OK.
On Thu, Apr 5, 2018 at 5:09 PM, Jakub Jelinek <ja...@redhat.com> wrote:
> Hi!
>
> For cp_finish_decomp we require that the id decl for the structured binding
> are chained together, because we pass just the artificial underlying decl
> and first id and cp_finish_decomp walks DECL_CHAIN to find other ids.
> tsubst_decomp_names was actually requiring not just that, but also that
> the artificial undering decl follows the last id, which is unnecessary and
> isn't actually true if the initializer has some lambdas in it, because those
> might appear in between.
>
> Fixed thusly, bootstrapped/regtested on x86_64-linux and i686-linux, ok for
> trunk?
>
> 2018-04-05 Jakub Jelinek <ja...@redhat.com>
>
> PR c++/85209
> * pt.c (tsubst_decomp_names): Don't fail or ICE if DECL_CHAIN (decl3)
> is not prev, if prev == decl.
>
> * g++.dg/cpp1z/decomp39.C: New test.
> * g++.dg/cpp1z/decomp40.C: New test.
>
> --- gcc/cp/pt.c.jj 2018-04-05 09:49:06.155459292 +0200
> +++ gcc/cp/pt.c 2018-04-05 15:02:40.290261785 +0200
> @@ -16230,7 +16230,8 @@ tsubst_decomp_names (tree decl, tree pat
> if (error_operand_p (decl3))
> decl = error_mark_node;
> else if (decl != error_mark_node
> - && DECL_CHAIN (decl3) != prev)
> + && DECL_CHAIN (decl3) != prev
> + && decl != prev)
> {
> gcc_assert (errorcount);
> decl = error_mark_node;
> --- gcc/testsuite/g++.dg/cpp1z/decomp39.C.jj 2018-04-05 15:10:17.053265429
> +0200
> +++ gcc/testsuite/g++.dg/cpp1z/decomp39.C 2018-04-05 15:10:56.099265281
> +0200
> @@ -0,0 +1,16 @@
> +// PR c++/85209
> +// { dg-do compile { target c++11 } }
> +// { dg-options "" }
> +
> +template <int>
> +void
> +foo ()
> +{
> + auto [a] = []{}; // { dg-error "cannot decompose lambda closure type" }
> +} // { dg-warning "structured bindings only available
> with" "" { target c++14_down } .-1 }
> +
> +void
> +bar ()
> +{
> + foo<0> ();
> +}
> --- gcc/testsuite/g++.dg/cpp1z/decomp40.C.jj 2018-04-05 15:11:58.630265722
> +0200
> +++ gcc/testsuite/g++.dg/cpp1z/decomp40.C 2018-04-05 15:11:49.402265657
> +0200
> @@ -0,0 +1,18 @@
> +// PR c++/85209
> +// { dg-do compile { target c++11 } }
> +// { dg-options "" }
> +
> +struct S { int a; } s;
> +
> +template <int>
> +void
> +foo ()
> +{
> + auto [a] = []{ return s; } (); // { dg-warning "structured bindings
> only available with" "" { target c++14_down } }
> +};
> +
> +void
> +bar ()
> +{
> + foo<0> ();
> +}
>
> Jakub
