DR 1558 PR c++/67021

	DR 1558
	PR c++/67021
	* pt.c (tsubst_decl) [TYPE_DECL]: Clear TYPE_DEPENDENT_P_VALID.

From-SVN: r226381

gcc/cp/ChangeLog

+2015-07-30  Jason Merrill  <jason@redhat.com>
+
+	DR 1558
+	PR c++/67021
+	* pt.c (tsubst_decl) [TYPE_DECL]: Clear TYPE_DEPENDENT_P_VALID.
+
 2015-07-28  Paolo Carlini  <paolo.carlini@oracle.com>
 
 	* call.c (build_op_delete_call, convert_like_real, build_over_call):

gcc/cp/pt.c

@@ -11570,6 +11570,10 @@ tsubst_decl (tree t, tree args, tsubst_flags_t complain)
 	  {
 	    DECL_ORIGINAL_TYPE (r) = NULL_TREE;
 	    set_underlying_type (r);
+	    if (TYPE_DECL_ALIAS_P (r) && type != error_mark_node)
+	      /* An alias template specialization can be dependent
+		 even if its underlying type is not.  */
+	      TYPE_DEPENDENT_P_VALID (TREE_TYPE (r)) = false;
 	  }
 
 	layout_decl (r, 0);

gcc/testsuite/g++.dg/cpp0x/alias-decl-52.C

+// PR c++/67021
+// { dg-do compile { target c++11 } }
+
+template<typename> struct Dummy;
+template<> struct Dummy<int> {};
+
+template <class...>
+struct all_same { static constexpr bool value = true; };
+template <class T, class...Rest>
+struct all_same<T, T, Rest...> : all_same<T, Rest...> {};
+template <class T, class U, class...Rest>
+struct all_same<T, U, Rest...> { static constexpr bool value = false; };
+
+template <class R>
+using ValueType = int;
+
+template <class I>
+constexpr bool A(I i) {
+  return all_same<ValueType<I>, ValueType<decltype(i++)>>::value;
+}
+
+int main() {
+  static_assert(A(42), "");
+}