Merge from origin/emacs-26

eb903d8 * lisp/emacs-lisp/pcase.el: Improve docstrings.
86abbb3 * lisp/emacs-lisp/rx.el (rx): Fix typo in doc string.  (Bug#3...
ced58d3 Improve doc string of 'call-process'
38f88a7 Document that generic functions cannot be commands
5aeddfa * lisp/mail/rmailsum.el (rmail-summary-output): Add lost word...
10e0fd8 Add index entries for more isearch commands/bindings (Bug#32990)
de28184 * lisp/simple.el (filter-buffer-substring): Clarify doc (Bug#...
d192c16 Fix recent change in lispref/processes.texi.

3 files changed, 17 insertions, 7 deletions

diff --git a/doc/lispref/commands.texi b/doc/lispref/commands.texi
index 49c839a8971..427379bc79c 100644
--- a/doc/lispref/commands.texi
+++ b/doc/lispref/commands.texi
@@ -136,6 +136,9 @@ start with a capital, e.g., @code{"use (system-name) instead."}); @code{t}; any
 other symbol, which should be an alternative function to use in Lisp
 code.
 
+Generic functions (@pxref{Generic Functions}) cannot be turned into
+commands by adding the @code{interactive} form to them.
+
 @menu
 * Using Interactive::     General rules for @code{interactive}.
 * Interactive Codes::     The standard letter-codes for reading arguments
diff --git a/doc/lispref/functions.texi b/doc/lispref/functions.texi
index 3be52d8e624..69e9919f708 100644
--- a/doc/lispref/functions.texi
+++ b/doc/lispref/functions.texi
@@ -1350,6 +1350,13 @@ to invoke the other auxiliary or primary methods.
 This allows you to add more methods, distinguished by @var{string},
 for the same specializers and qualifiers.
 @end table
+
+Functions defined using @code{cl-defmethod} cannot be made
+interactive, i.e.@: commands (@pxref{Defining Commands}), by adding
+the @code{interactive} form to them.  If you need a polymorphic
+command, we recommend defining a normal command that calls a
+polymorphic function defined via @code{cl-defgeneric} and
+@code{cl-defmethod}.
 @end defmac
 
 @cindex dispatch of methods for generic function
diff --git a/doc/lispref/processes.texi b/doc/lispref/processes.texi
index 2afc6a33828..d88c7fbe622 100644
--- a/doc/lispref/processes.texi
+++ b/doc/lispref/processes.texi
@@ -609,13 +609,13 @@ Shell mode, because they allow for job control (@kbd{C-c}, @kbd{C-z},
 etc.)@: between the process and its children, and because interactive
 programs treat ptys as terminal devices, whereas pipes don't support
 these features.  However, for subprocesses used by Lisp programs for
-internal purposes (i.e., with no user interaction), where significant
-amounts of data need to be exchanged between the subprocess and the
-Lisp program, it is often better to use a pipe, because pipes are
-more efficient, and because they are immune to stray character
-injections that ptys introduce for large (around 500 byte) messages.
-Also, the total number of ptys is limited on many systems, and it is
-good not to waste them unnecessarily.
+internal purposes (i.e., no user interaction with the subprocess is
+required), where significant amounts of data need to be exchanged
+between the subprocess and the Lisp program, it is often better to use
+a pipe, because pipes are more efficient, and because they are immune
+to stray character injections that ptys introduce for large (around
+500 byte) messages.  Also, the total number of ptys is limited on many
+systems, and it is good not to waste them unnecessarily.
 
 @defun make-process &rest args
 This function is the basic low-level primitive for starting