PR c++/78198 - inherited template ctor with default arg

	* call.c (convert_default_arg): Look through inheriting ctors.

From-SVN: r241843

gcc/cp/ChangeLog

+2016-11-03  Jason Merrill  <jason@redhat.com>
+
+	PR c++/78198
+	* call.c (convert_default_arg): Look through inheriting ctors.
+
 2016-11-03  Jakub Jelinek  <jakub@redhat.com>
 	    Alexandre Oliva  <aoliva@redhat.com>
 	    Jason Merrill  <jason@redhat.com>

gcc/cp/call.c

@@ -7193,6 +7193,9 @@ convert_default_arg (tree type, tree arg, tree fn, int parmnum,
 
   /* See through clones.  */
   fn = DECL_ORIGIN (fn);
+  /* And inheriting ctors.  */
+  if (flag_new_inheriting_ctors)
+    fn = strip_inheriting_ctors (fn);
 
   /* Detect recursion.  */
   FOR_EACH_VEC_SAFE_ELT (default_arg_context, i, t)

gcc/testsuite/g++.dg/cpp0x/inh-ctor22.C

+// { dg-do compile { target c++11 } }
+
+class A { };
+template<typename> using UniquePtr = int;
+template<typename AllocPolicy> struct BufferList {
+  BufferList(unsigned, unsigned, unsigned, AllocPolicy = AllocPolicy());
+};
+class D : BufferList<A> {
+  using BufferList::BufferList;
+};
+template<typename , typename... Args> UniquePtr<D> MakeUnique(Args... aArgs)
+{
+  D d(aArgs...);
+  return 0;
+}
+UniquePtr<D> setCloneBuffer_impl_buf = MakeUnique<D>(0, 0, 0);