OK.
On Tue, May 29, 2018 at 10:55 AM, Jakub Jelinek <ja...@redhat.com> wrote:
> On Tue, May 29, 2018 at 10:49:03AM -0400, Jason Merrill wrote:
>> >> auto & [x,y] = a;
>> >>
>> >> but that should be added to the testcase.
>> >
>> > It is already there (in baz).
>>
>> Well, yes, but in baz a is an S, not an array; I see value and
>> reference cases for S, but only value for int array.
>
> Oops, yes, you're right. Added qux then that tests array initializer
> and & qualifier.
>
> Ok with that change?
>
> 2018-05-29 Jakub Jelinek <ja...@redhat.com>
>
> PR c++/85952
> * init.c (build_aggr_init): For structured binding initialized from
> array call mark_rvalue_use on the initializer.
>
> * g++.dg/warn/Wunused-var-33.C: New test.
>
> --- gcc/cp/init.c.jj 2018-05-25 14:34:41.000000000 +0200
> +++ gcc/cp/init.c 2018-05-28 19:04:10.504063972 +0200
> @@ -1678,6 +1678,7 @@ build_aggr_init (tree exp, tree init, in
> if (VAR_P (exp) && DECL_DECOMPOSITION_P (exp))
> {
> from_array = 1;
> + init = mark_rvalue_use (init);
> if (init && DECL_P (init)
> && !(flags & LOOKUP_ONLYCONVERTING))
> {
> --- gcc/testsuite/g++.dg/warn/Wunused-var-33.C.jj 2018-05-28
> 19:32:00.236440573 +0200
> +++ gcc/testsuite/g++.dg/warn/Wunused-var-33.C 2018-05-29 16:52:21.322700629
> +0200
> @@ -0,0 +1,37 @@
> +// PR c++/85952
> +// { dg-do compile { target c++11 } }
> +// { dg-options "-Wunused-but-set-variable" }
> +
> +int
> +foo ()
> +{
> + int a[2] = {1, 2}; // { dg-bogus "set but not used" } */
> + auto [x, y] = a; // { dg-warning "structured bindings only available
> with" "" { target c++14_down } }
> + return x + y;
> +}
> +
> +struct S { int d, e; };
> +
> +int
> +bar ()
> +{
> + S a = {1, 2};
> + auto [x, y] = a; // { dg-warning "structured bindings only available
> with" "" { target c++14_down } }
> + return x + y;
> +}
> +
> +int
> +baz ()
> +{
> + S a = {1, 2};
> + auto & [x, y] = a; // { dg-warning "structured bindings only available
> with" "" { target c++14_down } }
> + return x + y;
> +}
> +
> +int
> +qux ()
> +{
> + int a[2] = {1, 2};
> + auto & [x, y] = a; // { dg-warning "structured bindings only available
> with" "" { target c++14_down } }
> + return x + y;
> +}
>
> Jakub
