Remove highlighting trailing whitespace from cperl-mode

* lisp/progmodes/cperl-mode.el (cperl-invalid-face): Make
obsolete in favor of 'show-trailing-whitespace'.
(cperl-init-faces): No longer highlight trailing whitespace
separately.
(cperl-praise, cperl-tips-faces): Update documentation for above
change.

2 files changed, 6 insertions, 5 deletions

diff --git a/etc/NEWS b/etc/NEWS
index 3ad886bdc2b..05fd1b7a390 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -876,6 +876,10 @@ The Perl documentation in info format is no longer distributed with
 Perl or on CPAN since more than 10 years.  Perl documentation can be
 read with 'cperl-perldoc' instead.
 
+*** Highlighting trailing whitespace has been removed.
+The user option 'cperl-invalid-face' is now obsolete, and does
+nothing.  See the user option 'show-trailing-whitespace' instead.
+
 ** Emacs Sessions (Desktop)
 
 +++
diff --git a/lisp/progmodes/cperl-mode.el b/lisp/progmodes/cperl-mode.el
index 2894f36477a..85495732075 100644
--- a/lisp/progmodes/cperl-mode.el
+++ b/lisp/progmodes/cperl-mode.el
@@ -379,6 +379,8 @@ Font for POD headers."
   :type 'face
   :version "21.1"
   :group 'cperl-faces)
+(make-obsolete-variable 'cperl-invalid-face
+                        'show-trailing-whitespace "30.1")
 
 (defcustom cperl-pod-here-fontify t
   "Not-nil after evaluation means to highlight POD and here-docs sections."
@@ -730,7 +732,6 @@ voice);
 
         m) Highlights (by user-choice) either 3-delimiters constructs
            (such as tr/a/b/), or regular expressions and `y/tr';
-        n) Highlights trailing whitespace;
         o) Is able to manipulate Perl Regular Expressions to ease
            conversion to a more readable form.
         p) Can ispell POD sections and HERE-DOCs.
@@ -828,7 +829,6 @@ B) Speed of editing operations.
   `font-lock-type-face'         Overridable keywords
   `font-lock-variable-name-face' Variable declarations, indirect array and
                                 hash names, POD headers/item names
-  `cperl-invalid-face'          Trailing whitespace
 
 Note that in several situations the highlighting tries to inform about
 possible confusion, such as different colors for function names in
@@ -5858,9 +5858,6 @@ functions (which they are not).  Inherits from `default'.")
           (setq
            t-font-lock-keywords
            (list
-            ;; -------- trailing spaces -> use invalid-face as a warning
-            ;; (matcher subexp facespec)
-            `("[ \t]+$" 0 ',cperl-invalid-face t)
             ;; -------- function definition _and_ declaration
             ;; (matcher (subexp facespec))
             ;; facespec is evaluated depending on whether the