merge revision(s) 55562: [Backport #12454]

	* regcomp.c (noname_disable_map): don't optimize out group 0
	  Ruby's Regexp doesn't allow normal numbered groups if the regexp
	  has named groups. On such case it optimizes out related NT_ENCLOSE.
	  But even on the case it can use \g<0>.
	  This fix not to remove NT_ENCLOSE whose regnum is 0.
	  [ruby-core:75828] [Bug #12454]


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_3@55908 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 3 insertions, 4 deletions

diff --git a/regcomp.c b/regcomp.c
index 34b37f8e4c..c9583a3288 100644
--- a/regcomp.c
+++ b/regcomp.c
@@ -1876,17 +1876,16 @@ noname_disable_map(Node** plink, GroupNumRemap* map, int* counter)
 	  (*counter)++;
 	  map[en->regnum].new_val = *counter;
 	  en->regnum = *counter;
-	  r = noname_disable_map(&(en->target), map, counter);
 	}
-	else {
+	else if (en->regnum != 0) {
 	  *plink = en->target;
 	  en->target = NULL_NODE;
 	  onig_node_free(node);
 	  r = noname_disable_map(plink, map, counter);
+	  break;
 	}
       }
-      else
-	r = noname_disable_map(&(en->target), map, counter);
+      r = noname_disable_map(&(en->target), map, counter);
     }
     break;