Hi,
in this error recovery issue get_underlying_template crashes when
TYPE_TEMPLATE_INFO_MAYBE_ALIAS is applied to a null orig_type. Simply
checking for that condition appears to solve the issue in a
straightforward way. Tested x86_64-linux.
Thanks, Paolo.
/////////////////////
/cp
2017-01-13 Paolo Carlini <paolo.carl...@oracle.com>
PR c++/71737
* pt.c (get_underlying_template): Don't crash if orig_type
is NULL_TREE.
/testsuite
2017-01-13 Paolo Carlini <paolo.carl...@oracle.com>
PR c++/71737
* g++.dg/cpp0x/pr71737.C: New.
Index: cp/pt.c
===================================================================
--- cp/pt.c (revision 244405)
+++ cp/pt.c (working copy)
@@ -5916,6 +5916,8 @@ get_underlying_template (tree tmpl)
{
/* Determine if the alias is equivalent to an underlying template. */
tree orig_type = DECL_ORIGINAL_TYPE (DECL_TEMPLATE_RESULT (tmpl));
+ if (!orig_type)
+ break;
tree tinfo = TYPE_TEMPLATE_INFO_MAYBE_ALIAS (orig_type);
if (!tinfo)
break;
Index: testsuite/g++.dg/cpp0x/pr71737.C
===================================================================
--- testsuite/g++.dg/cpp0x/pr71737.C (revision 0)
+++ testsuite/g++.dg/cpp0x/pr71737.C (working copy)
@@ -0,0 +1,13 @@
+// PR c++/78765
+// { dg-do compile { target c++11 } }
+
+template <template <typename ...> class TT>
+struct quote {
+ template <typename ...Ts>
+ using apply = TT<Ts...>; // { dg-error "pack expansion" }
+};
+
+template <typename>
+using to_int_t = int;
+
+using t = quote<quote<to_int_t>::apply>::apply<int>;
