re PR c++/68724 (ice in unify, at cp/pt.c:19902)

	PR c++/68724
	* pt.c (unify): TRAIT_EXPR is an expr.

	PR c++/68724
	* g++.dg/cpp0x/pr68724.C: New.

From-SVN: r239167

gcc/cp/ChangeLog

+2016-08-05  Nathan Sidwell  <nathan@acm.org>
+
+	PR c++/68724
+	* pt.c (unify): TRAIT_EXPR is an expr.
+
 2016-08-04  Paolo Carlini  <paolo.carlini@oracle.com>
 
 	PR c++/72800

gcc/cp/pt.c

@@ -20269,7 +20269,7 @@ unify (tree tparms, tree targs, tree parm, tree arg, int strict,
       /* An unresolved overload is a nondeduced context.  */
       if (is_overloaded_fn (parm) || type_unknown_p (parm))
 	return unify_success (explain_p);
-      gcc_assert (EXPR_P (parm));
+      gcc_assert (EXPR_P (parm) || TREE_CODE (parm) == TRAIT_EXPR);
     expr:
       /* We must be looking at an expression.  This can happen with
 	 something like:

gcc/testsuite/ChangeLog

+2016-08-05  Nathan Sidwell  <nathan@acm.org>
+
+	PR c++/68724
+	* g++.dg/cpp0x/pr68724.C: New.
+
 2016-08-05  Richard Biener  <rguenther@suse.de>
 
 	* gcc.dg/tree-ssa/ivopt_5.c: Make robust against edge swapping.

gcc/testsuite/g++.dg/cpp0x/pr68724.C

+// PR 68724 ICE in  unificiation
+// { dg-do compile { target c++11 } }
+
+template <typename _Tp, _Tp>
+struct integral_constant
+{
+};
+
+integral_constant<bool, true> inst;
+
+template <typename _Tp>
+struct integral_constant<bool, __is_enum(_Tp)> // { dg-error "" }
+{
+};
+