On Tue, Dec 17, 2024 at 11:04 AM Patrick Palka <ppa...@redhat.com> wrote:
>
> Bootstrapped and regtested on x86_64-pc-linux-gnu, does this look OK
> for trunk/14/13?
Ping.
>
> -- >8 --
>
> Here during partial substitution of the requires-expression (as part of
> CTAD constraint rewriting) we segfault from the INDIRECT_REF case of
> convert_to_void due *f(u) being type-dependent. We should just defer
> checking convert_to_void until satisfaction.
>
> PR c++/118060
>
> gcc/cp/ChangeLog:
>
> * constraint.cc (tsubst_valid_expression_requirement): Don't
> check convert_to_void during partial substitution.
>
> gcc/testsuite/ChangeLog:
>
> * g++.dg/cpp2a/concepts-requires40.C: New test.
> ---
> gcc/cp/constraint.cc | 4 +++-
> gcc/testsuite/g++.dg/cpp2a/concepts-requires40.C | 12 ++++++++++++
> 2 files changed, 15 insertions(+), 1 deletion(-)
> create mode 100644 gcc/testsuite/g++.dg/cpp2a/concepts-requires40.C
>
> diff --git a/gcc/cp/constraint.cc b/gcc/cp/constraint.cc
> index c75982d8009..eb47862fda0 100644
> --- a/gcc/cp/constraint.cc
> +++ b/gcc/cp/constraint.cc
> @@ -1336,7 +1336,9 @@ tsubst_valid_expression_requirement (tree t, tree args,
> sat_info info)
> {
> tsubst_flags_t quiet = info.complain & ~tf_warning_or_error;
> tree r = tsubst_expr (t, args, quiet, info.in_decl);
> - if (convert_to_void (r, ICV_STATEMENT, quiet) != error_mark_node)
> + if (r != error_mark_node
> + && (processing_template_decl
> + || convert_to_void (r, ICV_STATEMENT, quiet) != error_mark_node))
> return r;
>
> if (info.diagnose_unsatisfaction_p ())
> diff --git a/gcc/testsuite/g++.dg/cpp2a/concepts-requires40.C
> b/gcc/testsuite/g++.dg/cpp2a/concepts-requires40.C
> new file mode 100644
> index 00000000000..918bab410f3
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/cpp2a/concepts-requires40.C
> @@ -0,0 +1,12 @@
> +// PR c++/118060
> +// { dg-do compile { target c++20 } }
> +
> +int* f(int);
> +
> +template<class T>
> +struct A {
> + template<class U> requires requires (U u) { *f(u); }
> + A(T, U);
> +};
> +
> +A a{0, 0};
> --
> 2.48.0.rc0
>
