re PR c++/51586 (ICE with invalid union)

	PR c++/51586
	* parser.c (cp_parser_check_class_key): Handle error_mark_node.

From-SVN: r182442

gcc/cp/ChangeLog

 2011-12-17  Jason Merrill  <jason@redhat.com>
 
+	PR c++/51586
+	* parser.c (cp_parser_check_class_key): Handle error_mark_node.
+
 	PR c++/51587
 	* decl.c (start_enum): Avoid using ENUM_UNDERLYING_TYPE on a
 	non-enum.

gcc/cp/parser.c

@@ -22624,6 +22624,8 @@ cp_parser_token_is_class_key (cp_token* token)
 static void
 cp_parser_check_class_key (enum tag_types class_key, tree type)
 {
+  if (type == error_mark_node)
+    return;
   if ((TREE_CODE (type) == UNION_TYPE) != (class_key == union_type))
     {
       permerror (input_location, "%qs tag used in naming %q#T",

gcc/testsuite/ChangeLog

 2011-12-17  Jason Merrill  <jason@redhat.com>
 
+	PR c++/51586
+	* g++.dg/lookup/nested2.C: New.
+
 	PR c++/51587
 	* g++.dg/parse/enum6.C: New.
 

gcc/testsuite/g++.dg/lookup/nested2.C

+// PR c++/51586
+
+union U
+{
+  union U { int i; };		// { dg-error "same name" }
+};