Handle chars of syntax word which are also flagged as comment delimiters

src/syntax.c (scan_sexps_forward): When chars of syntax word are also flagged
as the start/end of two char comment delimiters, recognize a comment delimiter
in preference to a portion of a word.  This fixes bug #24767.

1 files changed, 20 insertions, 3 deletions

diff --git a/src/syntax.c b/src/syntax.c
index 667de402ec4..d463f7e93db 100644
--- a/src/syntax.c
+++ b/src/syntax.c
@@ -3124,6 +3124,7 @@ scan_sexps_forward (struct lisp_parse_state *state,
   ptrdiff_t prev_from;          /* Keep one character before FROM.  */
   ptrdiff_t prev_from_byte;
   int prev_from_syntax, prev_prev_from_syntax;
+  int syntax;
   bool boundary_stop = commentstop == -1;
   bool nofence;
   bool found;
@@ -3191,8 +3192,6 @@ do { prev_from = from;				\
 
   while (from < end)
     {
-      int syntax;
-
       if (SYNTAX_FLAGS_COMSTART_FIRST (prev_from_syntax)
           && (c1 = FETCH_CHAR (from_byte),
               syntax = SYNTAX_WITH_FLAGS (c1),
@@ -3258,7 +3257,24 @@ do { prev_from = from;				\
           while (from < end)
             {
               int symchar = FETCH_CHAR_AS_MULTIBYTE (from_byte);
-              switch (SYNTAX (symchar))
+
+              if (SYNTAX_FLAGS_COMSTART_FIRST (prev_from_syntax)
+                  && (syntax = SYNTAX_WITH_FLAGS (symchar),
+                      SYNTAX_FLAGS_COMSTART_SECOND (syntax)))
+                {
+                  state->comstyle
+                    = SYNTAX_FLAGS_COMMENT_STYLE (syntax, prev_from_syntax);
+                  comnested = (SYNTAX_FLAGS_COMMENT_NESTED (prev_from_syntax)
+                               | SYNTAX_FLAGS_COMMENT_NESTED (syntax));
+                  state->incomment = comnested ? 1 : -1;
+                  state->comstr_start = prev_from;
+                  INC_FROM;
+                  prev_from_syntax = Smax;
+                  code = Scomment;
+                  goto atcomment;
+                }
+
+              switch (SYNTAX (symchar))
                 {
                 case Scharquote:
                 case Sescape:
@@ -3280,6 +3296,7 @@ do { prev_from = from;				\
 
         case Scomment_fence: /* Can't happen because it's handled above.  */
         case Scomment:
+        atcomment:
           if (commentstop || boundary_stop) goto done;
         startincomment:
           /* The (from == BEGV) test was to enter the loop in the middle so