PR c++/79580 - ICE with compound literal

	* parser.c (cp_parser_class_head): If we're in the middle of an
	expression, use ts_within_enclosing_non_class.

From-SVN: r245587

gcc/cp/ChangeLog

 2017-02-19  Jason Merrill  <jason@redhat.com>
 
+	PR c++/79580 - ICE with compound literal
+	* parser.c (cp_parser_class_head): If we're in the middle of an
+	expression, use ts_within_enclosing_non_class.
+
 	PR c++/79503 - inherited ctor taking base class
 	* call.c (add_function_candidate): Also check that
 	DECL_INHERITED_CTOR_BASE is reference-related to the parameter type.

gcc/cp/parser.c

@@ -22771,7 +22771,10 @@ cp_parser_class_head (cp_parser* parser,
       /* If the class was unnamed, create a dummy name.  */
       if (!id)
 	id = make_anon_name ();
-      type = xref_tag (class_key, id, /*tag_scope=*/ts_current,
+      tag_scope tag_scope = (parser->in_type_id_in_expr_p
+			     ? ts_within_enclosing_non_class
+			     : ts_current);
+      type = xref_tag (class_key, id, tag_scope,
 		       parser->num_template_parameter_lists);
     }
 

gcc/testsuite/g++.dg/ext/complit15.C

+// PR c++/79580
+// { dg-options "-flto -std=c++98" }
+
+class a
+{
+  static const double b;
+};
+const double a::b ((union { double c; }){}.c);