patch 8.1.2113: ":help expr-!~?" only works after searchingv8.1.2113

Problem:    ":help expr-!~?" only works after searching.
Solution:   Escape "~" after "expr-". (closes #5015)

1 files changed, 13 insertions, 3 deletions

diff --git a/src/ex_cmds.c b/src/ex_cmds.c
index 85e5be066d..da01e9ddad 100644
--- a/src/ex_cmds.c
+++ b/src/ex_cmds.c
@@ -5547,12 +5547,22 @@ find_help_tags(
     if (STRNICMP(arg, "expr-", 5) == 0)
     {
 	// When the string starting with "expr-" and containing '?' and matches
-	// the table, it is taken literally.  Otherwise '?' is recognized as a
-	// wildcard.
+	// the table, it is taken literally (but ~ is escaped).  Otherwise '?'
+	// is recognized as a wildcard.
 	for (i = (int)(sizeof(expr_table) / sizeof(char *)); --i >= 0; )
 	    if (STRCMP(arg + 5, expr_table[i]) == 0)
 	    {
-		STRCPY(d, arg);
+		int si = 0, di = 0;
+
+		for (;;)
+		{
+		    if (arg[si] == '~')
+			d[di++] = '\\';
+		    d[di++] = arg[si];
+		    if (arg[si] == NUL)
+			break;
+		    ++si;
+		}
 		break;
 	    }
     }