bug#24356: 25.1; query-replace with replace-char-fold doesn't highlight folded chars

bug#24356: 25.1; query-replace with replace-char-fold doesn't highlight folded chars

[Alex]

Recipe:

emacs -Q
M-: (setq replace-char-fold t)
C-x 8 ~ a RET
M-<
M-% a RET bbbb RET

The result of 'C-x 8 ~ a' (ã) is not highlighted as a match; it should
be, as entering '!' will indeed replace ã with bbbb.

It should be noted that isearch in char-fold mode does highlight ã.


In GNU Emacs 25.1.1 (x86_64-unknown-linux-gnu, GTK+ Version 3.20.7)
 of 2016-08-21 built on lylat
Windowing system distributor 'The X.Org Foundation', version 11.0.11804000
System Description:	Debian GNU/Linux testing (stretch)

Configured features:
XPM JPEG TIFF GIF PNG RSVG IMAGEMAGICK SOUND GPM DBUS GCONF GSETTINGS
NOTIFY ACL LIBSELINUX GNUTLS LIBXML2 FREETYPE M17N_FLT LIBOTF XFT ZLIB
TOOLKIT_SCROLL_BARS GTK3 X11

Important settings:
  value of $LC_CTYPE: en_CA.utf8
  value of $LANG: en_CA.utf8
  locale-coding-system: utf-8-unix

Major mode: Lisp Interaction

Minor modes in effect:
  tooltip-mode: t
  global-eldoc-mode: t
  electric-indent-mode: t
  mouse-wheel-mode: t
  tool-bar-mode: t
  menu-bar-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  blink-cursor-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t
  line-number-mode: t
  transient-mark-mode: t

Load-path shadows:
None found.

bug#24356: 25.1; query-replace with replace-char-fold doesn't highlight folded chars

[Charles A. Roelli]

Version: 27.1

> From: Alex <agrambot@gmail.com>
> Date: Fri, 02 Sep 2016 21:51:20 -0600
> 
> Recipe:
> 
> emacs -Q
> M-: (setq replace-char-fold t)
> C-x 8 ~ a RET
> M-<
> M-% a RET bbbb RET
> 
> The result of 'C-x 8 ~ a' (ã) is not highlighted as a match; it should
> be, as entering '!' will indeed replace ã with bbbb.
> 
> It should be noted that isearch in char-fold mode does highlight ã.
> 
> 
> In GNU Emacs 25.1.1 (x86_64-unknown-linux-gnu, GTK+ Version 3.20.7)
>  of 2016-08-21 built on lylat
> Windowing system distributor 'The X.Org Foundation', version 11.0.11804000
> System Description:	Debian GNU/Linux testing (stretch)
> 
> Configured features:
> XPM JPEG TIFF GIF PNG RSVG IMAGEMAGICK SOUND GPM DBUS GCONF GSETTINGS
> NOTIFY ACL LIBSELINUX GNUTLS LIBXML2 FREETYPE M17N_FLT LIBOTF XFT ZLIB
> TOOLKIT_SCROLL_BARS GTK3 X11
> 
> Important settings:
>   value of $LC_CTYPE: en_CA.utf8
>   value of $LANG: en_CA.utf8
>   locale-coding-system: utf-8-unix
> 
> Major mode: Lisp Interaction
> 
> Minor modes in effect:
>   tooltip-mode: t
>   global-eldoc-mode: t
>   electric-indent-mode: t
>   mouse-wheel-mode: t
>   tool-bar-mode: t
>   menu-bar-mode: t
>   file-name-shadow-mode: t
>   global-font-lock-mode: t
>   font-lock-mode: t
>   blink-cursor-mode: t
>   auto-composition-mode: t
>   auto-encryption-mode: t
>   auto-compression-mode: t
>   line-number-mode: t
>   transient-mark-mode: t
> 
> Load-path shadows:
> None found.

Closing, as this should now be fixed.

commit 9f9b56b7da323bc91cdde0bcc1e1863c523e7ee3
Date:   Tue Dec 26 12:46:39 2017 +0100

  Fix highlighting in query-replace with non-nil replace-char-fold

  * lisp/replace.el (replace-highlight): Bind
  'isearch-regexp-function' in the same way that function
  'replace-search' does, so as to respect the value of
  'replace-char-fold'.  (Bug#24356)

diff --git a/lisp/replace.el b/lisp/replace.el
index 80e5845..396428f 100644
--- a/lisp/replace.el
+++ b/lisp/replace.el
@@ -2212,7 +2212,10 @@ replace-highlight
   (if query-replace-lazy-highlight
       (let ((isearch-string search-string)
 	    (isearch-regexp regexp-flag)
-	    (isearch-regexp-function delimited-flag)
+	    (isearch-regexp-function (or delimited-flag
+					 (and replace-char-fold
+					      (not regexp-flag)
+					      #'char-fold-to-regexp)))
 	    (isearch-lax-whitespace
 	     replace-lax-whitespace)
 	    (isearch-regexp-lax-whitespace