PR c++/84798 - ICE with auto in abstract function declarator.

	* parser.c (cp_parser_parameter_declaration_clause): Check
	parser->default_arg_ok_p.

From-SVN: r258493

gcc/cp/ChangeLog

+2018-03-13  Jason Merrill  <jason@redhat.com>
+
+	PR c++/84798 - ICE with auto in abstract function declarator.
+	* parser.c (cp_parser_parameter_declaration_clause): Check
+	parser->default_arg_ok_p.
+
 2018-03-13  Jakub Jelinek  <jakub@redhat.com>
 
 	PR c++/84808

gcc/cp/parser.c

@@ -21198,7 +21198,10 @@ cp_parser_parameter_declaration_clause (cp_parser* parser)
 
   if (!processing_specialization
       && !processing_template_parmlist
-      && !processing_explicit_instantiation)
+      && !processing_explicit_instantiation
+      /* default_arg_ok_p tracks whether this is a parameter-clause for an
+         actual function or a random abstract declarator.  */
+      && parser->default_arg_ok_p)
     if (!current_function_decl
 	|| (current_class_type && LAMBDA_TYPE_P (current_class_type)))
       parser->auto_is_implicit_function_template_parm_p = true;

gcc/testsuite/g++.dg/cpp0x/auto51.C

+// PR c++/84798
+// { dg-do compile { target c++11 } }
+
+template<typename T>
+struct S {
+    static constexpr T value = 0;
+};
+
+constexpr auto x = S<void(*)(auto)>::value; // { dg-error "auto" }

gcc/testsuite/g++.dg/cpp1y/pr60393.C

 // PR c++/60393
 // { dg-do compile { target c++14 } }
-// { dg-options "" }
 
-void (*f)(auto) + 0; // { dg-error "expected" }
+void (*f)(auto) + 0; // { dg-error "auto|expected" }
 
 struct A
 {