diff --git a/ChangeLog b/ChangeLog
index 51c2c359089e34..4b82b9f7f98f34 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Sat Nov 29 19:19:32 2008  Yukihiro Matsumoto  <matz@ruby-lang.org>
+
+	* regparse.c (is_invalid_quantifier_target): Perl and old Ruby
+	  accepts quantifier on anchors.  [ruby-core:20161]
+
 Sat Nov 29 00:18:30 2008  Yukihiro Matsumoto  <matz@ruby-lang.org>
 
 	* cont.c (fiber_alloc): separate allocation and initialization.
diff --git a/regparse.c b/regparse.c
index c7b42eaf743134..8a02966def292b 100644
--- a/regparse.c
+++ b/regparse.c
@@ -2112,6 +2112,7 @@ conv_backslash_value(int c, ScanEnv* env)
   return c;
 }
 
+#if 0				/* no invalid quantifier */
 static int
 is_invalid_quantifier_target(Node* node)
 {
@@ -2143,6 +2144,9 @@ is_invalid_quantifier_target(Node* node)
   }
   return 0;
 }
+#else
+#define is_invalid_quantifier_target(node) 0
+#endif
 
 /* ?:0, *:1, +:2, ??:3, *?:4, +?:5 */
 static int
diff --git a/test/ruby/test_regexp.rb b/test/ruby/test_regexp.rb
index fdfef04b4d5d7e..d6441c9573c7a6 100644
--- a/test/ruby/test_regexp.rb
+++ b/test/ruby/test_regexp.rb
@@ -604,11 +604,13 @@ def test_parse_curly_brace
     check(/\Aa{0}+\z/, "", %w(a aa aab))
     check(/\Aa{1}+\z/, %w(a aa), ["", "aab"])
     check(/\Aa{1,2}b{1,2}\z/, %w(ab aab abb aabb), ["", "aaabb", "abbb"])
+    check(/(?!x){0,1}/, [ ['', 'ab'], ['', ''] ])
+    check(/c\z{0,1}/, [ ['c', 'abc'], ['c', 'cab']], ['abd'])
+    check(/\A{0,1}a/, [ ['a', 'abc'], ['a', '____abc']], ['bcd'])
     failcheck('.{100001}')
     failcheck('.{0,100001}')
     failcheck('.{1,0}')
     failcheck('{0}')
-    failcheck('(?!x){0,1}')
   end
 
   def test_parse_comment