re PR c++/51640 (Misleading error if the type in the catch() is ambiguous)

/cp
2014-05-16  Paolo Carlini  <paolo.carlini@oracle.com>

	PR c++/51640
	* parser.c (cp_parser_diagnose_invalid_type_name): Early return
	when cp_parser_lookup_name sets ambiguous_decls.

/testsuite
2014-05-16  Paolo Carlini  <paolo.carlini@oracle.com>

	PR c++/51640
	* g++.dg/parse/error54.C: New.

From-SVN: r210521

gcc/cp/ChangeLog

+2014-05-16  Paolo Carlini  <paolo.carlini@oracle.com>
+
+	PR c++/51640
+	* parser.c (cp_parser_diagnose_invalid_type_name): Early return
+	when cp_parser_lookup_name sets ambiguous_decls.
+
 2014-05-15  Jason Merrill  <jason@redhat.com>
 
 	* call.c (print_conversion_rejection): Use loc consistently.

gcc/cp/parser.c

@@ -2880,13 +2880,21 @@ cp_parser_diagnose_invalid_type_name (cp_parser *parser,
 				      tree scope, tree id,
 				      location_t location)
 {
-  tree decl, old_scope;
+  tree decl, old_scope, ambiguous_decls;
   cp_parser_commit_to_tentative_parse (parser);
   /* Try to lookup the identifier.  */
   old_scope = parser->scope;
   parser->scope = scope;
-  decl = cp_parser_lookup_name_simple (parser, id, location);
+  decl = cp_parser_lookup_name (parser, id, none_type,
+				/*is_template=*/false,
+				/*is_namespace=*/false,
+				/*check_dependency=*/true,
+				&ambiguous_decls, location);
   parser->scope = old_scope;
+  if (ambiguous_decls)
+    /* If the lookup was ambiguous, an error will already have
+       been issued.  */
+    return;
   /* If the lookup found a template-name, it means that the user forgot
   to specify an argument list. Emit a useful error message.  */
   if (TREE_CODE (decl) == TEMPLATE_DECL)

gcc/testsuite/ChangeLog

+2014-05-16  Paolo Carlini  <paolo.carlini@oracle.com>
+
+	PR c++/51640
+	* g++.dg/parse/error54.C: New.
+
 2014-05-16  Vladimir Makarov  <vmakarov@redhat.com>
 
 	PR rtl-optimization/60969

gcc/testsuite/g++.dg/parse/error54.C

+// PR c++/51640
+
+class ex {};
+
+namespace t
+{
+  class ex2 : public ex {};
+}
+
+class ex2 : public ex {};
+
+void bar()
+{
+  using namespace t;
+
+  try {
+  } catch (ex2&) { // { dg-error "reference to 'ex2' is ambiguous" }
+  }
+}