")
+  "Minor version number of this version of Emacs.")
 
 (defconst emacs-build-system (system-name)
   "Name of the system on which Emacs was built, or nil if not available.")
diff --git a/lisp/wid-edit.el b/lisp/wid-edit.el
index 7dda04eda21..68a0d3d2356 100644
--- a/lisp/wid-edit.el
+++ b/lisp/wid-edit.el
@@ -4026,17 +4026,19 @@ is inline."
 
 ;;; The `color' Widget.
 
-;; Fixme: match
 (define-widget 'color 'editable-field
   "Choose a color name (with sample)."
   :format "%{%t%}: %v (%{sample%})\n"
   :value-create 'widget-color-value-create
-  :size 10
+  :size (1+ (apply #'max 13 ; Longest RGB hex string.
+                   (mapcar #'length (defined-colors))))
   :tag "Color"
   :value "black"
   :completions (or facemenu-color-alist (defined-colors))
   :sample-face-get 'widget-color-sample-face-get
   :notify 'widget-color-notify
+  :match #'widget-color-match
+  :validate #'widget-color-validate
   :action 'widget-color-action)
 
 (defun widget-color-value-create (widget)
@@ -4085,6 +4087,19 @@ is inline."
   (overlay-put (widget-get widget :sample-overlay)
                'face (widget-apply widget :sample-face-get))
   (widget-default-notify widget child event))
+
+(defun widget-color-match (_widget value)
+  "Non-nil if VALUE is a defined color or a RGB hex string."
+  (and (stringp value)
+       (or (color-defined-p value)
+           (string-match-p "^#\\(?:[[:xdigit:]]\\{3\\}\\)\\{1,4\\}$" value))))
+
+(defun widget-color-validate (widget)
+  "Check that WIDGET's value is a valid color."
+  (let ((value (widget-value widget)))
+    (unless (widget-color-match widget value)
+      (widget-put widget :error (format "Invalid color: %S" value))
+      widget)))
 
 ;;; The Help Echo
 
diff --git a/m4/canonicalize.m4 b/m4/canonicalize.m4
index 475fa15d6bd..0dfb2da9a6a 100644
--- a/m4/canonicalize.m4
+++ b/m4/canonicalize.m4
@@ -1,4 +1,4 @@
-# canonicalize.m4 serial 35
+# canonicalize.m4 serial 37
 
 dnl Copyright (C) 2003-2007, 2009-2021 Free Software Foundation, Inc.
 
@@ -78,68 +78,106 @@ AC_DEFUN([gl_CANONICALIZE_LGPL_SEPARATE],
 # so is the latter.
 AC_DEFUN([gl_FUNC_REALPATH_WORKS],
 [
-  AC_CHECK_FUNCS_ONCE([realpath])
+  AC_CHECK_FUNCS_ONCE([realpath lstat])
   AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
   AC_CACHE_CHECK([whether realpath works], [gl_cv_func_realpath_works], [
     rm -rf conftest.a conftest.d
     touch conftest.a
+    # Assume that if we have lstat, we can also check symlinks.
+    if test $ac_cv_func_lstat = yes; then
+      ln -s conftest.a conftest.l
+    fi
     mkdir conftest.d
     AC_RUN_IFELSE([
       AC_LANG_PROGRAM([[
         ]GL_NOCRASH[
+        #include <errno.h>
         #include <stdlib.h>
         #include <string.h>
       ]], [[
         int result = 0;
+        /* This test fails on Solaris 10.  */
         {
           char *name = realpath ("conftest.a", NULL);
           if (!(name && *name == '/'))
             result |= 1;
           free (name);
         }
+        /* This test fails on older versions of Cygwin.  */
         {
           char *name = realpath ("conftest.b/../conftest.a", NULL);
           if (name != NULL)
             result |= 2;
           free (name);
         }
+        /* This test fails on Cygwin 2.9.  */
+        #if HAVE_LSTAT
+        {
+          char *name = realpath ("conftest.l/../conftest.a", NULL);
+          if (name != NULL || errno != ENOTDIR)
+            result |= 4;
+          free (name);
+        }
+        #endif
+        /* This test fails on Mac OS X 10.13, OpenBSD 6.0.  */
         {
           char *name = realpath ("conftest.a/", NULL);
           if (name != NULL)
-            result |= 4;
+            result |= 8;
           free (name);
         }
+        /* This test fails on AIX 7, Solaris 10.  */
         {
           char *name1 = realpath (".", NULL);
           char *name2 = realpath ("conftest.d//./..", NULL);
           if (! name1 || ! name2 || strcmp (name1, name2))
-            result |= 8;
+            result |= 16;
           free (name1);
           free (name2);
         }
+        #ifdef __linux__
+        /* On Linux, // is the same as /. See also double-slash-root.m4.
+           realpath() should respect this.
+           This test fails on musl libc 1.2.2.  */
+        {
+          char *name = realpath ("//", NULL);
+          if (! name || strcmp (name, "/"))
+            result |= 32;
+          free (name);
+        }
+        #endif
         return result;
       ]])
      ],
      [gl_cv_func_realpath_works=yes],
-     [gl_cv_func_realpath_works=no],
+     [case $? in
+        32) gl_cv_func_realpath_works=nearly ;;
+        *)  gl_cv_func_realpath_works=no ;;
+      esac
+     ],
      [case "$host_os" in
                        # Guess yes on glibc systems.
         *-gnu* | gnu*) gl_cv_func_realpath_works="guessing yes" ;;
-                       # Guess yes on musl systems.
-        *-musl*)       gl_cv_func_realpath_works="guessing yes" ;;
+                       # Guess 'nearly' on musl systems.
+        *-musl*)       gl_cv_func_realpath_works="guessing nearly" ;;
+                       # Guess no on Cygwin.
+        cygwin*)       gl_cv_func_realpath_works="guessing no" ;;
                        # Guess no on native Windows.
         mingw*)        gl_cv_func_realpath_works="guessing no" ;;
                        # If we don't know, obey --enable-cross-guesses.
         *)             gl_cv_func_realpath_works="$gl_cross_guess_normal" ;;
       esac
      ])
-    rm -rf conftest.a conftest.d
+    rm -rf conftest.a conftest.l conftest.d
   ])
   case "$gl_cv_func_realpath_works" in
     *yes)
-      AC_DEFINE([FUNC_REALPATH_WORKS], [1], [Define to 1 if realpath()
-        can malloc memory, always gives an absolute path, and handles
-        trailing slash correctly.])
+      AC_DEFINE([FUNC_REALPATH_WORKS], [1],
+        [Define to 1 if realpath() can malloc memory, always gives an absolute path, and handles leading slashes and a trailing slash correctly.])
+      ;;
+    *nearly)
+      AC_DEFINE([FUNC_REALPATH_NEARLY_WORKS], [1],
+        [Define to 1 if realpath() can malloc memory, always gives an absolute path, and handles a trailing slash correctly.])
       ;;
   esac
 ])
diff --git a/m4/extensions.m4 b/m4/extensions.m4
index f7333acbd4f..5792a9557a8 100644
--- a/m4/extensions.m4
+++ b/m4/extensions.m4
@@ -1,4 +1,4 @@
-# serial 21  -*- Autoconf -*-
+# serial 22  -*- Autoconf -*-
 # Enable extensions on systems that normally disable them.
 
 # Copyright (C) 2003, 2006-2021 Free Software Foundation, Inc.
@@ -212,4 +212,16 @@ dnl it should only be defined when necessary.
 AC_DEFUN_ONCE([gl_USE_SYSTEM_EXTENSIONS],
 [
   AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
+
+  dnl On OpenBSD 6.8 with GCC, the include files contain a couple of
+  dnl definitions that are only activated with an explicit -D_ISOC11_SOURCE.
+  dnl That's because this version of GCC (4.2.1) supports the option
+  dnl '-std=gnu99' but not the option '-std=gnu11'.
+  AC_REQUIRE([AC_CANONICAL_HOST])
+  case "$host_os" in
+    openbsd*)
+      AC_DEFINE([_ISOC11_SOURCE], [1],
+        [Define to enable the declarations of ISO C 11 types and functions.])
+      ;;
+  esac
 ])
diff --git a/m4/fchmodat.m4 b/m4/fchmodat.m4
index 09380327799..66c0e308fcc 100644
--- a/m4/fchmodat.m4
+++ b/m4/fchmodat.m4
@@ -1,4 +1,4 @@
-# fchmodat.m4 serial 5
+# fchmodat.m4 serial 6
 dnl Copyright (C) 2004-2021 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -16,11 +16,9 @@ AC_DEFUN([gl_FUNC_FCHMODAT],
     HAVE_FCHMODAT=0
   else
     AC_CACHE_CHECK(
-      [whether fchmodat+AT_SYMLINK_NOFOLLOW works on non-symlinks],
+      [whether fchmodat works],
       [gl_cv_func_fchmodat_works],
-      [dnl This test fails on GNU/Linux with glibc 2.31 (but not on
-       dnl GNU/kFreeBSD nor GNU/Hurd) and Cygwin 2.9.
-       AC_RUN_IFELSE(
+      [AC_RUN_IFELSE(
          [AC_LANG_PROGRAM(
             [
               AC_INCLUDES_DEFAULT[
@@ -44,27 +42,49 @@ AC_DEFUN([gl_FUNC_FCHMODAT],
             [[
               int permissive = S_IRWXU | S_IRWXG | S_IRWXO;
               int desired = S_IRUSR | S_IWUSR;
-              static char const f[] = "conftest.fchmodat";
+              int result = 0;
+              #define file "conftest.fchmodat"
               struct stat st;
-              if (creat (f, permissive) < 0)
+              if (creat (file, permissive) < 0)
                 return 1;
-              if (fchmodat (AT_FDCWD, f, desired, AT_SYMLINK_NOFOLLOW) != 0)
+              /* Test whether fchmodat rejects a trailing slash on a non-directory.
+                 This test fails on AIX 7.2.  */
+              if (fchmodat (AT_FDCWD, file "/", desired, 0) == 0)
+                result |= 2;
+              /* Test whether fchmodat+AT_SYMLINK_NOFOLLOW works on non-symlinks.
+                 This test fails on GNU/Linux with glibc 2.31 (but not on
+                 GNU/kFreeBSD nor GNU/Hurd) and Cygwin 2.9.  */
+              if (fchmodat (AT_FDCWD, file, desired, AT_SYMLINK_NOFOLLOW) != 0)
+                result |= 4;
+              if (stat (file, &st) != 0)
                 return 1;
-              if (stat (f, &st) != 0)
-                return 1;
-              return ! ((st.st_mode & permissive) == desired);
+              if ((st.st_mode & permissive) != desired)
+                result |= 4;
+              return result;
             ]])],
          [gl_cv_func_fchmodat_works=yes],
-         [gl_cv_func_fchmodat_works=no],
+         [case $? in
+            2) gl_cv_func_fchmodat_works='nearly' ;;
+            *) gl_cv_func_fchmodat_works=no ;;
+          esac
+         ],
          [case "$host_os" in
-            dnl Guess no on Linux with glibc and Cygwin, yes otherwise.
+                                  # Guess no on Linux with glibc and Cygwin.
             linux-gnu* | cygwin*) gl_cv_func_fchmodat_works="guessing no" ;;
+                                  # Guess 'nearly' on AIX.
+            aix*)                 gl_cv_func_fchmodat_works="guessing nearly" ;;
+                                  # If we don't know, obey --enable-cross-guesses.
             *)                    gl_cv_func_fchmodat_works="$gl_cross_guess_normal" ;;
           esac
          ])
        rm -f conftest.fchmodat])
-    case $gl_cv_func_fchmodat_works in
+    case "$gl_cv_func_fchmodat_works" in
       *yes) ;;
+      *nearly)
+        AC_DEFINE([HAVE_NEARLY_WORKING_FCHMODAT], [1],
+          [Define to 1 if fchmodat works, except for the trailing slash handling.])
+        REPLACE_FCHMODAT=1
+        ;;
       *)
         AC_DEFINE([NEED_FCHMODAT_NONSYMLINK_FIX], [1],
           [Define to 1 if fchmodat+AT_SYMLINK_NOFOLLOW does not work right on non-symlinks.])
diff --git a/m4/gnulib-common.m4 b/m4/gnulib-common.m4
index 535359b2cf6..f2eff10de6d 100644
--- a/m4/gnulib-common.m4
+++ b/m4/gnulib-common.m4
@@ -39,11 +39,12 @@ AC_DEFUN([gl_COMMON_BODY], [
        this syntax with 'extern'.  */
 #  define _Noreturn [[noreturn]]
 # elif ((!defined __cplusplus || defined __clang__) \
-        && (201112 <= (defined __STDC_VERSION__ ? __STDC_VERSION__ : 0)  \
-            || _GL_GNUC_PREREQ (4, 7) \
-            || (defined __apple_build_version__ \
-                ? 6000000 <= __apple_build_version__ \
-                : 3 < __clang_major__ + (5 <= __clang_minor__))))
+        && (201112 <= (defined __STDC_VERSION__ ? __STDC_VERSION__ : 0) \
+            || (!defined __STRICT_ANSI__ \
+                && (_GL_GNUC_PREREQ (4, 7) \
+                    || (defined __apple_build_version__ \
+                        ? 6000000 <= __apple_build_version__ \
+                        : 3 < __clang_major__ + (5 <= __clang_minor__))))))
    /* _Noreturn works as-is.  */
 # elif _GL_GNUC_PREREQ (2, 8) || defined __clang__ || 0x5110 <= __SUNPRO_C
 #  define _Noreturn __attribute__ ((__noreturn__))
@@ -66,7 +67,9 @@ AC_DEFUN([gl_COMMON_BODY], [
 #endif])
   AH_VERBATIM([attribute],
 [/* Attributes.  */
-#ifdef __has_attribute
+#if (defined __has_attribute \
+     && (!defined __clang_minor__ \
+         || 3 < __clang_major__ + (5 <= __clang_minor__)))
 # define _GL_HAS_ATTRIBUTE(attr) __has_attribute (__##attr##__)
 #else
 # define _GL_HAS_ATTRIBUTE(attr) _GL_ATTR_##attr
diff --git a/m4/gnulib-comp.m4 b/m4/gnulib-comp.m4
index ad109520dd1..cd6f7b4bbdf 100644
--- a/m4/gnulib-comp.m4
+++ b/m4/gnulib-comp.m4
@@ -75,6 +75,7 @@ AC_DEFUN([gl_EARLY],
   # Code from module dtoastr:
   # Code from module dtotimespec:
   # Code from module dup2:
+  # Code from module dynarray:
   # Code from module eloop-threshold:
   # Code from module environ:
   # Code from module errno:
@@ -517,6 +518,7 @@ AC_DEFUN([gl_INIT],
   gl_gnulib_enabled_260941c0e5dc67ec9e87d1fb321c300b=false
   gl_gnulib_enabled_cloexec=false
   gl_gnulib_enabled_dirfd=false
+  gl_gnulib_enabled_dynarray=false
   gl_gnulib_enabled_925677f0343de64b89a9f0c790b4104c=false
   gl_gnulib_enabled_euidaccess=false
   gl_gnulib_enabled_getdtablesize=false
@@ -564,6 +566,12 @@ AC_DEFUN([gl_INIT],
       gl_gnulib_enabled_dirfd=true
     fi
   }
+  func_gl_gnulib_m4code_dynarray ()
+  {
+    if ! $gl_gnulib_enabled_dynarray; then
+      gl_gnulib_enabled_dynarray=true
+    fi
+  }
   func_gl_gnulib_m4code_925677f0343de64b89a9f0c790b4104c ()
   {
     if ! $gl_gnulib_enabled_925677f0343de64b89a9f0c790b4104c; then
@@ -797,6 +805,9 @@ AC_DEFUN([gl_INIT],
   if test $HAVE_READLINKAT = 0 || test $REPLACE_READLINKAT = 1; then
     func_gl_gnulib_m4code_03e0aaad4cb89ca757653bd367a6ccb7
   fi
+  if test $ac_use_included_regex = yes; then
+    func_gl_gnulib_m4code_dynarray
+  fi
   if { test $HAVE_DECL_STRTOIMAX = 0 || test $REPLACE_STRTOIMAX = 1; } && test $ac_cv_type_long_long_int = yes; then
     func_gl_gnulib_m4code_strtoll
   fi
@@ -819,6 +830,7 @@ AC_DEFUN([gl_INIT],
   AM_CONDITIONAL([gl_GNULIB_ENABLED_260941c0e5dc67ec9e87d1fb321c300b], [$gl_gnulib_enabled_260941c0e5dc67ec9e87d1fb321c300b])
   AM_CONDITIONAL([gl_GNULIB_ENABLED_cloexec], [$gl_gnulib_enabled_cloexec])
   AM_CONDITIONAL([gl_GNULIB_ENABLED_dirfd], [$gl_gnulib_enabled_dirfd])
+  AM_CONDITIONAL([gl_GNULIB_ENABLED_dynarray], [$gl_gnulib_enabled_dynarray])
   AM_CONDITIONAL([gl_GNULIB_ENABLED_925677f0343de64b89a9f0c790b4104c], [$gl_gnulib_enabled_925677f0343de64b89a9f0c790b4104c])
   AM_CONDITIONAL([gl_GNULIB_ENABLED_euidaccess], [$gl_gnulib_enabled_euidaccess])
   AM_CONDITIONAL([gl_GNULIB_ENABLED_getdtablesize], [$gl_gnulib_enabled_getdtablesize])
@@ -1021,6 +1033,7 @@ AC_DEFUN([gl_FILE_LIST], [
   lib/dtoastr.c
   lib/dtotimespec.c
   lib/dup2.c
+  lib/dynarray.h
   lib/eloop-threshold.h
   lib/errno.in.h
   lib/euidaccess.c
@@ -1076,6 +1089,13 @@ AC_DEFUN([gl_FILE_LIST], [
   lib/libc-config.h
   lib/limits.in.h
   lib/lstat.c
+  lib/malloc/dynarray-skeleton.c
+  lib/malloc/dynarray.h
+  lib/malloc/dynarray_at_failure.c
+  lib/malloc/dynarray_emplace_enlarge.c
+  lib/malloc/dynarray_finalize.c
+  lib/malloc/dynarray_resize.c
+  lib/malloc/dynarray_resize_clear.c
   lib/malloc/scratch_buffer.h
   lib/malloc/scratch_buffer_dupfree.c
   lib/malloc/scratch_buffer_grow.c
diff --git a/m4/nstrftime.m4 b/m4/nstrftime.m4
index 4674442810b..b510554b947 100644
--- a/m4/nstrftime.m4
+++ b/m4/nstrftime.m4
@@ -1,4 +1,4 @@
-# serial 36
+# serial 37
 
 # Copyright (C) 1996-1997, 1999-2007, 2009-2021 Free Software Foundation, Inc.
 #
@@ -12,7 +12,7 @@ AC_DEFUN([gl_FUNC_GNU_STRFTIME],
 [
  AC_REQUIRE([AC_C_RESTRICT])
 
- # This defines (or not) HAVE_TZNAME and HAVE_TM_ZONE.
+ # This defines (or not) HAVE_TZNAME and HAVE_STRUCT_TM_TM_ZONE.
  AC_REQUIRE([AC_STRUCT_TIMEZONE])
 
  AC_REQUIRE([gl_TM_GMTOFF])
diff --git a/m4/stddef_h.m4 b/m4/stddef_h.m4
index 18e872f483e..cd666c4a58c 100644
--- a/m4/stddef_h.m4
+++ b/m4/stddef_h.m4
@@ -1,14 +1,19 @@
-dnl A placeholder for <stddef.h>, for platforms that have issues.
-# stddef_h.m4 serial 7
+# stddef_h.m4 serial 9
 dnl Copyright (C) 2009-2021 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
 
+dnl A placeholder for <stddef.h>, for platforms that have issues.
+
 AC_DEFUN([gl_STDDEF_H],
 [
   AC_REQUIRE([gl_STDDEF_H_DEFAULTS])
   AC_REQUIRE([gt_TYPE_WCHAR_T])
+
+  dnl Persuade OpenBSD <stddef.h> to declare max_align_t.
+  AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
+
   STDDEF_H=
 
   dnl Test whether the type max_align_t exists and whether its alignment
@@ -23,6 +28,13 @@ AC_DEFUN([gl_STDDEF_H],
             int check1[2 * (__alignof__ (double) <= __alignof__ (max_align_t)) - 1];
             int check2[2 * (__alignof__ (long double) <= __alignof__ (max_align_t)) - 1];
             #endif
+            typedef struct { char a; max_align_t b; } max_helper;
+            typedef struct { char a; long b; } long_helper;
+            typedef struct { char a; double b; } double_helper;
+            typedef struct { char a; long double b; } long_double_helper;
+            int check3[2 * (offsetof (long_helper, b) <= offsetof (max_helper, b)) - 1];
+            int check4[2 * (offsetof (double_helper, b) <= offsetof (max_helper, b)) - 1];
+            int check5[2 * (offsetof (long_double_helper, b) <= offsetof (max_helper, b)) - 1];
           ]])],
        [gl_cv_type_max_align_t=yes],
        [gl_cv_type_max_align_t=no])
diff --git a/m4/string_h.m4 b/m4/string_h.m4
index 3e65355735c..a4cc5b43783 100644
--- a/m4/string_h.m4
+++ b/m4/string_h.m4
@@ -5,7 +5,7 @@
 # gives unlimited permission to copy and/or distribute it,
 # with or without modifications, as long as this notice is preserved.
 
-# serial 28
+# serial 29
 
 # Written by Paul Eggert.
 
@@ -113,6 +113,7 @@ AC_DEFUN([gl_HEADER_STRING_H_DEFAULTS],
   HAVE_SIGDESCR_NP=1;           AC_SUBST([HAVE_SIGDESCR_NP])
   HAVE_DECL_STRSIGNAL=1;        AC_SUBST([HAVE_DECL_STRSIGNAL])
   HAVE_STRVERSCMP=1;            AC_SUBST([HAVE_STRVERSCMP])
+  REPLACE_FFSLL=0;              AC_SUBST([REPLACE_FFSLL])
   REPLACE_MEMCHR=0;             AC_SUBST([REPLACE_MEMCHR])
   REPLACE_MEMMEM=0;             AC_SUBST([REPLACE_MEMMEM])
   REPLACE_STPNCPY=0;            AC_SUBST([REPLACE_STPNCPY])
diff --git a/m4/sys_stat_h.m4 b/m4/sys_stat_h.m4
index e8eac71b466..23cbdd28eb2 100644
--- a/m4/sys_stat_h.m4
+++ b/m4/sys_stat_h.m4
@@ -1,4 +1,4 @@
-# sys_stat_h.m4 serial 36   -*- Autoconf -*-
+# sys_stat_h.m4 serial 38   -*- Autoconf -*-
 dnl Copyright (C) 2006-2021 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -104,7 +104,9 @@ AC_DEFUN([gl_SYS_STAT_H_DEFAULTS],
   REPLACE_LSTAT=0;      AC_SUBST([REPLACE_LSTAT])
   REPLACE_MKDIR=0;      AC_SUBST([REPLACE_MKDIR])
   REPLACE_MKFIFO=0;     AC_SUBST([REPLACE_MKFIFO])
+  REPLACE_MKFIFOAT=0;   AC_SUBST([REPLACE_MKFIFOAT])
   REPLACE_MKNOD=0;      AC_SUBST([REPLACE_MKNOD])
+  REPLACE_MKNODAT=0;    AC_SUBST([REPLACE_MKNODAT])
   REPLACE_STAT=0;       AC_SUBST([REPLACE_STAT])
   REPLACE_UTIMENSAT=0;  AC_SUBST([REPLACE_UTIMENSAT])
 ])
diff --git a/m4/time_h.m4 b/m4/time_h.m4
index 07e6967e45b..b6a1aa3bc0f 100644
--- a/m4/time_h.m4
+++ b/m4/time_h.m4
@@ -2,7 +2,7 @@
 
 # Copyright (C) 2000-2001, 2003-2007, 2009-2021 Free Software Foundation, Inc.
 
-# serial 13
+# serial 15
 
 # This file is free software; the Free Software Foundation
 # gives unlimited permission to copy and/or distribute it,
@@ -25,6 +25,22 @@ AC_DEFUN([gl_HEADER_TIME_H_BODY],
   AC_REQUIRE([gl_CHECK_TYPE_STRUCT_TIMESPEC])
 
   AC_REQUIRE([AC_C_RESTRICT])
+
+  AC_CACHE_CHECK([for TIME_UTC in <time.h>],
+    [gl_cv_time_h_has_TIME_UTC],
+    [AC_COMPILE_IFELSE(
+       [AC_LANG_PROGRAM(
+          [[#include <time.h>
+          ]],
+          [[static int x = TIME_UTC; x++;]])],
+       [gl_cv_time_h_has_TIME_UTC=yes],
+       [gl_cv_time_h_has_TIME_UTC=no])])
+  if test $gl_cv_time_h_has_TIME_UTC = yes; then
+    TIME_H_DEFINES_TIME_UTC=1
+  else
+    TIME_H_DEFINES_TIME_UTC=0
+  fi
+  AC_SUBST([TIME_H_DEFINES_TIME_UTC])
 ])
 
 dnl Check whether 'struct timespec' is declared
@@ -113,6 +129,7 @@ AC_DEFUN([gl_HEADER_TIME_H_DEFAULTS],
   GNULIB_STRFTIME=0;                     AC_SUBST([GNULIB_STRFTIME])
   GNULIB_STRPTIME=0;                     AC_SUBST([GNULIB_STRPTIME])
   GNULIB_TIMEGM=0;                       AC_SUBST([GNULIB_TIMEGM])
+  GNULIB_TIMESPEC_GET=0;                 AC_SUBST([GNULIB_TIMESPEC_GET])
   GNULIB_TIME_R=0;                       AC_SUBST([GNULIB_TIME_R])
   GNULIB_TIME_RZ=0;                      AC_SUBST([GNULIB_TIME_RZ])
   GNULIB_TZSET=0;                        AC_SUBST([GNULIB_TZSET])
@@ -123,6 +140,7 @@ AC_DEFUN([gl_HEADER_TIME_H_DEFAULTS],
   HAVE_NANOSLEEP=1;                      AC_SUBST([HAVE_NANOSLEEP])
   HAVE_STRPTIME=1;                       AC_SUBST([HAVE_STRPTIME])
   HAVE_TIMEGM=1;                         AC_SUBST([HAVE_TIMEGM])
+  HAVE_TIMESPEC_GET=1;                   AC_SUBST([HAVE_TIMESPEC_GET])
   dnl Even GNU libc does not have timezone_t yet.
   HAVE_TIMEZONE_T=0;                     AC_SUBST([HAVE_TIMEZONE_T])
   dnl If another module says to replace or to not replace, do that.
diff --git a/m4/utimensat.m4 b/m4/utimensat.m4
index bdabe24c568..b5bff1651f3 100644
--- a/m4/utimensat.m4
+++ b/m4/utimensat.m4
@@ -1,4 +1,4 @@
-# serial 7
+# serial 9
 # See if we need to provide utimensat replacement.
 
 dnl Copyright (C) 2009-2021 Free Software Foundation, Inc.
@@ -12,6 +12,7 @@ AC_DEFUN([gl_FUNC_UTIMENSAT],
 [
   AC_REQUIRE([gl_SYS_STAT_H_DEFAULTS])
   AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
   AC_CHECK_FUNCS_ONCE([utimensat])
   if test $ac_cv_func_utimensat = no; then
     HAVE_UTIMENSAT=0
@@ -28,10 +29,19 @@ AC_DEFUN([gl_FUNC_UTIMENSAT],
               const char *f = "conftest.file";
               if (close (creat (f, 0600)))
                 return 1;
+              /* Test whether a trailing slash is handled correctly.
+                 This fails on AIX 7.2.  */
+              {
+                struct timespec ts[2];
+                ts[0].tv_sec = 345183300; ts[0].tv_nsec = 0;
+                ts[1] = ts[0];
+                if (utimensat (AT_FDCWD, "conftest.file/", ts, 0) == 0)
+                  result |= 2;
+              }
               /* Test whether the AT_SYMLINK_NOFOLLOW flag is supported.  */
               {
                 if (utimensat (AT_FDCWD, f, NULL, AT_SYMLINK_NOFOLLOW))
-                  result |= 2;
+                  result |= 4;
               }
               /* Test whether UTIME_NOW and UTIME_OMIT work.  */
               {
@@ -41,7 +51,7 @@ AC_DEFUN([gl_FUNC_UTIMENSAT],
                 ts[1].tv_sec = 1;
                 ts[1].tv_nsec = UTIME_NOW;
                 if (utimensat (AT_FDCWD, f, ts, 0))
-                  result |= 4;
+                  result |= 8;
               }
               sleep (1);
               {
@@ -52,19 +62,44 @@ AC_DEFUN([gl_FUNC_UTIMENSAT],
                 ts[1].tv_sec = 1;
                 ts[1].tv_nsec = UTIME_OMIT;
                 if (utimensat (AT_FDCWD, f, ts, 0))
-                  result |= 8;
-                if (stat (f, &st))
                   result |= 16;
-                else if (st.st_ctime < st.st_atime)
+                if (stat (f, &st))
                   result |= 32;
+                else if (st.st_ctime < st.st_atime)
+                  result |= 64;
               }
               return result;
             ]])],
          [gl_cv_func_utimensat_works=yes],
-         [gl_cv_func_utimensat_works=no],
-         [gl_cv_func_utimensat_works="guessing yes"])])
-    if test "$gl_cv_func_utimensat_works" = no; then
-      REPLACE_UTIMENSAT=1
-    fi
+         [case $? in
+            2) gl_cv_func_utimensat_works='nearly' ;;
+            *) gl_cv_func_utimensat_works=no ;;
+          esac
+         ],
+         [case "$host_os" in
+            # Guess yes on Linux or glibc systems.
+            linux-* | linux | *-gnu* | gnu*)
+              gl_cv_func_utimensat_works="guessing yes" ;;
+            # Guess 'nearly' on AIX.
+            aix*)
+              gl_cv_func_utimensat_works="guessing nearly" ;;
+            # If we don't know, obey --enable-cross-guesses.
+            *)
+              gl_cv_func_utimensat_works="$gl_cross_guess_normal" ;;
+          esac
+         ])
+      ])
+    case "$gl_cv_func_utimensat_works" in
+      *yes)
+        ;;
+      *nearly)
+        AC_DEFINE([HAVE_NEARLY_WORKING_UTIMENSAT], [1],
+          [Define to 1 if utimensat works, except for the trailing slash handling.])
+        REPLACE_UTIMENSAT=1
+        ;;
+      *)
+        REPLACE_UTIMENSAT=1
+        ;;
+    esac
   fi
 ])
diff --git a/src/alloc.c b/src/alloc.c
index 350fec25a02..0ed5b9346f6 100644
--- a/src/alloc.c
+++ b/src/alloc.c
@@ -6122,11 +6122,13 @@ garbage_collect (void)
 
   gc_in_progress = 0;
 
-  unblock_input ();
-
   consing_until_gc = gc_threshold
     = consing_threshold (gc_cons_threshold, Vgc_cons_percentage, 0);
 
+  /* Unblock *after* re-setting `consing_until_gc` in case `unblock_input`
+     signals an error (see bug#43389).  */
+  unblock_input ();
+
   if (garbage_collection_messages && NILP (Vmemory_full))
     {
       if (message_p || minibuf_level > 0)
diff --git a/src/conf_post.h b/src/conf_post.h
index bd56f29e287..176ab28b21a 100644
--- a/src/conf_post.h
+++ b/src/conf_post.h
@@ -71,7 +71,9 @@ typedef bool bool_bf;
    It is used only on arguments like cleanup that are handled here.
    This macro should be used only in #if expressions, as Oracle
    Studio 12.5's __has_attribute does not work in plain code.  */
-#ifdef __has_attribute
+#if (defined __has_attribute \
+     && (!defined __clang_minor__ \
+         || 3 < __clang_major__ + (5 <= __clang_minor__)))
 # define HAS_ATTRIBUTE(a) __has_attribute (__##a##__)
 #else
 # define HAS_ATTRIBUTE(a) HAS_ATTR_##a
diff --git a/src/emacs-module.h.in b/src/emacs-module.h.in
index 2989b439109..fe52587c1a5 100644
--- a/src/emacs-module.h.in
+++ b/src/emacs-module.h.in
@@ -51,7 +51,9 @@ information how to write modules and use this header file.
 #if 3 < __GNUC__ + (3 <= __GNUC_MINOR__)
 # define EMACS_ATTRIBUTE_NONNULL(...) \
    __attribute__ ((__nonnull__ (__VA_ARGS__)))
-#elif defined __has_attribute
+#elif (defined __has_attribute \
+       && (!defined __clang_minor__ \
+           || 3 < __clang_major__ + (5 <= __clang_minor__)))
 # if __has_attribute (__nonnull__)
 #  define EMACS_ATTRIBUTE_NONNULL(...) \
     __attribute__ ((__nonnull__ (__VA_ARGS__)))
diff --git a/src/frame.c b/src/frame.c
index 45ee96e9620..599c4075f88 100644
--- a/src/frame.c
+++ b/src/frame.c
@@ -2572,23 +2572,30 @@ before calling this function on it, like this.
   int yval = check_integer_range (y, INT_MIN, INT_MAX);
 
   /* I think this should be done with a hook.  */
-#ifdef HAVE_WINDOW_SYSTEM
   if (FRAME_WINDOW_P (XFRAME (frame)))
-    /* Warping the mouse will cause enternotify and focus events.  */
-    frame_set_mouse_position (XFRAME (frame), xval, yval);
-#elif defined MSDOS
-  if (FRAME_MSDOS_P (XFRAME (frame)))
+    {
+#ifdef HAVE_WINDOW_SYSTEM
+      /* Warping the mouse will cause enternotify and focus events.  */
+      frame_set_mouse_position (XFRAME (frame), xval, yval);
+#endif /* HAVE_WINDOW_SYSTEM */
+    }
+#ifdef MSDOS
+  else if (FRAME_MSDOS_P (XFRAME (frame)))
     {
       Fselect_frame (frame, Qnil);
       mouse_moveto (xval, yval);
     }
-#elif defined HAVE_GPM
-  Fselect_frame (frame, Qnil);
-  term_mouse_moveto (xval, yval);
+#endif /* MSDOS */
+  else
+    {
+      Fselect_frame (frame, Qnil);
+#ifdef HAVE_GPM
+      term_mouse_moveto (xval, yval);
 #else
-  (void) xval;
-  (void) yval;
-#endif
+      (void) xval;
+      (void) yval;
+#endif /* HAVE_GPM */
+    }
 
   return Qnil;
 }
@@ -2610,23 +2617,31 @@ before calling this function on it, like this.
   int yval = check_integer_range (y, INT_MIN, INT_MAX);
 
   /* I think this should be done with a hook.  */
-#ifdef HAVE_WINDOW_SYSTEM
   if (FRAME_WINDOW_P (XFRAME (frame)))
-    /* Warping the mouse will cause enternotify and focus events.  */
-    frame_set_mouse_pixel_position (XFRAME (frame), xval, yval);
-#elif defined MSDOS
-  if (FRAME_MSDOS_P (XFRAME (frame)))
+    {
+      /* Warping the mouse will cause enternotify and focus events.  */
+#ifdef HAVE_WINDOW_SYSTEM
+      frame_set_mouse_pixel_position (XFRAME (frame), xval, yval);
+#endif /* HAVE_WINDOW_SYSTEM */
+    }
+#ifdef MSDOS
+  else if (FRAME_MSDOS_P (XFRAME (frame)))
     {
       Fselect_frame (frame, Qnil);
       mouse_moveto (xval, yval);
     }
-#elif defined HAVE_GPM
-  Fselect_frame (frame, Qnil);
-  term_mouse_moveto (xval, yval);
+#endif /* MSDOS */
+  else
+    {
+      Fselect_frame (frame, Qnil);
+#ifdef HAVE_GPM
+      term_mouse_moveto (xval, yval);
 #else
-  (void) xval;
-  (void) yval;
-#endif
+      (void) xval;
+      (void) yval;
+#endif /* HAVE_GPM */
+
+    }
 
   return Qnil;
 }
diff --git a/src/nsfns.m b/src/nsfns.m
index ae114f83e4d..24ea7d7f63b 100644
--- a/src/nsfns.m
+++ b/src/nsfns.m
@@ -1487,7 +1487,6 @@ Some window managers may refuse to restack windows.  */)
     {
       EmacsWindow *window = (EmacsWindow *)[FRAME_NS_VIEW (f1) window];
       NSWindow *window2 = [FRAME_NS_VIEW (f2) window];
-      BOOL flag = !NILP (above);
 
       if ([window restackWindow:window2 above:!NILP (above)])
         return Qt;
diff --git a/src/nsmenu.m b/src/nsmenu.m
index 8086f56854e..f8219d27026 100644
--- a/src/nsmenu.m
+++ b/src/nsmenu.m
@@ -101,7 +101,6 @@ popup_activated (void)
 static void
 ns_update_menubar (struct frame *f, bool deep_p)
 {
-  NSAutoreleasePool *pool;
   BOOL needsSet = NO;
   id menu = [NSApp mainMenu];
   bool owfi;
diff --git a/src/nsselect.m b/src/nsselect.m
index 27db9248e46..5ab3ef77fec 100644
--- a/src/nsselect.m
+++ b/src/nsselect.m
@@ -78,7 +78,13 @@ ns_string_to_symbol (NSString *t)
     return QSECONDARY;
   if ([t isEqualToString: NSPasteboardTypeString])
     return QTEXT;
-  if ([t isEqualToString: NSFilenamesPboardType])
+  if ([t isEqualToString:
+#if NS_USE_NSPasteboardTypeFileURL != 0
+           NSPasteboardTypeFileURL
+#else
+           NSFilenamesPboardType
+#endif
+       ])
     return QFILE_NAME;
   if ([t isEqualToString: NSPasteboardTypeTabularText])
     return QTEXT;
@@ -467,7 +473,12 @@ nxatoms_of_nsselect (void)
              [NSNumber numberWithLong:0], NXPrimaryPboard,
              [NSNumber numberWithLong:0], NXSecondaryPboard,
              [NSNumber numberWithLong:0], NSPasteboardTypeString,
-             [NSNumber numberWithLong:0], NSFilenamesPboardType,
+             [NSNumber numberWithLong:0],
+#if NS_USE_NSPasteboardTypeFileURL != 0
+                                          NSPasteboardTypeFileURL,
+#else
+                                          NSFilenamesPboardType,
+#endif
              [NSNumber numberWithLong:0], NSPasteboardTypeTabularText,
          nil] retain];
 }
diff --git a/src/nsterm.h b/src/nsterm.h
index 2c9d8e85ba9..eae1d0725ea 100644
--- a/src/nsterm.h
+++ b/src/nsterm.h
@@ -39,6 +39,15 @@ typedef CGFloat EmacsCGFloat;
 typedef float EmacsCGFloat;
 #endif
 
+/* NSFilenamesPboardType is deprecated in macOS 10.14, but
+   NSPasteboardTypeFileURL is only available in 10.13 (and GNUstep
+   probably lacks it too). */
+#if defined NS_IMPL_COCOA && MAC_OS_X_VERSION_MIN_REQUIRED >= 101300
+#define NS_USE_NSPasteboardTypeFileURL 1
+#else
+#define NS_USE_NSPasteboardTypeFileURL 0
+#endif
+
 /* ==========================================================================
 
    Trace support
diff --git a/src/nsterm.m b/src/nsterm.m
index 2defb9e2eec..df3934c5c34 100644
--- a/src/nsterm.m
+++ b/src/nsterm.m
@@ -272,7 +272,9 @@ long context_menu_value = 0;
 
 /* display update */
 static struct frame *ns_updating_frame;
+#if !defined (NS_DRAW_TO_BUFFER) || MAC_OS_X_VERSION_MIN_REQUIRED < 101400
 static NSView *focus_view = NULL;
+#endif
 static int ns_window_num = 0;
 static BOOL gsaved = NO;
 static BOOL ns_fake_keydown = NO;
@@ -1139,7 +1141,9 @@ ns_update_end (struct frame *f)
    external (RIF) call; for whole frame, called after gui_update_window_end
    -------------------------------------------------------------------------- */
 {
+#if !defined (NS_DRAW_TO_BUFFER) || MAC_OS_X_VERSION_MIN_REQUIRED < 101400
   EmacsView *view = FRAME_NS_VIEW (f);
+#endif
 
   NSTRACE_WHEN (NSTRACE_GROUP_UPDATES, "ns_update_end");
 
@@ -1449,7 +1453,7 @@ ns_ring_bell (struct frame *f)
     }
 }
 
-
+#if !defined (NS_DRAW_TO_BUFFER) || MAC_OS_X_VERSION_MIN_REQUIRED < 101400
 static void
 hide_bell (void)
 /* --------------------------------------------------------------------------
@@ -1463,6 +1467,7 @@ hide_bell (void)
       [bell_view remove];
     }
 }
+#endif
 
 
 /* ==========================================================================
@@ -2876,6 +2881,8 @@ ns_get_shifted_character (NSEvent *event)
    ========================================================================== */
 
 
+#if 0
+/* FIXME: Remove this function. */
 static void
 ns_redraw_scroll_bars (struct frame *f)
 {
@@ -2890,6 +2897,7 @@ ns_redraw_scroll_bars (struct frame *f)
       [view display];
     }
 }
+#endif
 
 
 void
@@ -5602,7 +5610,11 @@ ns_term_init (Lisp_Object display_name)
   ns_drag_types = [[NSArray arrayWithObjects:
                             NSPasteboardTypeString,
                             NSPasteboardTypeTabularText,
+#if NS_USE_NSPasteboardTypeFileURL != 0
+                            NSPasteboardTypeFileURL,
+#else
                             NSFilenamesPboardType,
+#endif
                             NSPasteboardTypeURL, nil] retain];
 
   /* If fullscreen is in init/default-frame-alist, focus isn't set
@@ -8395,21 +8407,23 @@ not_in_argv (NSString *arg)
       void *pixels = CGBitmapContextGetData (context);
       int rowSize = CGBitmapContextGetBytesPerRow (context);
       int srcRowSize = NSWidth (srcRect) * scale * bpp;
-      void *srcPixels = pixels + (int)(NSMinY (srcRect) * scale * rowSize
-                                       + NSMinX (srcRect) * scale * bpp);
-      void *dstPixels = pixels + (int)(NSMinY (dstRect) * scale * rowSize
-                                       + NSMinX (dstRect) * scale * bpp);
+      void *srcPixels = (char *) pixels
+                        + (int) (NSMinY (srcRect) * scale * rowSize
+                                 + NSMinX (srcRect) * scale * bpp);
+      void *dstPixels = (char *) pixels
+                        + (int) (NSMinY (dstRect) * scale * rowSize
+                                 + NSMinX (dstRect) * scale * bpp);
 
       if (NSIntersectsRect (srcRect, dstRect)
           && NSMinY (srcRect) < NSMinY (dstRect))
         for (int y = NSHeight (srcRect) * scale - 1 ; y >= 0 ; y--)
-          memmove (dstPixels + y * rowSize,
-                   srcPixels + y * rowSize,
+          memmove ((char *) dstPixels + y * rowSize,
+                   (char *) srcPixels + y * rowSize,
                    srcRowSize);
       else
         for (int y = 0 ; y < NSHeight (srcRect) * scale ; y++)
-          memmove (dstPixels + y * rowSize,
-                   srcPixels + y * rowSize,
+          memmove ((char *) dstPixels + y * rowSize,
+                   (char *) srcPixels + y * rowSize,
                    srcRowSize);
 
 #if MAC_OS_X_VERSION_MIN_REQUIRED < 101400
@@ -8533,9 +8547,19 @@ not_in_argv (NSString *arg)
     {
       return NO;
     }
-  /* FIXME: NSFilenamesPboardType is deprecated in 10.14, but the
-     NSURL method can only handle one file at a time.  Stick with the
-     existing code at the moment.  */
+#if NS_USE_NSPasteboardTypeFileURL != 0
+  else if ([type isEqualToString: NSPasteboardTypeFileURL])
+    {
+      type_sym = Qfile;
+
+      NSArray *urls = [pb readObjectsForClasses: @[[NSURL self]]
+                                        options: nil];
+      NSEnumerator *uenum = [urls objectEnumerator];
+      NSURL *url;
+      while ((url = [uenum nextObject]))
+        strings = Fcons ([[url path] lispString], strings);
+    }
+#else  // !NS_USE_NSPasteboardTypeFileURL
   else if ([type isEqualToString: NSFilenamesPboardType])
     {
       NSArray *files;
@@ -8551,6 +8575,7 @@ not_in_argv (NSString *arg)
       while ( (file = [fenum nextObject]) )
         strings = Fcons ([file lispString], strings);
     }
+#endif   // !NS_USE_NSPasteboardTypeFileURL
   else if ([type isEqualToString: NSPasteboardTypeURL])
     {
       NSURL *url = [NSURL URLFromPasteboard: pb];
@@ -8727,7 +8752,8 @@ not_in_argv (NSString *arg)
 /* The array returned by [NSWindow parentWindow] may already be
    sorted, but the documentation doesn't tell us whether or not it is,
    so to be safe we'll sort it.  */
-NSInteger nswindow_orderedIndex_sort (id w1, id w2, void *c)
+static NSInteger
+nswindow_orderedIndex_sort (id w1, id w2, void *c)
 {
   NSInteger i1 = [w1 orderedIndex];
   NSInteger i2 = [w2 orderedIndex];
diff --git a/src/process.c b/src/process.c
index dac7d0440fa..1df4ed9ce03 100644
--- a/src/process.c
+++ b/src/process.c
@@ -283,6 +283,18 @@ static int max_desc;
    the file descriptor of a socket that is already bound.  */
 static int external_sock_fd;
 
+/* File descriptor that becomes readable when we receive SIGCHLD.  */
+static int child_signal_read_fd = -1;
+/* The write end thereof.  The SIGCHLD handler writes to this file
+   descriptor to notify `wait_reading_process_output' of process
+   status changes.  */
+static int child_signal_write_fd = -1;
+static void child_signal_init (void);
+#ifndef WINDOWSNT
+static void child_signal_read (int, void *);
+#endif
+static void child_signal_notify (void);
+
 /* Indexed by descriptor, gives the process (if any) for that descriptor.  */
 static Lisp_Object chan_process[FD_SETSIZE];
 static void wait_for_socket_fds (Lisp_Object, char const *);
@@ -2060,6 +2072,10 @@ create_process (Lisp_Object process, char **new_argv, Lisp_Object current_dir)
   Lisp_Object lisp_pty_name = Qnil;
   sigset_t oldset;
 
+  /* Ensure that the SIGCHLD handler can notify
+     `wait_reading_process_output'.  */
+  child_signal_init ();
+
   inchannel = outchannel = -1;
 
   if (p->pty_flag)
@@ -5309,6 +5325,15 @@ wait_reading_process_output (intmax_t time_limit, int nsecs, int read_kbd,
             compute_input_wait_mask (&Atemp);
           compute_write_mask (&Ctemp);
 
+          /* If a process status has changed, the child signal pipe
+             will likely be readable.  We want to ignore it for now,
+             because otherwise we wouldn't run into a timeout
+             below.  */
+          int fd = child_signal_read_fd;
+          eassert (fd < FD_SETSIZE);
+          if (0 <= fd)
+            FD_CLR (fd, &Atemp);
+
           timeout = make_timespec (0, 0);
           if ((thread_select (pselect, max_desc + 1,
                               &Atemp,
@@ -5395,6 +5420,14 @@ wait_reading_process_output (intmax_t time_limit, int nsecs, int read_kbd,
           check_write = true;
         }
 
+      /* We have to be informed when we receive a SIGCHLD signal for
+         an asynchronous process.  Otherwise this might deadlock if we
+         receive a SIGCHLD during `pselect'.  */
+      int child_fd = child_signal_read_fd;
+      eassert (child_fd < FD_SETSIZE);
+      if (0 <= child_fd)
+        FD_SET (child_fd, &Available);
+
       /* If frame size has changed or the window is newly mapped,
          redisplay now, before we start to wait.  There is a race
          condition here; if a SIGIO arrives between now and the select
@@ -7114,7 +7147,95 @@ process has been transmitted to the serial port.  */)
    subprocesses which the main thread should not reap.  For example,
    if the main thread attempted to reap an already-reaped child, it
    might inadvertently reap a GTK-created process that happened to
-   have the same process ID.  */
+   have the same process ID.
+
+   To avoid a deadlock when receiving SIGCHLD while
+   'wait_reading_process_output' is in 'pselect', the SIGCHLD handler
+   will notify the `pselect' using a self-pipe.  The deadlock could
+   occur if SIGCHLD is delivered outside of the 'pselect' call, in
+   which case 'pselect' will not be interrupted by the signal, and
+   will therefore wait on the process's output descriptor for the
+   output that will never come.
+
+   WINDOWSNT doesn't need this facility because its 'pselect'
+   emulation (see 'sys_select' in w32proc.c) waits on a subprocess
+   handle, which becomes signaled when the process exits, and also
+   because that emulation delays the delivery of the simulated SIGCHLD
+   until all the output from the subprocess has been consumed.  */
+
+/* FIXME: On Unix-like systems that have a proper 'pselect'
+   (HAVE_PSELECT), we should block SIGCHLD in
+   'wait_reading_process_output' and pass a non-NULL signal mask to
+   'pselect' to avoid the need for the self-pipe.  */
+
+/* Set up `child_signal_read_fd' and `child_signal_write_fd'.  */
+
+static void
+child_signal_init (void)
+{
+  /* Either both are initialized, or both are uninitialized.  */
+  eassert ((child_signal_read_fd < 0) == (child_signal_write_fd < 0));
+
+#ifndef WINDOWSNT
+  if (0 <= child_signal_read_fd)
+    return; /* already done */
+
+  int fds[2];
+  if (emacs_pipe (fds) < 0)
+    report_file_error ("Creating pipe for child signal", Qnil);
+  if (FD_SETSIZE <= fds[0])
+    {
+      /* Since we need to `pselect' on the read end, it has to fit
+         into an `fd_set'.  */
+      emacs_close (fds[0]);
+      emacs_close (fds[1]);
+      report_file_errno ("Creating pipe for child signal", Qnil,
+                         EMFILE);
+    }
+
+  /* We leave the file descriptors open until the Emacs process
+     exits.  */
+  eassert (0 <= fds[0]);
+  eassert (0 <= fds[1]);
+  if (fcntl (fds[0], F_SETFL, O_NONBLOCK) != 0)
+    emacs_perror ("fcntl");
+  if (fcntl (fds[1], F_SETFL, O_NONBLOCK) != 0)
+    emacs_perror ("fcntl");
+  add_read_fd (fds[0], child_signal_read, NULL);
+  fd_callback_info[fds[0]].flags &= ~KEYBOARD_FD;
+  child_signal_read_fd = fds[0];
+  child_signal_write_fd = fds[1];
+#endif  /* !WINDOWSNT */
+}
+
+#ifndef WINDOWSNT
+/* Consume a process status change.  */
+
+static void
+child_signal_read (int fd, void *data)
+{
+  eassert (0 <= fd);
+  eassert (fd == child_signal_read_fd);
+  char dummy;
+  if (emacs_read (fd, &dummy, 1) < 0)
+    emacs_perror ("reading from child signal FD");
+}
+#endif  /* !WINDOWSNT */
+
+/* Notify `wait_reading_process_output' of a process status
+   change.  */
+
+static void
+child_signal_notify (void)
+{
+#ifndef WINDOWSNT
+  int fd = child_signal_write_fd;
+  eassert (0 <= fd);
+  char dummy = 0;
+  if (emacs_write (fd, &dummy, 1) != 1)
+    emacs_perror ("writing to child signal FD");
+#endif
+}
 
 /* LIB_CHILD_HANDLER is a SIGCHLD handler that Emacs calls while doing
    its own SIGCHLD handling.  On POSIXish systems, glib needs this to
@@ -7152,6 +7273,7 @@ static void
 handle_child_signal (int sig)
 {
   Lisp_Object tail, proc;
+  bool changed = false;
 
   /* Find the process that signaled us, and record its status.  */
 
@@ -7174,6 +7296,7 @@ handle_child_signal (int sig)
           eassert (ok);
           if (child_status_changed (deleted_pid, 0, 0))
             {
+              changed = true;
               if (STRINGP (XCDR (head)))
                 unlink (SSDATA (XCDR (head)));
               XSETCAR (tail, Qnil);
@@ -7191,6 +7314,7 @@ handle_child_signal (int sig)
           && child_status_changed (p->pid, &status, WUNTRACED | WCONTINUED))
         {
           /* Change the status of the process that was found.  */
+          changed = true;
           p->tick = ++process_tick;
           p->raw_status = status;
           p->raw_status_new = 1;
@@ -7210,6 +7334,10 @@ handle_child_signal (int sig)
         }
     }
 
+  if (changed)
+    /* Wake up `wait_reading_process_output'.  */
+    child_signal_notify ();
+
   lib_child_handler (sig);
 #ifdef NS_IMPL_GNUSTEP
   /* NSTask in GNUstep sets its child handler each time it is called.
diff --git a/src/term.c b/src/term.c
index a87f9c745ce..1059b0669a7 100644
--- a/src/term.c
+++ b/src/term.c
@@ -790,7 +790,7 @@ tty_write_glyphs (struct frame *f, struct glyph *string, int len)
   cmcheckmagic (tty);
 }
 
-#ifdef HAVE_GPM                 /* Only used by GPM code.  */
+#ifndef DOS_NT
 
 static void
 tty_write_glyphs_with_face (register struct frame *f, register struct glyph *string,
@@ -847,6 +847,7 @@ tty_write_glyphs_with_face (register struct frame *f, register struct glyph *str
 
   cmcheckmagic (tty);
 }
+
 #endif
 
 /* An implementation of insert_glyphs for termcap frames. */
@@ -2380,25 +2381,9 @@ frame's terminal). */)
                                Mouse
  ***********************************************************************/
 
-#ifdef HAVE_GPM
-
-#ifndef HAVE_WINDOW_SYSTEM
-void
-term_mouse_moveto (int x, int y)
-{
-  /* TODO: how to set mouse position?
-  const char *name;
-  int fd;
-  name = (const char *) ttyname (0);
-  fd = emacs_open (name, O_WRONLY, 0);
-     SOME_FUNCTION (x, y, fd);
-  emacs_close (fd);
-  last_mouse_x = x;
-  last_mouse_y = y;  */
-}
-#endif /* HAVE_WINDOW_SYSTEM */
+#ifndef DOS_NT
 
-/* Implementation of draw_row_with_mouse_face for TTY/GPM.  */
+/* Implementation of draw_row_with_mouse_face for TTY/GPM and macOS.  */
 void
 tty_draw_row_with_mouse_face (struct window *w, struct glyph_row *row,
                               int start_hpos, int end_hpos,
@@ -2430,6 +2415,24 @@ tty_draw_row_with_mouse_face (struct window *w, struct glyph_row *row,
   cursor_to (f, save_y, save_x);
 }
 
+#endif
+
+#ifdef HAVE_GPM
+
+void
+term_mouse_moveto (int x, int y)
+{
+  /* TODO: how to set mouse position?
+  const char *name;
+  int fd;
+  name = (const char *) ttyname (0);
+  fd = emacs_open (name, O_WRONLY, 0);
+     SOME_FUNCTION (x, y, fd);
+  emacs_close (fd);
+  last_mouse_x = x;
+  last_mouse_y = y;  */
+}
+
 /* Return the current time, as a Time value.  Wrap around on overflow.  */
 static Time
 current_Time (void)
@@ -4246,8 +4249,8 @@ use the Bourne shell command 'TERM=...; export TERM' (C-shell:\n\
 
 #ifdef HAVE_GPM
   terminal->mouse_position_hook = term_mouse_position;
-  tty->mouse_highlight.mouse_face_window = Qnil;
 #endif
+  tty->mouse_highlight.mouse_face_window = Qnil;
 
   terminal->kboard = allocate_kboard (Qnil);
   terminal->kboard->reference_count++;
diff --git a/src/termhooks.h b/src/termhooks.h
index 85a47c071b6..3800679e803 100644
--- a/src/termhooks.h
+++ b/src/termhooks.h
@@ -366,9 +366,7 @@ enum {
 #ifdef HAVE_GPM
 #include <gpm.h>
 extern int handle_one_term_event (struct tty_display_info *, Gpm_Event *);
-#ifndef HAVE_WINDOW_SYSTEM
 extern void term_mouse_moveto (int, int);
-#endif
 
 /* The device for which we have enabled gpm support.  */
 extern struct tty_display_info *gpm_tty;
diff --git a/src/window.c b/src/window.c
index e025e0b0821..eb16e2a4338 100644
--- a/src/window.c
+++ b/src/window.c
@@ -2260,7 +2260,7 @@ return value is a list of elements of the form (PARAMETER . VALUE).  */)
 Lisp_Object
 window_parameter (struct window *w, Lisp_Object parameter)
 {
-  Lisp_Object result = Fassq (parameter, w->window_parameters);
+  Lisp_Object result = assq_no_quit (parameter, w->window_parameters);
 
   return CDR_SAFE (result);
 }
diff --git a/src/xdisp.c b/src/xdisp.c
index ea67329cff1..e1e4ff41365 100644
--- a/src/xdisp.c
+++ b/src/xdisp.c
@@ -20822,9 +20822,8 @@ try_window_id (struct window *w)
                      + window_wants_header_line (w)
                      + window_internal_height (w));
 
-#if defined (HAVE_GPM) || defined (MSDOS)
           gui_clear_window_mouse_face (w);
-#endif
+
           /* Perform the operation on the screen.  */
           if (dvpos > 0)
             {
@@ -31928,9 +31927,8 @@ draw_row_with_mouse_face (struct window *w, int start_x, struct glyph_row *row,
       return;
     }
 #endif
-#if defined (HAVE_GPM) || defined (MSDOS) || defined (WINDOWSNT)
+
   tty_draw_row_with_mouse_face (w, row, start_hpos, end_hpos, draw);
-#endif
 }
 
 /* Display the active region described by mouse_face_* according to DRAW.  */
diff --git a/test/Makefile.in b/test/Makefile.in
index 849fbbf474e..bfab95b9381 100644
--- a/test/Makefile.in
+++ b/test/Makefile.in
@@ -253,11 +253,17 @@ endef
 
 $(foreach test,${TESTS},$(eval $(call test_template,${test})))
 
-# Get the tests for only a specific directory
-NET_TESTS := $(patsubst %.el,%,$(wildcard lisp/net/*.el))
-LISP_TESTS := $(patsubst %.el,%,$(wildcard lisp/*.el))
-check-net: ${NET_TESTS}
-check-lisp: ${LISP_TESTS}
+## Get the tests for only a specific directory.
+SUBDIRS = $(sort $(shell find lib-src lisp src -type d ! -path "*resources*" -print))
+
+define subdir_template
+  .PHONY: check-$(subst /,-,$(1))
+  check-$(subst /,-,$(1)):
+        @${MAKE} check LOGFILES="$(patsubst %.el,%.log, \
+                $(patsubst $(srcdir)/%,%,$(wildcard $(1)/*.el)))"
+endef
+
+$(foreach subdir, $(SUBDIRS), $(eval $(call subdir_template,$(subdir))))
 
 ifeq (@HAVE_MODULES@, yes)
 # -fPIC is a no-op on Windows, but causes a compiler warning
@@ -325,10 +331,10 @@ check-doit:
 ifeq ($(TEST_INTERACTIVE), yes)
         HOME=$(TEST_HOME) $(emacs) \
           -l ert ${ert_opts} \
-          $(patsubst %,-l %,$(if $(findstring $(TEST_LOAD_EL),yes),$ELFILES,$(ELFILES:.el=)))  \
+          $(patsubst %,-l %,$(if $(findstring $(TEST_LOAD_EL),yes),$ELFILES,$(ELFILES:.el=))) \
           $(TEST_RUN_ERT)
 else
-        -@${MAKE} -k  ${LOGFILES}
+        -@${MAKE} -k ${LOGFILES}
         @$(emacs) --batch -l ert --eval \
         "(ert-summarize-tests-batch-and-exit ${SUMMARIZE_TESTS})" ${LOGFILES}
 endif
diff --git a/test/README b/test/README
index 38f4a109701..5f3c10adbe1 100644
--- a/test/README
+++ b/test/README
@@ -39,11 +39,10 @@ The Makefile in this directory supports the following targets:
 * make check-all
   Like "make check", but run all tests.
 
-* make check-lisp
-  Like "make check", but run only the tests in test/lisp/*.el
-
-* make check-net
-  Like "make check", but run only the tests in test/lisp/net/*.el
+* make check-<dirname>
+  Like "make check", but run only the tests in test/<dirname>/*.el.
+  <dirname> is a relative directory path, which has replaced "/" by "-",
+  like in "check-src" or "check-lisp-net".
 
 * make <filename>  -or-  make <filename>.log
   Run all tests declared in <filename>.el.  This includes expensive
@@ -61,7 +60,9 @@ https://www.gnu.org/software/emacs/manual/html_node/ert/Test-Selectors.html
 
 You could use predefined selectors of the Makefile.  "make <filename>
 SELECTOR='$(SELECTOR_DEFAULT)'" runs all tests for <filename>.el
-except the tests tagged as expensive or unstable.
+except the tests tagged as expensive or unstable.  Other predefined
+selectors are $(SELECTOR_EXPENSIVE) (run all tests except unstable
+ones) and $(SELECTOR_ALL) (run all tests).
 
 If your test file contains the tests "test-foo", "test2-foo" and
 "test-foo-remote", and you want to run only the former two tests, you
diff --git a/test/file-organization.org b/test/file-organization.org
index efc354529c5..7cf5b88d6d0 100644
--- a/test/file-organization.org
+++ b/test/file-organization.org
@@ -17,13 +17,15 @@ Sub-directories are in many cases themed after packages (~gnus~, ~org~,
 ~calc~), related functionality (~net~, ~emacs-lisp~, ~progmodes~) or status
 (~obsolete~).
 
-C source is stored in the ~src~ directory, which is flat.
+C source is stored in the ~src~ directory, which is flat.  Source for
+utility programs is stored in the ~lib-src~ directory.
 
 ** Test Files
 
 Automated tests should be stored in the ~test/lisp~ directory for
-tests of functionality implemented in Lisp, and in the ~test/src~
-directory for functionality implemented in C.  Tests should reflect
+tests of functionality implemented in Lisp, in the ~test/src~
+directory for functionality implemented in C, and in the
+~test/lib-src~ directory for utility programs.  Tests should reflect
 the directory structure of the source tree; so tests for files in the
 ~lisp/emacs-lisp~ source directory should reside in the
 ~test/lisp/emacs-lisp~ directory.
@@ -36,10 +38,10 @@ files of any name which are themselves placed in a directory named
 after the feature with ~-tests~ appended, such as
 ~/test/lisp/emacs-lisp/eieio-tests~
 
-Similarly, features implemented in C should reside in ~/test/src~ and
-be named after the C file with ~-tests.el~ added to the base-name of
-the tested source file.  Thus, tests for ~src/fileio.c~ should be in
-~test/src/fileio-tests.el~.
+Similarly, tests of features implemented in C should reside in
+~/test/src~ or in ~test/lib-src~ and be named after the C file with
+~-tests.el~ added to the base-name of the tested source file.  Thus,
+tests for ~src/fileio.c~ should be in ~test/src/fileio-tests.el~.
 
 There are also some test materials that cannot be run automatically
 (i.e. via ert).  These should be placed in ~/test/manual~; they are
diff --git a/test/infra/Dockerfile.emba b/test/infra/Dockerfile.emba
index dd41982ad59..421264db9c9 100644
--- a/test/infra/Dockerfile.emba
+++ b/test/infra/Dockerfile.emba
@@ -41,7 +41,7 @@ COPY . /checkout
 WORKDIR /checkout
 RUN ./autogen.sh autoconf
 RUN ./configure --without-makeinfo
-RUN make bootstrap
+RUN make -j4 bootstrap
 RUN make -j4
 
 FROM emacs-base as emacs-filenotify-gio
diff --git a/test/infra/gitlab-ci.yml b/test/infra/gitlab-ci.yml
new file mode 100644
index 00000000000..5a0ab54e4b9
--- /dev/null
+++ b/test/infra/gitlab-ci.yml
@@ -0,0 +1,245 @@
+# Copyright (C) 2017-2021 Free Software Foundation, Inc.
+#
+#  This file is part of GNU Emacs.
+#
+#  GNU Emacs is free software: you can redistribute it and/or modify
+#  it under the terms of the GNU General Public License as published by
+#  the Free Software Foundation, either version 3 of the License, or
+#  (at your option) any later version.
+#
+#  GNU Emacs is distributed in the hope that it will be useful,
+#  but WITHOUT ANY WARRANTY; without even the implied warranty of
+#  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+#  GNU General Public License for more details.
+#
+#  You should have received a copy of the GNU General Public License
+#  along with GNU Emacs.  If not, see <https://www.gnu.org/licenses/>.
+
+# GNU Emacs support for the GitLab protocol for CI
+
+# The presence of this file does not imply any FSF/GNU endorsement of
+# any particular service that uses that protocol.  Also, it is intended for
+# evaluation purposes, thus possibly temporary.
+
+# Maintainer: Ted Zlatanov <tzz@lifelogs.com>
+# URL: https://emba.gnu.org/emacs/emacs
+
+# Never run merge request pipelines, they usually duplicate push pipelines
+# see https://docs.gitlab.com/ee/ci/yaml/README.html#common-if-clauses-for-rules
+
+# Rules: always run tags and branches named master*, emacs*, feature*, fix*
+# Test that it triggers by pushing a tag: `git tag mytag; git push origin mytag`
+# Test that it triggers by pushing to: feature/emba, feature1, master, master-2, fix/emba, emacs-299, fix-2
+# Test that it doesn't trigger by pushing to: scratch-2, scratch/emba, oldbranch, dev
+workflow:
+  rules:
+    - if: '$CI_PIPELINE_SOURCE == "merge_request_event"'
+      when: never
+    - if: '$CI_COMMIT_TAG'
+      when: always
+    - if: '$CI_COMMIT_BRANCH !~ /^(master|emacs|feature|fix)/'
+      when: never
+    - when: always
+
+variables:
+  GIT_STRATEGY: fetch
+  EMACS_EMBA_CI: 1
+  # # Use TLS https://docs.gitlab.com/ee/ci/docker/using_docker_build.html#tls-enabled
+  # DOCKER_HOST: tcp://docker:2376
+  # DOCKER_TLS_CERTDIR: "/certs"
+  # Put the configuration for each run in a separate directory to avoid conflicts
+  DOCKER_CONFIG: "/.docker-config-${CI_COMMIT_SHA}"
+  # We don't use ${CI_COMMIT_SHA} to be able to do one bootstrap across multiple builds
+  BUILD_TAG: ${CI_COMMIT_REF_SLUG}
+
+default:
+  image: docker:19.03.12
+  timeout: 3 hours
+  before_script:
+    - docker info
+    - echo "docker registry is ${CI_REGISTRY}"
+    - docker login -u ${CI_REGISTRY_USER} -p ${CI_REGISTRY_PASSWORD} ${CI_REGISTRY}
+
+.job-template:
+  rules:
+    - changes:
+        - "**/Makefile.in"
+        - .gitlab-ci.yml
+        - aclocal.m4
+        - autogen.sh
+        - configure.ac
+        - lib/*.{h,c}
+        - lisp/**/*.el
+        - src/*.{h,c}
+        - test/infra/*
+        - test/lib-src/*.el
+        - test/lisp/**/*.el
+        - test/src/*.el
+    - changes:
+        # gfilemonitor, kqueue
+        - src/gfilenotify.c
+        - src/kqueue.c
+        # MS Windows
+        - "**/w32*"
+        # GNUstep
+        - lisp/term/ns-win.el
+        - src/ns*.{h,m}
+        - src/macfont.{h,m}
+      when: never
+  # these will be cached across builds
+  cache:
+    key: ${CI_COMMIT_SHA}
+    paths: []
+    policy: pull-push
+  # these will be saved for followup builds
+  artifacts:
+    expire_in: 24 hrs
+    paths: []
+      # - "test/**/*.log"
+      # - "**/*.log"
+  # using the variables for each job
+  script:
+    - docker pull ${CI_REGISTRY_IMAGE}:${target}-${BUILD_TAG}
+    # TODO: with make -j4 several of the tests were failing, for example shadowfile-tests, but passed without it
+    - 'export PWD=$(pwd)'
+    - 'docker run -i --rm -e EMACS_EMBA_CI=${EMACS_EMBA_CI} --volumes-from $(docker ps -q -f "label=com.gitlab.gitlab-runner.job.id=${CI_JOB_ID}"):ro ${CI_REGISTRY_IMAGE}:${target}-${BUILD_TAG} /bin/bash -c "git fetch ${PWD} HEAD && echo checking out these updated files && git diff --name-only FETCH_HEAD && ( git diff --name-only FETCH_HEAD | xargs git checkout -f FETCH_HEAD ) && make -j4 && make ${make_params}"'
+
+.build-template:
+  rules:
+    - if: '$CI_PIPELINE_SOURCE == "web"'
+      when: always
+    - changes:
+        - "**/Makefile.in"
+        - .gitlab-ci.yml
+        - aclocal.m4
+        - autogen.sh
+        - configure.ac
+        - lib/*.{h,c}
+        - lisp/emacs-lisp/*.el
+        - src/*.{h,c}
+        - test/infra/*
+    - changes:
+        # gfilemonitor, kqueue
+        - src/gfilenotify.c
+        - src/kqueue.c
+        # MS Windows
+        - "**/w32*"
+        # GNUstep
+        - lisp/term/ns-win.el
+        - src/ns*.{h,m}
+        - src/macfont.{h,m}
+      when: never
+  script:
+    - docker build --pull --target ${target} -t ${CI_REGISTRY_IMAGE}:${target}-${BUILD_TAG} -f test/infra/Dockerfile.emba .
+    - docker push ${CI_REGISTRY_IMAGE}:${target}-${BUILD_TAG}
+
+.gnustep-template:
+  rules:
+    - if: '$CI_PIPELINE_SOURCE == "web"'
+    - if: '$CI_PIPELINE_SOURCE == "schedule"'
+      changes:
+        - "**/Makefile.in"
+        - .gitlab-ci.yml
+        - configure.ac
+        - src/ns*.{h,m}
+        - src/macfont.{h,m}
+        - lisp/term/ns-win.el
+        - nextstep/**/*
+        - test/infra/*
+
+.filenotify-gio-template:
+  rules:
+    - if: '$CI_PIPELINE_SOURCE == "web"'
+    - if: '$CI_PIPELINE_SOURCE == "schedule"'
+      changes:
+        - "**/Makefile.in"
+        - .gitlab-ci.yml
+        - lisp/autorevert.el
+        - lisp/filenotify.el
+        - lisp/net/tramp-sh.el
+        - src/gfilenotify.c
+        - test/infra/*
+        - test/lisp/autorevert-tests.el
+        - test/lisp/filenotify-tests.el
+
+stages:
+  - prep-images
+  - build-images
+  - fast
+  - normal
+  - platform-images
+  - platforms
+  - slow
+
+prep-image-base:
+  stage: prep-images
+  extends: [.job-template, .build-template]
+  variables:
+    target: emacs-base
+
+build-image-inotify:
+  stage: build-images
+  extends: [.job-template, .build-template]
+  variables:
+    target: emacs-inotify
+
+test-fast-inotify:
+  stage: fast
+  extends: [.job-template]
+  variables:
+    target: emacs-inotify
+    make_params: "-C test check"
+
+build-image-filenotify-gio:
+  stage: platform-images
+  extends: [.job-template, .build-template, .filenotify-gio-template]
+  variables:
+    target: emacs-filenotify-gio
+
+build-image-gnustep:
+  stage: platform-images
+  extends: [.job-template, .build-template, .gnustep-template]
+  variables:
+    target: emacs-gnustep
+
+test-lisp-inotify:
+  stage: normal
+  extends: [.job-template]
+  variables:
+    target: emacs-inotify
+    make_params: "-C test check-lisp"
+
+test-lisp-net-inotify:
+  stage: normal
+  extends: [.job-template]
+  variables:
+    target: emacs-inotify
+    make_params: "-C test check-lisp-net"
+
+test-filenotify-gio:
+  # This tests file monitor libraries gfilemonitor and gio.
+  stage: platforms
+  extends: [.job-template, .filenotify-gio-template]
+  variables:
+    target: emacs-filenotify-gio
+    make_params: "-k -C test autorevert-tests filenotify-tests"
+
+test-gnustep:
+  # This tests the GNUstep build process
+  stage: platforms
+  extends: [.job-template, .gnustep-template]
+  variables:
+    target: emacs-gnustep
+    make_params: install
+
+test-all-inotify:
+  # This tests also file monitor libraries inotify and inotifywatch.
+  stage: slow
+  extends: [.job-template]
+  rules:
+    # note there's no "changes" section, so this always runs on a schedule
+    - if: '$CI_PIPELINE_SOURCE == "web"'
+    - if: '$CI_PIPELINE_SOURCE == "schedule"'
+  variables:
+    target: emacs-inotify
+    make_params: check-expensive
diff --git a/test/lisp/autorevert-tests.el b/test/lisp/autorevert-tests.el
index 6da515bb2c8..45cf6353960 100644
--- a/test/lisp/autorevert-tests.el
+++ b/test/lisp/autorevert-tests.el
@@ -524,8 +524,10 @@ This expects `auto-revert--messages' to be bound by
            (auto-revert-test--write-file "1-b" file-1)
            (auto-revert-test--wait-for-buffer-text
             buf-1 "1-b" (auto-revert--timeout))
-           (should (buffer-local-value
-                    'auto-revert-notify-watch-descriptor buf-1))
+           ;; On emba, `buf-1' is a killed buffer.
+           (when (buffer-live-p buf-1)
+             (should (buffer-local-value
+                      'auto-revert-notify-watch-descriptor buf-1)))
 
            ;; Write a buffer to a new file, then modify the new file on disk.
            (with-current-buffer buf-2
@@ -607,11 +609,12 @@ This expects `auto-revert--messages' to be bound by
              (should auto-revert-mode))
 
            (dotimes (i num-buffers)
-             (add-to-list
-              'buffers
-              (make-indirect-buffer
-               (car buffers) (format "%s-%d" (buffer-file-name (car buffers)) i) 'clone)
-              'append))
+             (push (make-indirect-buffer
+                    (car buffers)
+                    (format "%s-%d" (buffer-file-name (car buffers)) i)
+                    'clone)
+                   buffers))
+           (setq buffers (nreverse buffers))
            (dolist (buf buffers)
              (with-current-buffer buf
                (should (string-equal (buffer-string) "any text"))
@@ -638,10 +641,10 @@ This expects `auto-revert--messages' to be bound by
            (auto-revert-tests--write-file "any text" tmpfile (pop times))
 
            (dotimes (i num-buffers)
-             (add-to-list
-              'buffers
-              (generate-new-buffer (format "%s-%d" (file-name-nondirectory tmpfile) i))
-              'append))
+             (push (generate-new-buffer
+                    (format "%s-%d" (file-name-nondirectory tmpfile) i))
+                   buffers))
+           (setq buffers (nreverse buffers))
            (dolist (buf buffers)
              (with-current-buffer buf
                (insert-file-contents tmpfile 'visit)
diff --git a/test/lisp/emacs-lisp/bytecomp-resources/foo-inlinable.el b/test/lisp/emacs-lisp/bytecomp-resources/foo-inlinable.el
new file mode 100644
index 00000000000..47481574ea8
--- /dev/null
+++ b/test/lisp/emacs-lisp/bytecomp-resources/foo-inlinable.el
@@ -0,0 +1,6 @@
+;; -*- lexical-binding: t; -*-
+
+(defsubst foo-inlineable (foo-var)
+  (+ foo-var 2))
+
+(provide 'foo-inlinable)
diff --git a/test/lisp/emacs-lisp/bytecomp-resources/nowarn-inline-after-defvar.el b/test/lisp/emacs-lisp/bytecomp-resources/nowarn-inline-after-defvar.el
new file mode 100644
index 00000000000..5582b2ab0ea
--- /dev/null
+++ b/test/lisp/emacs-lisp/bytecomp-resources/nowarn-inline-after-defvar.el
@@ -0,0 +1,17 @@
+;; -*- lexical-binding: t; -*-
+
+;; In this test, we try and make sure that inlined functions's code isn't
+;; mistakenly re-interpreted in the caller's context: we import an
+;; inlinable function from another file where `foo-var' is a normal
+;; lexical variable, and then call(inline) it in a function where
+;; `foo-var' is a dynamically-scoped variable.
+
+(require 'foo-inlinable
+         (expand-file-name "foo-inlinable.el"
+                           (file-name-directory
+                            (or byte-compile-current-file load-file-name))))
+
+(defvar foo-var)
+
+(defun foo-fun ()
+  (+ (foo-inlineable 5) 1))
diff --git a/test/lisp/emacs-lisp/bytecomp-tests.el b/test/lisp/emacs-lisp/bytecomp-tests.el
index a07af188fac..980b402ca2d 100644
--- a/test/lisp/emacs-lisp/bytecomp-tests.el
+++ b/test/lisp/emacs-lisp/bytecomp-tests.el
@@ -617,13 +617,13 @@ Subtests signal errors if something goes wrong."
 (make-obsolete-variable 'bytecomp--tests-obsolete-var nil "99.99")
 
 (bytecomp--define-warning-file-test "warn-obsolete-hook.el"
-                            "bytecomp--tests-obs.*obsolete.*99.99")
+                            "bytecomp--tests-obs.*obsolete[^z-a]*99.99")
 
 (bytecomp--define-warning-file-test "warn-obsolete-variable-same-file.el"
                             "foo-obs.*obsolete.*99.99" t)
 
 (bytecomp--define-warning-file-test "warn-obsolete-variable.el"
-                            "bytecomp--tests-obs.*obsolete.*99.99")
+                            "bytecomp--tests-obs.*obsolete[^z-a]*99.99")
 
 (bytecomp--define-warning-file-test "warn-obsolete-variable-bound.el"
                             "bytecomp--tests-obs.*obsolete.*99.99" t)
@@ -713,6 +713,10 @@ Subtests signal errors if something goes wrong."
  "warn-wide-docstring-multiline.el"
  "defvar.*foo.*wider than.*characters")
 
+(bytecomp--define-warning-file-test
+ "nowarn-inline-after-defvar.el"
+ "Lexical argument shadows" 'reverse)
+
 
 ;;;; Macro expansion.
 
diff --git a/test/lisp/emacs-lisp/cl-lib-tests.el b/test/lisp/emacs-lisp/cl-lib-tests.el
index 97a44c43ef7..065ca4fa651 100644
--- a/test/lisp/emacs-lisp/cl-lib-tests.el
+++ b/test/lisp/emacs-lisp/cl-lib-tests.el
@@ -543,15 +543,7 @@
                            (apply (lambda (x) (+ x 1)) (list 8)))))
                  '(5 (6 5) (6 6) 9))))
 
-(defun cl-lib-tests--dummy-function ()
-  ;; Dummy function to see if the file is compiled.
-  t)
-
 (ert-deftest cl-lib-defstruct-record ()
-  ;; This test fails when compiled, see Bug#24402/27718.
-  :expected-result (if (byte-code-function-p
-                        (symbol-function 'cl-lib-tests--dummy-function))
-                       :failed :passed)
   (cl-defstruct foo x)
   (let ((x (make-foo :x 42)))
     (should (recordp x))
@@ -566,6 +558,7 @@
     (should (eq (type-of x) 'vector))
 
     (cl-old-struct-compat-mode 1)
+    (defvar cl-struct-foo)
     (let ((cl-struct-foo (cl--struct-get-class 'foo)))
       (setf (symbol-function 'cl-struct-foo) :quick-object-witness-check)
       (should (eq (type-of x) 'foo))
diff --git a/test/lisp/emacs-lisp/pcase-tests.el b/test/lisp/emacs-lisp/pcase-tests.el
index 1b06c6e7543..e6f4c097504 100644
--- a/test/lisp/emacs-lisp/pcase-tests.el
+++ b/test/lisp/emacs-lisp/pcase-tests.el
@@ -32,6 +32,10 @@
   (should (equal (pcase '(2 . 3)        ;bug#18554
                    (`(,hd . ,(and (pred atom) tl)) (list hd tl))
                    ((pred consp) nil))
+                 '(2 3)))
+  (should (equal (pcase '(2 . 3)
+                   (`(,hd . ,(and (pred (not consp)) tl)) (list hd tl))
+                   ((pred consp) nil))
                  '(2 3))))
 
 (pcase-defmacro pcase-tests-plus (pat n)
diff --git a/test/lisp/emacs-lisp/seq-tests.el b/test/lisp/emacs-lisp/seq-tests.el
index 670398354a6..05c7fbe781e 100644
--- a/test/lisp/emacs-lisp/seq-tests.el
+++ b/test/lisp/emacs-lisp/seq-tests.el
@@ -29,6 +29,9 @@
 (require 'ert)
 (require 'seq)
 
+(eval-when-compile
+  (require 'cl-lib))
+
 (defmacro with-test-sequences (spec &rest body)
   "Successively bind VAR to a list, vector, and string built from SEQ.
 Evaluate BODY for each created sequence.
@@ -108,16 +111,12 @@ Evaluate BODY for each created sequence.
                  '((a 0) (b 1) (c 2) (d 3)))))
 
 (ert-deftest test-seq-do-indexed ()
-  (let ((result nil))
-    (seq-do-indexed (lambda (elt i)
-                      (add-to-list 'result (list elt i)))
-                    nil)
-    (should (equal result nil)))
+  (let (result)
+    (seq-do-indexed (lambda (elt i) (push (list elt i) result)) ())
+    (should-not result))
   (with-test-sequences (seq '(4 5 6))
-    (let ((result nil))
-      (seq-do-indexed (lambda (elt i)
-                        (add-to-list 'result (list elt i)))
-                      seq)
+    (let (result)
+      (seq-do-indexed (lambda (elt i) (push (list elt i) result)) seq)
       (should (equal (seq-elt result 0) '(6 2)))
       (should (equal (seq-elt result 1) '(5 1)))
       (should (equal (seq-elt result 2) '(4 0))))))
@@ -410,12 +409,10 @@ Evaluate BODY for each created sequence.
 
 (ert-deftest test-seq-random-elt-take-all ()
   (let ((seq '(a b c d e))
-        (elts '()))
-    (should (= 0 (length elts)))
+        elts)
     (dotimes (_ 1000)
       (let ((random-elt (seq-random-elt seq)))
-        (add-to-list 'elts
-                     random-elt)))
+        (cl-pushnew random-elt elts)))
     (should (= 5 (length elts)))))
 
 (ert-deftest test-seq-random-elt-signal-on-empty ()
diff --git a/test/lisp/faces-tests.el b/test/lisp/faces-tests.el
index 6e77259fe1b..c0db9c9de17 100644
--- a/test/lisp/faces-tests.el
+++ b/test/lisp/faces-tests.el
@@ -217,5 +217,13 @@
         ))
   )
 
+(ert-deftest test-tty-find-type ()
+  (let ((pred (lambda (string)
+                (locate-library (concat "term/" string ".el")))))
+    (should (tty-find-type pred "cygwin"))
+    (should (tty-find-type pred "cygwin-foo"))
+    (should (equal (tty-find-type pred "xterm") "xterm"))
+    (should (equal (tty-find-type pred "screen.xterm") "screen"))))
+
 (provide 'faces-tests)
 ;;; faces-tests.el ends here
diff --git a/test/lisp/net/tramp-tests.el b/test/lisp/net/tramp-tests.el
index ef0968a3385..7757c55c16b 100644
--- a/test/lisp/net/tramp-tests.el
+++ b/test/lisp/net/tramp-tests.el
@@ -2272,8 +2272,8 @@ This checks also `file-name-as-directory', `file-name-directory',
       (delete-file tmp-name)
       (should-not (file-exists-p tmp-name))
 
-      ;; Trashing files doesn't work for crypted remote files.
-      (unless (tramp--test-crypt-p)
+      ;; Trashing files doesn't work on MS Windows, and for crypted remote files.
+      (unless (or (tramp--test-windows-nt-p) (tramp--test-crypt-p))
         (let ((trash-directory (tramp--test-make-temp-name 'local quoted))
               (delete-by-moving-to-trash t))
           (make-directory trash-directory)
@@ -2786,9 +2786,9 @@ This tests also `file-directory-p' and `file-accessible-directory-p'."
       (should-not (file-directory-p tmp-name1))
 
       ;; Trashing directories works only since Emacs 27.1.  It doesn't
-      ;; work for crypted remote directories and for ange-ftp.
-      (when (and (not (tramp--test-crypt-p)) (not (tramp--test-ftp-p))
-                 (tramp--test-emacs27-p))
+      ;; work on MS Windows, for crypted remote directories and for ange-ftp.
+      (when (and (not  (tramp--test-windows-nt-p)) (not (tramp--test-crypt-p))
+                 (not (tramp--test-ftp-p)) (tramp--test-emacs27-p))
         (let ((trash-directory (tramp--test-make-temp-name 'local quoted))
               (delete-by-moving-to-trash t))
           (make-directory trash-directory)
@@ -5247,7 +5247,7 @@ Use direct async.")
           ;; order to avoid a question.  `explicit-sh-args' echoes the
           ;; test data.
           (with-current-buffer (get-buffer-create "*shell*")
-            (ignore-errors (kill-process (current-buffer)))
+            (ignore-errors (kill-process (get-buffer-process (current-buffer))))
             (should-not explicit-shell-file-name)
             (call-interactively #'shell)
             (with-timeout (10)
@@ -5720,16 +5720,16 @@ This requires restrictions of file name syntax."
    (tramp-find-foreign-file-name-handler tramp-test-temporary-file-directory)
    'tramp-ftp-file-name-handler))
 
+(defun tramp--test-crypt-p ()
+  "Check, whether the remote directory is crypted"
+  (tramp-crypt-file-name-p tramp-test-temporary-file-directory))
+
 (defun tramp--test-docker-p ()
   "Check, whether the docker method is used.
 This does not support some special file names."
   (string-equal
    "docker" (file-remote-p tramp-test-temporary-file-directory 'method)))
 
-(defun tramp--test-crypt-p ()
-  "Check, whether the remote directory is crypted"
-  (tramp-crypt-file-name-p tramp-test-temporary-file-directory))
-
 (defun tramp--test-ftp-p ()
   "Check, whether an FTP-like method is used.
 This does not support globbing characters in file names (yet)."
@@ -5748,7 +5748,7 @@ If optional METHOD is given, it is checked first."
   "Check, whether the remote host runs HP-UX.
 Several special characters do not work properly there."
   ;; We must refill the cache.  `file-truename' does it.
-  (file-truename tramp-test-temporary-file-directory) nil
+  (file-truename tramp-test-temporary-file-directory)
   (string-match-p
    "^HP-UX" (tramp-get-connection-property tramp-test-vec "uname" "")))
 
@@ -5757,7 +5757,7 @@ Several special characters do not work properly there."
 ksh93 makes some strange conversions of non-latin characters into
 a $'' syntax."
   ;; We must refill the cache.  `file-truename' does it.
-  (file-truename tramp-test-temporary-file-directory) nil
+  (file-truename tramp-test-temporary-file-directory)
   (string-match-p
    "ksh$" (tramp-get-connection-property tramp-test-vec "remote-shell" "")))
 
@@ -5787,6 +5787,15 @@ This does not support special file names."
   "Check, whether the remote host runs a based method from tramp-sh.el."
   (tramp-sh-file-name-handler-p tramp-test-vec))
 
+(defun tramp--test-sh-no-ls--dired-p ()
+  "Check, whether the remote host runs a based method from tramp-sh.el.
+Additionally, ls does not support \"--dired\"."
+  (and (tramp--test-sh-p)
+       (with-temp-buffer
+         ;; We must refill the cache.  `insert-directory' does it.
+         (insert-directory tramp-test-temporary-file-directory "-al")
+         (not (tramp-get-connection-property tramp-test-vec "ls--dired" nil)))))
+
 (defun tramp--test-share-p ()
   "Check, whether the method needs a share."
   (and (tramp--test-gvfs-p)
@@ -6023,17 +6032,20 @@ This requires restrictions of file name syntax."
   ;; expanded to <TAB>.
   (let ((files
          (list
-          (if (or (tramp--test-ange-ftp-p)
-                  (tramp--test-gvfs-p)
-                  (tramp--test-rclone-p)
-                  (tramp--test-sudoedit-p)
-                  (tramp--test-windows-nt-or-smb-p))
-              "foo bar baz"
-            (if (or (tramp--test-adb-p)
-                    (tramp--test-docker-p)
-                    (eq system-type 'cygwin))
-                " foo bar baz "
-              " foo\tbar baz\t"))
+          (cond ((or (tramp--test-ange-ftp-p)
+                     (tramp--test-gvfs-p)
+                     (tramp--test-rclone-p)
+                     (tramp--test-sudoedit-p)
+                     (tramp--test-windows-nt-or-smb-p))
+                 "foo bar baz")
+                ((or (tramp--test-adb-p)
+                     (tramp--test-docker-p)
+                     (eq system-type 'cygwin))
+                 " foo bar baz ")
+                ((tramp--test-sh-no-ls--dired-p)
+                 "\tfoo bar baz\t")
+                (t " foo\tbar baz\t"))
+          "@foo@bar@baz@"
           "$foo$bar$$baz$"
           "-foo-bar-baz-"
           "%foo%bar%baz%"
@@ -6349,6 +6361,7 @@ process sentinels.  They shall not disturb each other."
                    (tramp--test-sh-p)))
   (skip-unless (not (tramp--test-crypt-p)))
   (skip-unless (not (tramp--test-docker-p)))
+  (skip-unless (not (tramp--test-windows-nt-p)))
 
   (with-timeout
       (tramp--test-asynchronous-requests-timeout (tramp--test-timeout-handler))
@@ -6358,12 +6371,11 @@ process sentinels.  They shall not disturb each other."
            (shell-file-name (if (tramp--test-adb-p) "/system/bin/sh" "/bin/sh"))
            ;; It doesn't work on w32 systems.
            (watchdog
-            (unless (tramp--test-windows-nt-p)
-              (start-process-shell-command
-               "*watchdog*" nil
-               (format
-                "sleep %d; kill -USR1 %d"
-                tramp--test-asynchronous-requests-timeout (emacs-pid)))))
+            (start-process-shell-command
+             "*watchdog*" nil
+             (format
+              "sleep %d; kill -USR1 %d"
+              tramp--test-asynchronous-requests-timeout (emacs-pid))))
            (tmp-name (tramp--test-make-temp-name))
            (default-directory tmp-name)
            ;; Do not cache Tramp properties.
diff --git a/test/lisp/progmodes/elisp-mode-tests.el b/test/lisp/progmodes/elisp-mode-tests.el
index a10d5dab906..0da0e393535 100644
--- a/test/lisp/progmodes/elisp-mode-tests.el
+++ b/test/lisp/progmodes/elisp-mode-tests.el
@@ -314,7 +314,19 @@
     (let* ((xref (pop xrefs))
            (expected (pop expected-xrefs))
            (expected-xref (or (when (consp expected) (car expected)) expected))
-           (expected-source (when (consp expected) (cdr expected))))
+           (expected-source (when (consp expected) (cdr expected)))
+           (xref-file (xref-elisp-location-file (oref xref location)))
+           (expected-file (xref-elisp-location-file
+                           (oref expected-xref location))))
+
+      ;; Make sure file names compare as strings.
+      (when (file-name-absolute-p xref-file)
+        (setf (xref-elisp-location-file (oref xref location))
+              (file-truename (xref-elisp-location-file (oref xref location)))))
+      (when (file-name-absolute-p expected-file)
+        (setf (xref-elisp-location-file (oref expected-xref location))
+              (file-truename (xref-elisp-location-file
+                              (oref expected-xref location)))))
 
       ;; Downcase the filenames for case-insensitive file systems.
       (when xref--case-insensitive
@@ -822,5 +834,56 @@ to (xref-elisp-test-descr-to-target xref)."
       (indent-region (point-min) (point-max))
       (should (equal (buffer-string) orig)))))
 
+(defun test--font (form search)
+  (with-temp-buffer
+    (emacs-lisp-mode)
+    (if (stringp form)
+        (insert form)
+      (pp form (current-buffer)))
+    (font-lock-debug-fontify)
+    (goto-char (point-min))
+    (and (re-search-forward search nil t)
+         (get-text-property (match-beginning 1) 'face))))
+
+(ert-deftest test-elisp-font-keywords-1 ()
+  ;; Special form.
+  (should (eq (test--font '(if foo bar) "(\\(if\\)")
+              'font-lock-keyword-face))
+  ;; Macro.
+  (should (eq (test--font '(when foo bar) "(\\(when\\)")
+              'font-lock-keyword-face))
+  (should (eq (test--font '(condition-case nil
+                               (foo)
+                             (error (if a b)))
+                          "(\\(if\\)")
+              'font-lock-keyword-face))
+  (should (eq (test--font '(condition-case nil
+                               (foo)
+                             (when (if a b)))
+                          "(\\(when\\)")
+              'nil)))
+
+(ert-deftest test-elisp-font-keywords-2 ()
+  :expected-result :failed ; FIXME bug#43265
+  (should (eq (test--font '(condition-case nil
+                               (foo)
+                             (error (when a b)))
+                          "(\\(when\\)")
+              'font-lock-keyword-face)))
+
+(ert-deftest test-elisp-font-keywords-3 ()
+  :expected-result :failed ; FIXME bug#43265
+  (should (eq (test--font '(setq a '(if when zot))
+                          "(\\(if\\)")
+              nil)))
+
+(ert-deftest test-elisp-font-keywords-if ()
+  :expected-result :failed ; FIXME bug#43265
+  (should (eq (test--font '(condition-case nil
+                               (foo)
+                             ((if foo) (when a b)))
+                          "(\\(if\\)")
+              nil)))
+
 (provide 'elisp-mode-tests)
 ;;; elisp-mode-tests.el ends here
diff --git a/test/lisp/replace-tests.el b/test/lisp/replace-tests.el
index 8c2682a1f13..2db570c97dd 100644
--- a/test/lisp/replace-tests.el
+++ b/test/lisp/replace-tests.el
@@ -587,5 +587,18 @@ bound to HIGHLIGHT-LOCUS."
                               (get-text-property (point) 'occur-target))
           (should (funcall check-overlays has-overlay)))))))
 
+(ert-deftest replace-regexp-bug45973 ()
+  "Test for https://debbugs.gnu.org/45973 ."
+  (let ((before "1RB 1LC 1RC 1RB 1RD 0LE 1LA 1LD 1RH 0LA")
+        (after  "1LB 1RC 1LC 1LB 1LD 0RE 1RA 1RD 1LH 0RA"))
+    (with-temp-buffer
+      (insert before)
+      (goto-char (point-min))
+      (replace-regexp
+       "\\(\\(L\\)\\|\\(R\\)\\)"
+       '(replace-eval-replacement
+         replace-quote
+         (if (match-string 2) "R" "L")))
+      (should (equal (buffer-string) after)))))
 
 ;;; replace-tests.el ends here
diff --git a/test/lisp/thingatpt-tests.el b/test/lisp/thingatpt-tests.el
index c43c81af9fd..62a27f09cbd 100644
--- a/test/lisp/thingatpt-tests.el
+++ b/test/lisp/thingatpt-tests.el
@@ -146,4 +146,48 @@ position to retrieve THING.")
       (should (thing-at-point-looking-at "2abcd"))
       (should (equal (match-data) m2)))))
 
+(ert-deftest test-symbol-thing-1 ()
+  (with-temp-buffer
+    (insert "foo bar zot")
+    (goto-char 4)
+    (should (eq (symbol-at-point) 'foo))
+    (forward-char 1)
+    (should (eq (symbol-at-point) 'bar))
+    (forward-char 1)
+    (should (eq (symbol-at-point) 'bar))
+    (forward-char 1)
+    (should (eq (symbol-at-point) 'bar))
+    (forward-char 1)
+    (should (eq (symbol-at-point) 'bar))
+    (forward-char 1)
+    (should (eq (symbol-at-point) 'zot))))
+
+(ert-deftest test-symbol-thing-2 ()
+  (with-temp-buffer
+    (insert " bar ")
+    (goto-char (point-max))
+    (should (eq (symbol-at-point) nil))
+    (forward-char -1)
+    (should (eq (symbol-at-point) 'bar))))
+
+(ert-deftest test-symbol-thing-2 ()
+  (with-temp-buffer
+    (insert " bar ")
+    (goto-char (point-max))
+    (should (eq (symbol-at-point) nil))
+    (forward-char -1)
+    (should (eq (symbol-at-point) 'bar))))
+
+(ert-deftest test-symbol-thing-3 ()
+  (with-temp-buffer
+    (insert "bar")
+    (goto-char 2)
+    (should (eq (symbol-at-point) 'bar))))
+
+(ert-deftest test-symbol-thing-3 ()
+  (with-temp-buffer
+    (insert "`[[`(")
+    (goto-char 2)
+    (should (eq (symbol-at-point) nil))))
+
 ;;; thingatpt.el ends here
diff --git a/test/lisp/time-stamp-tests.el b/test/lisp/time-stamp-tests.el
index 81488c3df19..4ae3c1917dd 100644
--- a/test/lisp/time-stamp-tests.el
+++ b/test/lisp/time-stamp-tests.el
@@ -262,40 +262,48 @@
 (ert-deftest time-stamp-format-day-of-week ()
   "Test time-stamp formats for named day of week."
   (with-time-stamp-test-env
-    ;; implemented and documented since 1997
-    (should (equal (time-stamp-string "%3a" ref-time1) "Mon"))
-    (should (equal (time-stamp-string "%#A" ref-time1) "MONDAY"))
-    ;; documented 1997-2019
-    (should (equal (time-stamp-string "%3A" ref-time1) "MON"))
-    (should (equal (time-stamp-string "%:a" ref-time1) "Monday"))
-    ;; implemented since 2001, documented since 2019
-    (should (equal (time-stamp-string "%#a" ref-time1) "MON"))
-    (should (equal (time-stamp-string "%:A" ref-time1) "Monday"))
-    ;; allowed but undocumented since 2019 (warned 1997-2019)
-    (should (equal (time-stamp-string "%^A" ref-time1) "MONDAY"))
-    ;; warned 1997-2019, changed in 2019
-    (should (equal (time-stamp-string "%a" ref-time1) "Mon"))
-    (should (equal (time-stamp-string "%^a" ref-time1) "MON"))
-    (should (equal (time-stamp-string "%A" ref-time1) "Monday"))))
+   (let ((Mon (format-time-string "%a" ref-time1 t))
+         (MON (format-time-string "%^a" ref-time1 t))
+         (Monday (format-time-string "%A" ref-time1 t))
+         (MONDAY (format-time-string "%^A" ref-time1 t)))
+     ;; implemented and documented since 1997
+     (should (equal (time-stamp-string "%3a" ref-time1) Mon))
+     (should (equal (time-stamp-string "%#A" ref-time1) MONDAY))
+     ;; documented 1997-2019
+     (should (equal (time-stamp-string "%3A" ref-time1) MON))
+     (should (equal (time-stamp-string "%:a" ref-time1) Monday))
+     ;; implemented since 2001, documented since 2019
+     (should (equal (time-stamp-string "%#a" ref-time1) MON))
+     (should (equal (time-stamp-string "%:A" ref-time1) Monday))
+     ;; allowed but undocumented since 2019 (warned 1997-2019)
+     (should (equal (time-stamp-string "%^A" ref-time1) MONDAY))
+     ;; warned 1997-2019, changed in 2019
+     (should (equal (time-stamp-string "%a" ref-time1) Mon))
+     (should (equal (time-stamp-string "%^a" ref-time1) MON))
+     (should (equal (time-stamp-string "%A" ref-time1) Monday)))))
 
 (ert-deftest time-stamp-format-month-name ()
   "Test time-stamp formats for month name."
   (with-time-stamp-test-env
-    ;; implemented and documented since 1997
-    (should (equal (time-stamp-string "%3b" ref-time1) "Jan"))
-    (should (equal (time-stamp-string "%#B" ref-time1) "JANUARY"))
-    ;; documented 1997-2019
-    (should (equal (time-stamp-string "%3B" ref-time1) "JAN"))
-    (should (equal (time-stamp-string "%:b" ref-time1) "January"))
-    ;; implemented since 2001, documented since 2019
-    (should (equal (time-stamp-string "%#b" ref-time1) "JAN"))
-    (should (equal (time-stamp-string "%:B" ref-time1) "January"))
-    ;; allowed but undocumented since 2019 (warned 1997-2019)
-    (should (equal (time-stamp-string "%^B" ref-time1) "JANUARY"))
-    ;; warned 1997-2019, changed in 2019
-    (should (equal (time-stamp-string "%b" ref-time1) "Jan"))
-    (should (equal (time-stamp-string "%^b" ref-time1) "JAN"))
-    (should (equal (time-stamp-string "%B" ref-time1) "January"))))
+   (let ((Jan (format-time-string "%b" ref-time1 t))
+         (JAN (format-time-string "%^b" ref-time1 t))
+         (January (format-time-string "%B" ref-time1 t))
+         (JANUARY (format-time-string "%^B" ref-time1 t)))
+     ;; implemented and documented since 1997
+     (should (equal (time-stamp-string "%3b" ref-time1) Jan))
+     (should (equal (time-stamp-string "%#B" ref-time1) JANUARY))
+     ;; documented 1997-2019
+     (should (equal (time-stamp-string "%3B" ref-time1) JAN))
+     (should (equal (time-stamp-string "%:b" ref-time1) January))
+     ;; implemented since 2001, documented since 2019
+     (should (equal (time-stamp-string "%#b" ref-time1) JAN))
+     (should (equal (time-stamp-string "%:B" ref-time1) January))
+     ;; allowed but undocumented since 2019 (warned 1997-2019)
+     (should (equal (time-stamp-string "%^B" ref-time1) JANUARY))
+     ;; warned 1997-2019, changed in 2019
+     (should (equal (time-stamp-string "%b" ref-time1) Jan))
+     (should (equal (time-stamp-string "%^b" ref-time1) JAN))
+     (should (equal (time-stamp-string "%B" ref-time1) January)))))
 
 (ert-deftest time-stamp-format-day-of-month ()
   "Test time-stamp formats for day of month."
@@ -483,14 +491,18 @@
 (ert-deftest time-stamp-format-am-pm ()
   "Test time-stamp formats for AM and PM strings."
   (with-time-stamp-test-env
-    ;; implemented and documented since 1997
-    (should (equal (time-stamp-string "%#p" ref-time1) "pm"))
-    (should (equal (time-stamp-string "%#p" ref-time3) "am"))
-    (should (equal (time-stamp-string "%P" ref-time1) "PM"))
-    (should (equal (time-stamp-string "%P" ref-time3) "AM"))
-    ;; warned 1997-2019, changed in 2019
-    (should (equal (time-stamp-string "%p" ref-time1) "PM"))
-    (should (equal (time-stamp-string "%p" ref-time3) "AM"))))
+    (let ((pm (format-time-string "%#p" ref-time1 t))
+          (am (format-time-string "%#p" ref-time3 t))
+          (PM (format-time-string "%p" ref-time1 t))
+          (AM (format-time-string "%p" ref-time3 t)))
+      ;; implemented and documented since 1997
+      (should (equal (time-stamp-string "%#p" ref-time1) pm))
+      (should (equal (time-stamp-string "%#p" ref-time3) am))
+      (should (equal (time-stamp-string "%P" ref-time1) PM))
+      (should (equal (time-stamp-string "%P" ref-time3) AM))
+      ;; warned 1997-2019, changed in 2019
+      (should (equal (time-stamp-string "%p" ref-time1) PM))
+      (should (equal (time-stamp-string "%p" ref-time3) AM)))))
 
 (ert-deftest time-stamp-format-day-number-in-week ()
   "Test time-stamp formats for day number in week."
@@ -567,10 +579,15 @@
 (ert-deftest time-stamp-format-ignored-modifiers ()
   "Test additional args allowed (but ignored) to allow for future expansion."
   (with-time-stamp-test-env
-    ;; allowed modifiers
-    (should (equal (time-stamp-string "%.,@-+_ ^(stuff)P" ref-time3) "AM"))
-    ;; not all punctuation is allowed
-    (should-not (equal (time-stamp-string "%&P" ref-time3) "AM"))))
+   (let ((May (format-time-string "%B" ref-time3 t)))
+     ;; allowed modifiers
+     (should (equal (time-stamp-string "%.,@+ (stuff)B" ref-time3) May))
+     ;; parens nest
+     (should (equal (time-stamp-string "%(st(u)ff)B" ref-time3) May))
+     ;; escaped parens do not change the nesting level
+     (should (equal (time-stamp-string "%(st\\)u\\(ff)B" ref-time3) May))
+     ;; not all punctuation is allowed
+     (should-not (equal (time-stamp-string "%&B" ref-time3) May)))))
 
 (ert-deftest time-stamp-format-non-conversions ()
   "Test that without a %, the text is copied literally."
@@ -580,16 +597,22 @@
 (ert-deftest time-stamp-format-string-width ()
   "Test time-stamp string width modifiers."
   (with-time-stamp-test-env
-    ;; strings truncate on the right or are blank-padded on the left
-    (should (equal (time-stamp-string "%0P" ref-time3) ""))
-    (should (equal (time-stamp-string "%1P" ref-time3) "A"))
-    (should (equal (time-stamp-string "%2P" ref-time3) "AM"))
-    (should (equal (time-stamp-string "%3P" ref-time3) " AM"))
-    (should (equal (time-stamp-string "%0%" ref-time3) ""))
-    (should (equal (time-stamp-string "%1%" ref-time3) "%"))
-    (should (equal (time-stamp-string "%2%" ref-time3) " %"))
-    (should (equal (time-stamp-string "%#3a" ref-time3) "SUN"))
-    (should (equal (time-stamp-string "%#3b" ref-time2) "NOV"))))
+   (let ((May (format-time-string "%b" ref-time3 t))
+         (SUN (format-time-string "%^a" ref-time3 t))
+         (NOV (format-time-string "%^b" ref-time2 t)))
+     ;; strings truncate on the right or are blank-padded on the left
+     (should (equal (time-stamp-string "%0b" ref-time3) ""))
+     (should (equal (time-stamp-string "%1b" ref-time3) (substring May 0 1)))
+     (should (equal (time-stamp-string "%2b" ref-time3) (substring May 0 2)))
+     (should (equal (time-stamp-string "%3b" ref-time3) May))
+     (should (equal (time-stamp-string "%4b" ref-time3) (concat " " May)))
+     (should (equal (time-stamp-string "%0%" ref-time3) ""))
+     (should (equal (time-stamp-string "%1%" ref-time3) "%"))
+     (should (equal (time-stamp-string "%2%" ref-time3) " %"))
+     (should (equal (time-stamp-string "%9%" ref-time3) "        %"))
+     (should (equal (time-stamp-string "%10%" ref-time3) "         %"))
+     (should (equal (time-stamp-string "%#3a" ref-time3) SUN))
+     (should (equal (time-stamp-string "%#3b" ref-time2) NOV)))))
 
 ;;; Tests of helper functions
 
diff --git a/test/lisp/wid-edit-tests.el b/test/lisp/wid-edit-tests.el
index 17fdfefce84..f843649784a 100644
--- a/test/lisp/wid-edit-tests.el
+++ b/test/lisp/wid-edit-tests.el
@@ -322,4 +322,15 @@ return nil, even with a non-nil bubblep argument."
     (widget-backward 1)
     (should (string= "Second" (widget-value (widget-at))))))
 
+(ert-deftest widget-test-color-match ()
+  "Test that the :match function for the color widget works."
+  (let ((widget (widget-convert 'color)))
+    (should (widget-apply widget :match "red"))
+    (should (widget-apply widget :match "#fa3"))
+    (should (widget-apply widget :match "#ff0000"))
+    (should (widget-apply widget :match "#111222333"))
+    (should (widget-apply widget :match "#111122223333"))
+    (should-not (widget-apply widget :match "someundefinedcolorihope"))
+    (should-not (widget-apply widget :match "#11223"))))
+
 ;;; wid-edit-tests.el ends here
diff --git a/test/src/process-tests.el b/test/src/process-tests.el
index 57097cfa052..a3fba8d328b 100644
--- a/test/src/process-tests.el
+++ b/test/src/process-tests.el
@@ -576,11 +576,6 @@ FD_SETSIZE file descriptors (Bug#24325)."
                 (should (memq (process-status process) '(run exit)))
                 (when (process-live-p process)
                   (process-send-eof process))
-                ;; FIXME: This `sleep-for' shouldn't be needed.  It
-                ;; indicates a bug in Emacs; perhaps SIGCHLD is
-                ;; received in parallel with `accept-process-output',
-                ;; causing the latter to hang.
-                (sleep-for 0.1)
                 (while (accept-process-output process))
                 (should (eq (process-status process) 'exit))
                 ;; If there's an error between fork and exec, Emacs
@@ -739,5 +734,150 @@ Return nil if that can't be determined."
                 (match-string-no-properties 1))))))
   process-tests--EMFILE-message)
 
+(ert-deftest process-tests/sentinel-called ()
+  "Check that sentinels are called after processes finish"
+  (let ((command (process-tests--emacs-command)))
+    (skip-unless command)
+    (dolist (conn-type '(pipe pty))
+      (ert-info ((format "Connection type: %s" conn-type))
+        (process-tests--with-processes processes
+          (let* ((calls ())
+                 (process (make-process
+                           :name "echo"
+                           :command (process-tests--eval
+                                     command '(print "first"))
+                           :noquery t
+                           :connection-type conn-type
+                           :coding 'utf-8-unix
+                           :sentinel (lambda (process message)
+                                       (push (list process message)
+                                             calls)))))
+            (push process processes)
+            (while (accept-process-output process))
+            (should (equal calls
+                           (list (list process "finished\n"))))))))))
+
+(ert-deftest process-tests/sentinel-with-multiple-processes ()
+  "Check that sentinels are called in time even when other processes
+have written output."
+  (let ((command (process-tests--emacs-command)))
+    (skip-unless command)
+    (dolist (conn-type '(pipe pty))
+      (ert-info ((format "Connection type: %s" conn-type))
+        (process-tests--with-processes processes
+          (let* ((calls ())
+                 (process (make-process
+                           :name "echo"
+                           :command (process-tests--eval
+                                     command '(print "first"))
+                           :noquery t
+                           :connection-type conn-type
+                           :coding 'utf-8-unix
+                           :sentinel (lambda (process message)
+                                       (push (list process message)
+                                             calls)))))
+            (push process processes)
+            (push (make-process
+                   :name "bash"
+                   :command (process-tests--eval
+                             command
+                             '(progn (sleep-for 10) (print "second")))
+                   :noquery t
+                   :connection-type conn-type)
+                  processes)
+            (while (accept-process-output process))
+            (should (equal calls
+                           (list (list process "finished\n"))))))))))
+
+(ert-deftest process-tests/multiple-threads-waiting ()
+  (skip-unless (fboundp 'make-thread))
+  (with-timeout (60 (ert-fail "Test timed out"))
+    (process-tests--with-processes processes
+      (let ((threads ())
+            (cat (executable-find "cat")))
+        (skip-unless cat)
+        (dotimes (i 10)
+          (let* ((name (format "test %d" i))
+                 (process (make-process :name name
+                                        :command (list cat)
+                                        :coding 'no-conversion
+                                        :noquery t
+                                        :connection-type 'pipe)))
+            (push process processes)
+            (set-process-thread process nil)
+            (push (make-thread
+                   (lambda ()
+                     (while (accept-process-output process)))
+                   name)
+                  threads)))
+        (mapc #'process-send-eof processes)
+        (cl-loop for process in processes
+                 and thread in threads
+                 do
+                 (should-not (thread-join thread))
+                 (should-not (thread-last-error))
+                 (should (eq (process-status process) 'exit))
+                 (should (eql (process-exit-status process) 0)))))))
+
+(defun process-tests--eval (command form)
+  "Return a command that evaluates FORM in an Emacs subprocess.
+COMMAND must be a list returned by
+`process-tests--emacs-command'."
+  (let ((print-gensym t)
+        (print-circle t)
+        (print-length nil)
+        (print-level nil)
+        (print-escape-control-characters t)
+        (print-escape-newlines t)
+        (print-escape-multibyte t)
+        (print-escape-nonascii t))
+    `(,@command "--quick" "--batch" ,(format "--eval=%S" form))))
+
+(defun process-tests--emacs-command ()
+  "Return a command to reinvoke the current Emacs instance.
+Return nil if that doesn't appear to be possible."
+  (when-let ((binary (process-tests--emacs-binary))
+             (dump (process-tests--dump-file)))
+    (cons binary
+          (unless (eq dump :not-needed)
+            (list (concat "--dump-file="
+                          (file-name-unquote dump)))))))
+
+(defun process-tests--emacs-binary ()
+  "Return the filename of the currently running Emacs binary.
+Return nil if that can't be determined."
+  (and (stringp invocation-name)
+       (not (file-remote-p invocation-name))
+       (not (file-name-absolute-p invocation-name))
+       (stringp invocation-directory)
+       (not (file-remote-p invocation-directory))
+       (file-name-absolute-p invocation-directory)
+       (when-let ((file (process-tests--usable-file-for-reinvoke
+                         (expand-file-name invocation-name
+                                           invocation-directory))))
+         (and (file-executable-p file) file))))
+
+(defun process-tests--dump-file ()
+  "Return the filename of the dump file used to start Emacs.
+Return nil if that can't be determined.  Return `:not-needed' if
+Emacs wasn't started with a dump file."
+  (if-let ((stats (and (fboundp 'pdumper-stats) (pdumper-stats))))
+      (when-let ((file (process-tests--usable-file-for-reinvoke
+                        (cdr (assq 'dump-file-name stats)))))
+        (and (file-readable-p file) file))
+    :not-needed))
+
+(defun process-tests--usable-file-for-reinvoke (filename)
+  "Return a version of FILENAME that can be used to reinvoke Emacs.
+Return nil if FILENAME doesn't exist."
+  (when (and (stringp filename)
+             (not (file-remote-p filename)))
+    (cl-callf file-truename filename)
+    (and (stringp filename)
+         (not (file-remote-p filename))
+         (file-name-absolute-p filename)
+         (file-regular-p filename)
+         filename)))
+
 (provide 'process-tests)
 ;;; process-tests.el ends here
diff --git a/test/src/xdisp-tests.el b/test/src/xdisp-tests.el
index ec96d777ffb..4e7d2ad8ab2 100644
--- a/test/src/xdisp-tests.el
+++ b/test/src/xdisp-tests.el
@@ -75,31 +75,28 @@
 (ert-deftest xdisp-tests--window-text-pixel-size () ;; bug#45748
   (with-temp-buffer
     (insert "xxx")
-    (let* ((window
-            (display-buffer (current-buffer) '(display-buffer-in-child-frame . nil)))
-          (char-width (frame-char-width))
-          (size (window-text-pixel-size nil t t)))
-      (delete-frame (window-frame window))
-      (should (equal (/ (car size) char-width) 3)))))
+    (switch-to-buffer (current-buffer))
+    (let* ((char-width (frame-char-width))
+           (size (window-text-pixel-size nil t t))
+           (width-in-chars (/ (car size) char-width)))
+      (should (equal width-in-chars 3)))))
 
 (ert-deftest xdisp-tests--window-text-pixel-size-leading-space () ;; bug#45748
   (with-temp-buffer
     (insert " xx")
-    (let* ((window
-            (display-buffer (current-buffer) '(display-buffer-in-child-frame . nil)))
-          (char-width (frame-char-width))
-          (size (window-text-pixel-size nil t t)))
-      (delete-frame (window-frame window))
-      (should (equal (/ (car size) char-width) 3)))))
+    (switch-to-buffer (current-buffer))
+    (let* ((char-width (frame-char-width))
+           (size (window-text-pixel-size nil t t))
+           (width-in-chars (/ (car size) char-width)))
+      (should (equal width-in-chars 3)))))
 
 (ert-deftest xdisp-tests--window-text-pixel-size-trailing-space () ;; bug#45748
   (with-temp-buffer
     (insert "xx ")
-    (let* ((window
-            (display-buffer (current-buffer) '(display-buffer-in-child-frame . nil)))
-          (char-width (frame-char-width))
-          (size (window-text-pixel-size nil t t)))
-      (delete-frame (window-frame window))
-      (should (equal (/ (car size) char-width) 3)))))
+    (switch-to-buffer (current-buffer))
+    (let* ((char-width (frame-char-width))
+           (size (window-text-pixel-size nil t t))
+           (width-in-chars (/ (car size) char-width)))
+      (should (equal width-in-chars 3)))))
 
 ;;; xdisp-tests.el ends here