file_pat_to_reg_pat, buflist_findpat: const params

file_pat_to_reg_pat() and buflist_findpat() do not modify the data of
these parameters.

src/nvim/buffer.c

@@ -918,13 +918,15 @@ do_buffer (
 
   if (buf == NULL) {        /* could not find it */
     if (start == DOBUF_FIRST) {
-      /* don't warn when deleting */
-      if (!unload)
+      // don't warn when deleting
+      if (!unload) {
         EMSGN(_(e_nobufnr), count);
-    } else if (dir == FORWARD)
+      }
+    } else if (dir == FORWARD) {
       EMSG(_("E87: Cannot go beyond last buffer"));
-    else
+    } else {
       EMSG(_("E88: Cannot go before first buffer"));
+    }
     return FAIL;
   }
 
@@ -1711,18 +1713,15 @@ static buf_T *buflist_findname_file_id(char_u *ffname, FileID *file_id,
   return NULL;
 }
 
-/*
- * Find file in buffer list by a regexp pattern.
- * Return fnum of the found buffer.
- * Return < 0 for error.
- */
-int 
-buflist_findpat (
-    char_u *pattern,
-    char_u *pattern_end,       /* pointer to first char after pattern */
-    int unlisted,                   /* find unlisted buffers */
-    int diffmode,             /* find diff-mode buffers only */
-    int curtab_only                /* find buffers in current tab only */
+/// Find file in buffer list by a regexp pattern.
+/// Return fnum of the found buffer.
+/// Return < 0 for error.
+int buflist_findpat(
+    const char_u *pattern,
+    const char_u *pattern_end,  // pointer to first char after pattern
+    int unlisted,               // find unlisted buffers
+    int diffmode,               // find diff-mode buffers only
+    int curtab_only             // find buffers in current tab only
 )
 {
   int match = -1;

src/nvim/fileio.c

@@ -7096,26 +7096,23 @@ int match_file_list(char_u *list, char_u *sfname, char_u *ffname)
   return FALSE;
 }
 
-/*
- * Convert the given pattern "pat" which has shell style wildcards in it, into
- * a regular expression, and return the result in allocated memory.  If there
- * is a directory path separator to be matched, then TRUE is put in
- * allow_dirs, otherwise FALSE is put there -- webb.
- * Handle backslashes before special characters, like "\*" and "\ ".
- *
- * Returns NULL on failure.
- */
-char_u *
-file_pat_to_reg_pat (
-    char_u *pat,
-    char_u *pat_end,           /* first char after pattern or NULL */
-    char *allow_dirs,        /* Result passed back out in here */
-    int no_bslash             /* Don't use a backward slash as pathsep */
+/// Convert the given pattern "pat" which has shell style wildcards in it, into
+/// a regular expression, and return the result in allocated memory.  If there
+/// is a directory path separator to be matched, then TRUE is put in
+/// allow_dirs, otherwise FALSE is put there -- webb.
+/// Handle backslashes before special characters, like "\*" and "\ ".
+///
+/// Returns NULL on failure.
+char_u * file_pat_to_reg_pat(
+    const char_u *pat,
+    const char_u *pat_end,   // first char after pattern or NULL
+    char *allow_dirs,        // Result passed back out in here
+    int no_bslash            // Don't use a backward slash as pathsep
 )
 {
-  char_u      *endp;
+  const char_u *endp;
   char_u      *reg_pat;
-  char_u      *p;
+  const char_u *p;
   int nested = 0;
   int add_dollar = TRUE;
 

src/nvim/ops.c

@@ -703,18 +703,16 @@ char_u *get_expr_line_src(void)
 /// @param writing allow only writable registers
 bool valid_yank_reg(int regname, bool writing)
 {
-  if (       (regname > 0 && ASCII_ISALNUM(regname))
-             || (!writing && vim_strchr((char_u *)
-                     "/.%:="
-                     , regname) != NULL)
+  if ((regname > 0 && ASCII_ISALNUM(regname))
+      || (!writing && vim_strchr((char_u *) "/.%:=" , regname) != NULL)
       || regname == '#'
       || regname == '"'
       || regname == '-'
       || regname == '_'
       || regname == '*'
-             || regname == '+'
-             )
+      || regname == '+') {
     return true;
+  }
   return false;
 }
 
@@ -4666,8 +4664,9 @@ void write_reg_contents_ex(int name,
       int num = atoi((char *)str);
 
       buf = buflist_findnr(num);
-      if (buf == NULL)
+      if (buf == NULL) {
         EMSGN(_(e_nobufnr), (long)num);
+      }
     } else {
       buf = buflist_findnr(buflist_findpat(str, str + STRLEN(str),
                                            true, false, false));