cp_declarator *declarator;
cp_decl_specifier_seq decl_specs;
bool member_p;
+ const char *saved_message = NULL;
/* Look for the `using' keyword. */
cp_parser_require_keyword (parser, RID_USING, RT_USING);
attributes = cp_parser_attributes_opt (parser);
cp_parser_require (parser, CPP_EQ, RT_EQ);
+ /* Now we are going to parse the type-id of the declaration. */
+
+ /*
+ [dcl.type]/3 says:
+
+ "A type-specifier-seq shall not define a class or enumeration
+ unless it appears in the type-id of an alias-declaration (7.1.3) that
+ is not the declaration of a template-declaration."
+
+ In other words, if we currently are in an alias template, the
+ type-id should not define a type.
+
+ So let's set parser->type_definition_forbidden_message in that
+ case; cp_parser_check_type_definition (called by
+ cp_parser_class_specifier) will then emit an error if a type is
+ defined in the type-id. */
+ if (parser->num_template_parameter_lists)
+ {
+ saved_message = parser->type_definition_forbidden_message;
+ parser->type_definition_forbidden_message =
+ G_("types may not be defined in alias template declarations");
+ }
+
type = cp_parser_type_id (parser);
+
+ /* Restore the error message if need be. */
+ if (parser->num_template_parameter_lists)
+ parser->type_definition_forbidden_message = saved_message;
+
cp_parser_require (parser, CPP_SEMICOLON, RT_SEMICOLON);
if (cp_parser_error_occurred (parser))
--- /dev/null
+// Origin PR c++/51143
+// { dg-options "-std=c++11" }
+
+using A0 = struct B0 { void f() {} };
+
+template<int N>
+using A1 =
+ struct B1 { // { dg-error "types may not be defined in alias template" }
+ static auto constexpr value = N;
+ };
+
+A1<0> a1;
+
+template<class T>
+using A2 =
+ struct B2 { // { dg-error "types may not be defined in alias template" }
+ void f(T){}
+ };
+
+A2<bool> a2;
+
+template<class T>
+using A3 =
+ enum B3 {b = 0;}; //{ dg-error "types may not be defined in alias template" }
+
+A3<int> a3;
+
+int main() { }