vim-patch:8.2.0502: Vim9: some code is not tested

Problem:    Vim9: some code is not tested.
Solution:   Add more tests.  Fix uncovered problems.

e8c4abbbd7

Co-authored-by: Bram Moolenaar <Bram@vim.org>

src/nvim/cmdexpand.c

@@ -1246,7 +1246,7 @@ static const char *set_context_by_cmdname(const char *cmd, cmdidx_T cmdidx, cons
       arg = (const char *)skipwhite(skiptowhite(arg));
       if (*arg != NUL) {
         xp->xp_context = EXPAND_NOTHING;
-        arg = (const char *)skip_regexp((char *)arg + 1, (uint8_t)(*arg), p_magic, NULL);
+        arg = (const char *)skip_regexp((char *)arg + 1, (uint8_t)(*arg), p_magic);
       }
     }
     return (const char *)find_nextcmd(arg);
@@ -1285,7 +1285,7 @@ static const char *set_context_by_cmdname(const char *cmd, cmdidx_T cmdidx, cons
     if (delim) {
       // Skip "from" part.
       arg++;
-      arg = (const char *)skip_regexp((char *)arg, delim, p_magic, NULL);
+      arg = (const char *)skip_regexp((char *)arg, delim, p_magic);
     }
     // Skip "to" part.
     while (arg[0] != NUL && (uint8_t)arg[0] != delim) {

src/nvim/eval/userfunc.c

@@ -1964,7 +1964,7 @@ void ex_function(exarg_T *eap)
 
   // ":function /pat": list functions matching pattern.
   if (*eap->arg == '/') {
-    p = skip_regexp(eap->arg + 1, '/', true, NULL);
+    p = skip_regexp(eap->arg + 1, '/', true);
     if (!eap->skip) {
       regmatch_T regmatch;
 

src/nvim/ex_cmds.c

@@ -504,7 +504,7 @@ void ex_sort(exarg_T *eap)
       eap->nextcmd = check_nextcmd(p);
       break;
     } else if (!ASCII_ISALPHA(*p) && regmatch.regprog == NULL) {
-      s = skip_regexp(p + 1, *p, true, NULL);
+      s = skip_regexp(p + 1, *p, true);
       if (*s != *p) {
         emsg(_(e_invalpat));
         goto sortend;
@@ -3503,7 +3503,7 @@ static int do_sub(exarg_T *eap, proftime_T timeout, long cmdpreview_ns, handle_T
       which_pat = RE_LAST;                  // use last used regexp
       delimiter = (char_u)(*cmd++);                   // remember delimiter character
       pat = cmd;                            // remember start of search pat
-      cmd = skip_regexp(cmd, delimiter, p_magic, &eap->arg);
+      cmd = skip_regexp_ex(cmd, delimiter, p_magic, &eap->arg, NULL);
       if (cmd[0] == delimiter) {            // end delimiter found
         *cmd++ = NUL;                       // replace it with a NUL
         has_second_delim = true;
@@ -4536,7 +4536,7 @@ void ex_global(exarg_T *eap)
     delim = *cmd;               // get the delimiter
     cmd++;                      // skip delimiter if there is one
     pat = cmd;                  // remember start of pattern
-    cmd = skip_regexp(cmd, delim, p_magic, &eap->arg);
+    cmd = skip_regexp_ex(cmd, delim, p_magic, &eap->arg, NULL);
     if (cmd[0] == delim) {                  // end delimiter found
       *cmd++ = NUL;                         // replace it with a NUL
     }
@@ -4849,7 +4849,7 @@ char *skip_vimgrep_pat(char *p, char **s, int *flags)
       *s = p + 1;
     }
     c = (char_u)(*p);
-    p = skip_regexp(p + 1, c, true, NULL);
+    p = skip_regexp(p + 1, c, true);
     if (*p != c) {
       return NULL;
     }

src/nvim/ex_docmd.c

@@ -3351,7 +3351,7 @@ static linenr_T get_address(exarg_T *eap, char **ptr, cmd_addr_T addr_type, int
         goto error;
       }
       if (skip) {                       // skip "/pat/"
-        cmd = skip_regexp(cmd, c, p_magic, NULL);
+        cmd = skip_regexp(cmd, c, p_magic);
         if (*cmd == c) {
           cmd++;
         }
@@ -6494,7 +6494,7 @@ static void ex_findpat(exarg_T *eap)
   if (*eap->arg == '/') {   // Match regexp, not just whole words
     whole = false;
     eap->arg++;
-    char *p = skip_regexp(eap->arg, '/', p_magic, NULL);
+    char *p = skip_regexp(eap->arg, '/', p_magic);
     if (*p) {
       *p++ = NUL;
       p = skipwhite(p);

src/nvim/ex_eval.c

@@ -1296,7 +1296,7 @@ void ex_catch(exarg_T *eap)
     eap->nextcmd = find_nextcmd(eap->arg);
   } else {
     pat = eap->arg + 1;
-    end = skip_regexp(pat, *eap->arg, true, NULL);
+    end = skip_regexp(pat, *eap->arg, true);
   }
 
   if (!give_up) {

src/nvim/ex_getln.c

@@ -314,7 +314,7 @@ static bool do_incsearch_highlighting(int firstc, int *search_delim, incsearch_s
   p = skipwhite(p);
   delim = (delim_optional && vim_isIDc(*p)) ? ' ' : *p++;
   *search_delim = delim;
-  end = skip_regexp(p, delim, p_magic, NULL);
+  end = skip_regexp(p, delim, p_magic);
 
   use_last_pat = end == p && *end == delim;
   if (end == p && !use_last_pat) {

src/nvim/match.c

@@ -1206,7 +1206,7 @@ void ex_match(exarg_T *eap)
       semsg(_(e_invarg2), eap->arg);
       return;
     }
-    end = skip_regexp(p + 1, *p, true, NULL);
+    end = skip_regexp(p + 1, *p, true);
     if (!eap->skip) {
       if (*end != NUL && !ends_excmd(*skipwhite(end + 1))) {
         xfree(g);

src/nvim/regexp.c

@@ -484,10 +484,17 @@ static char_u *skip_anyof(char *p)
 /// Stop at end of "startp" or where "dirc" is found ('/', '?', etc).
 /// Take care of characters with a backslash in front of it.
 /// Skip strings inside [ and ].
+char *skip_regexp(char *startp, int dirc, int magic)
+{
+  return skip_regexp_ex(startp, dirc, magic, NULL, NULL);
+}
+
+/// skip_regexp() with extra arguments:
 /// When "newp" is not NULL and "dirc" is '?', make an allocated copy of the
 /// expression and change "\?" to "?".  If "*newp" is not NULL the expression
 /// is changed in-place.
-char *skip_regexp(char *startp, int dirc, int magic, char **newp)
+/// If a "\?" is changed to "?" then "dropped" is incremented, unless NULL.
+char *skip_regexp_ex(char *startp, int dirc, int magic, char **newp, int *dropped)
 {
   int mymagic;
   char *p = startp;
@@ -516,6 +523,9 @@ char *skip_regexp(char *startp, int dirc, int magic, char **newp)
           *newp = xstrdup(startp);
           p = *newp + (p - startp);
         }
+        if (dropped != NULL) {
+          (*dropped)++;
+        }
         STRMOVE(p, p + 1);
       } else {
         p++;            // skip next character

src/nvim/search.c

@@ -1080,7 +1080,7 @@ int do_search(oparg_T *oap, int dirc, int search_delim, char_u *pat, long count,
       // Find end of regular expression.
       // If there is a matching '/' or '?', toss it.
       ps = (char_u *)strcopy;
-      p = (char_u *)skip_regexp((char *)pat, search_delim, p_magic, &strcopy);
+      p = (char_u *)skip_regexp_ex((char *)pat, search_delim, p_magic, &strcopy, NULL);
       if (strcopy != (char *)ps) {
         // made a copy of "pat" to change "\?" to "?"
         searchcmdlen += (int)(STRLEN(pat) - strlen(strcopy));

src/nvim/syntax.c

@@ -4749,7 +4749,7 @@ static char *get_syn_pattern(char *arg, synpat_T *ci)
     return NULL;
   }
 
-  end = skip_regexp(arg + 1, *arg, true, NULL);
+  end = skip_regexp(arg + 1, *arg, true);
   if (*end != *arg) {                       // end delimiter not found
     semsg(_("E401: Pattern delimiter not found: %s"), arg);
     return NULL;
@@ -4902,7 +4902,7 @@ static void syn_cmd_sync(exarg_T *eap, int syncing)
         finished = true;
         break;
       }
-      arg_end = skip_regexp(next_arg + 1, *next_arg, true, NULL);
+      arg_end = skip_regexp(next_arg + 1, *next_arg, true);
       if (*arg_end != *next_arg) {          // end delimiter not found
         illegal = true;
         break;

src/nvim/tag.c

@@ -2670,7 +2670,7 @@ static int jumpto_tag(const char_u *lbuf_arg, int forceit, int keep_help)
     // anything following.
     str = pbuf;
     if (pbuf[0] == '/' || pbuf[0] == '?') {
-      str = (char_u *)skip_regexp((char *)pbuf + 1, pbuf[0], false, NULL) + 1;
+      str = (char_u *)skip_regexp((char *)pbuf + 1, pbuf[0], false) + 1;
     }
     if (str > pbuf_end - 1) {   // search command with nothing following
       save_p_ws = p_ws;
@@ -2883,7 +2883,7 @@ static int find_extra(char_u **pp)
     if (ascii_isdigit(*str)) {
       str = (char_u *)skipdigits((char *)str + 1);
     } else if (*str == '/' || *str == '?') {
-      str = (char_u *)skip_regexp((char *)str + 1, *str, false, NULL);
+      str = (char_u *)skip_regexp((char *)str + 1, *str, false);
       if (*str != first_char) {
         str = NULL;
       } else {