On Sun, Nov 18, 2018 at 08:33:39PM -0500, Jason Merrill wrote:
> On Fri, Nov 16, 2018 at 4:26 PM Jakub Jelinek <ja...@redhat.com> wrote:
> > I admit this is just a shot in the dark, but I don't see why
> > one couldn't adjust a type of EMPTY_CLASS_EXPR to EMPTY_CLASS_EXPR
> > with a different variant of the same type.
>
> Makes sense.
>
> > Or, should I drop that
> > && TYPE_MAIN_VARIANT (type) == TYPE_MAIN_VARIANT (TREE_TYPE (temp))
> > part? We don't really verify something similar for CONSTRUCTORs.
>
> I suppose it makes sense to assert
> same_type_ignoring_top_level_qualifiers_p for both CONSTRUCTOR and
> EMPTY_CLASS_EXPR. OK with that change.
Unfortunately that regresses
+FAIL: g++.dg/cpp2a/lambda-uneval8.C -std=c++2a (internal compiler error)
+FAIL: g++.dg/cpp2a/lambda-uneval8.C -std=c++2a (test for excess errors)
where one adjust_temp_type call is with
struct A<<lambda closure object><lambda()>()>
as type and a different (including different TYPE_MAIN_VARIANT)
TREE_TYPE (temp), also with printable name
struct A<<lambda closure object><lambda()>()>.
Shall I remove those asserts for now then, or hand it over to you (no idea
what's going on there)?
2018-11-19 Jakub Jelinek <ja...@redhat.com>
PR c++/87506
* constexpr.c (adjust_temp_type): Handle EMPTY_CLASS_EXPR.
Add assertions for the CONSTRUCTOR case.
* g++.dg/cpp0x/constexpr-87506.C: New test.
--- gcc/cp/constexpr.c.jj 2018-11-16 21:35:34.551110868 +0100
+++ gcc/cp/constexpr.c 2018-11-19 09:35:06.880386449 +0100
@@ -1280,7 +1280,17 @@ adjust_temp_type (tree type, tree temp)
return temp;
/* Avoid wrapping an aggregate value in a NOP_EXPR. */
if (TREE_CODE (temp) == CONSTRUCTOR)
- return build_constructor (type, CONSTRUCTOR_ELTS (temp));
+ {
+ gcc_assert (same_type_ignoring_top_level_qualifiers_p (TREE_TYPE (temp),
+ type));
+ return build_constructor (type, CONSTRUCTOR_ELTS (temp));
+ }
+ if (TREE_CODE (temp) == EMPTY_CLASS_EXPR)
+ {
+ gcc_assert (same_type_ignoring_top_level_qualifiers_p (TREE_TYPE (temp),
+ type));
+ return build0 (EMPTY_CLASS_EXPR, type);
+ }
gcc_assert (scalarish_type_p (type));
return cp_fold_convert (type, temp);
}
--- gcc/testsuite/g++.dg/cpp0x/constexpr-87506.C.jj 2018-11-19
09:33:07.795341369 +0100
+++ gcc/testsuite/g++.dg/cpp0x/constexpr-87506.C 2018-11-19
09:33:07.795341369 +0100
@@ -0,0 +1,12 @@
+// PR c++/87506
+// { dg-do compile { target c++11 } }
+
+struct A {};
+struct B { constexpr B (const A) {} };
+struct C : B { using B::B; };
+
+void
+foo ()
+{
+ C c (A{});
+}
>
> Jason
Jakub
