PR c++/80241 - ICE with alignas pack expansion.

	* error.c (dump_expr): Handle TREE_LIST.
	* parser.c (cp_parser_std_attribute_list): Return error_mark if
	make_pack_expansion returns an error.

	* g++.dg/cpp0x/alignas11.C: New test.

From-SVN: r246963

gcc/cp/ChangeLog

@@ -3,6 +3,11 @@
 	PR c++/80244 - ICE with attribute in template alias.
 	* tree.c (strip_typedefs): Handle UNDERLYING_TYPE.
 
+	PR c++/80241 - ICE with alignas pack expansion.
+	* error.c (dump_expr): Handle TREE_LIST.
+	* parser.c (cp_parser_std_attribute_list): Return error_mark if
+	make_pack_expansion returns an error.
+
 2017-04-17  Bernd Edlinger  <bernd.edlinger@hotmail.de>
 
 	PR c++/80287

gcc/cp/error.c

@@ -2822,6 +2822,10 @@ dump_expr (cxx_pretty_printer *pp, tree t, int flags)
       pp_string (pp, M_("*this"));
       break;
 
+    case TREE_LIST:
+      dump_expr_list (pp, t, flags);
+      break;
+
       /*  This list is incomplete, but should suffice for now.
 	  It is very important that `sorry' does not call
 	  `report_error_function'.  That could cause an infinite loop.  */

gcc/cp/parser.c

@@ -24846,8 +24846,12 @@ cp_parser_std_attribute_list (cp_parser *parser, tree attr_ns)
 	    error_at (token->location,
 		      "expected attribute before %<...%>");
 	  else
-	    TREE_VALUE (attribute)
-	      = make_pack_expansion (TREE_VALUE (attribute));
+	    {
+	      tree pack = make_pack_expansion (TREE_VALUE (attribute));
+	      if (pack == error_mark_node)
+		return error_mark_node;
+	      TREE_VALUE (attribute) = pack;
+	    }
 	  token = cp_lexer_peek_token (parser->lexer);
 	}
       if (token->type != CPP_COMMA)

gcc/testsuite/ChangeLog

@@ -3,6 +3,9 @@
 	PR c++/80244 - ICE with attribute in template alias.
 	* g++.dg/cpp0x/alias-decl-59.C: New test.
 
+	PR c++/80241 - ICE with alignas pack expansion.
+	* g++.dg/cpp0x/alignas11.C: New test.
+
 2017-04-17  Bernd Edlinger  <bernd.edlinger@hotmail.de>
 
 	PR c++/80287

gcc/testsuite/g++.dg/cpp0x/alignas11.C

+// PR c++/80241
+// { dg-do compile { target c++11 } }
+
+template <typename... T>
+struct A
+{
+  [[gnu::aligned (alignof(A))...]] char c; // { dg-error "expansion pattern" }
+};
+
+A<int> a;