Add clarifying comment to toke.c

diff --git a/toke.c b/toke.c
index d7d5d4d..8cbe28a 100644 (file)
--- a/toke.c
+++ b/toke.c
@@ -2811,7 +2811,8 @@ S_scan_const(pTHX_ char *start)
 
            s++;
 
-           /* deprecate \1 in strings and substitution replacements */
+           /* warn on \1 - \9 in substitution replacements, but note that \11
+            * is an octal; and \19 is \1 followed by '9' */
            if (PL_lex_inwhat == OP_SUBST && !PL_lex_inpat &&
                isDIGIT(*s) && *s != '0' && !isDIGIT(s[1]))
            {