[C++ PATCH] For -std=c++1z treat class types with inherited ctors as non-aggregate (PR c++/79143, take 3)

[Jakub Jelinek <jakub at redhat dot com>]

On Wed, Feb 08, 2017 at 06:47:10PM -0500, Jason Merrill wrote:
> On Wed, Feb 8, 2017 at 5:24 PM, Jakub Jelinek <jakub@redhat.com> wrote:
> > On Wed, Feb 08, 2017 at 04:51:54PM -0500, Jason Merrill wrote:
> >> On Tue, Feb 7, 2017 at 4:30 PM, Jakub Jelinek <jakub@redhat.com> wrote:
> >> > P0017R1 added in [dcl.init.aggr]/1 that classes with inherited constructors
> >> > are not aggregate.  CLASSTYPE_NON_AGGREGATE is set slightly before
> >> > add_implicitly_declared_members is called and so we don't know about the
> >> > inherited ctors yet.
> >>
> >> Hmm, why doesn't my patch for 78124 to set CLASSTYPE_NON_AGGREGATE in
> >> do_class_using_decl cover this testcase?
> >
> > It does set CLASSTYPE_NON_AGGREGATE on a different RECORD_TYPE,
> > do_class_using_decl sees the template, while what is tested and what
> > check_bases_and_members is called on is the implicit instantiation thereof.
> >
> > The following completely untested patch also fixes it.  Or is there some
> > even better place where to copy over that bit from the template to the
> > instantiation?
> 
> Better I think in instantiate_class_template_1, about where we copy TYPE_PACKED.

That works too, bootstrapped/regtested on x86_64-linux and i686-linux, ok
for trunk?

2017-02-09  Jakub Jelinek  <jakub@redhat.com>
	    Jason Merrill  <jason@redhat.com>

	PR c++/79143
	* pt.c (instantiate_class_template_1): Copy CLASSTYPE_NON_AGGREGATE
	from pattern to type.

	* g++.dg/cpp1z/pr79143.C: New test.

--- gcc/cp/pt.c.jj	2017-02-06 21:02:40.000000000 +0100
+++ gcc/cp/pt.c	2017-02-09 00:57:58.961930210 +0100
@@ -10253,6 +10253,7 @@ instantiate_class_template_1 (tree type)
   TYPE_PACKED (type) = TYPE_PACKED (pattern);
   SET_TYPE_ALIGN (type, TYPE_ALIGN (pattern));
   TYPE_USER_ALIGN (type) = TYPE_USER_ALIGN (pattern);
+  CLASSTYPE_NON_AGGREGATE (type) = CLASSTYPE_NON_AGGREGATE (pattern);
   if (ANON_AGGR_TYPE_P (pattern))
     SET_ANON_AGGR_TYPE_P (type);
   if (CLASSTYPE_VISIBILITY_SPECIFIED (pattern))
--- gcc/testsuite/g++.dg/cpp1z/pr79143.C.jj	2017-02-07 17:55:19.091028200 +0100
+++ gcc/testsuite/g++.dg/cpp1z/pr79143.C	2017-02-07 17:54:48.000000000 +0100
@@ -0,0 +1,28 @@
+// PR c++/79143
+// { dg-do compile }
+// { dg-options "-std=c++1z" }
+
+struct base {
+  base (int, int) {}
+};
+
+template<class>
+struct derived : base {
+  using base::base;
+};
+
+template<class>
+struct derived2 : base {
+  derived2 (int x, int y) : base (x, y) {}
+};
+
+int
+main ()
+{
+  base (13, 42);
+  derived<int> (13, 42);
+  derived2<int> (13, 42);
+  base{13, 42};
+  derived<int>{13, 42}; // { dg-bogus "too many initializers" }
+  derived2<int>{13, 42};
+}


	Jakub