On Fri, Jan 5, 2024 at 11:50 AM Patrick Palka <ppa...@redhat.com> wrote:
>
> Bootstrapped and regtested on x86_64-pc-linux-gnu, does this look OK
> for trunk and perhaps 13?
Ping.
>
> -- >8 --
>
> invalid_tparm_referent_p was rejecting using the address of a class NTTP
> object as a template argument, but this should be fine.
>
> PR c++/113242
>
> gcc/cp/ChangeLog:
>
> * pt.cc (invalid_tparm_referent_p) <case ADDR_EXPR>: Suppress
> DECL_ARTIFICIAL rejection test for class NTTP objects.
>
> gcc/testsuite/ChangeLog:
>
> * g++.dg/cpp2a/nontype-class61.C: New test.
> ---
> gcc/cp/pt.cc | 3 ++-
> gcc/testsuite/g++.dg/cpp2a/nontype-class61.C | 27 ++++++++++++++++++++
> 2 files changed, 29 insertions(+), 1 deletion(-)
> create mode 100644 gcc/testsuite/g++.dg/cpp2a/nontype-class61.C
>
> diff --git a/gcc/cp/pt.cc b/gcc/cp/pt.cc
> index 154ac76cb65..8c7d178328d 100644
> --- a/gcc/cp/pt.cc
> +++ b/gcc/cp/pt.cc
> @@ -7219,7 +7219,8 @@ invalid_tparm_referent_p (tree type, tree expr,
> tsubst_flags_t complain)
> * a string literal (5.13.5),
> * the result of a typeid expression (8.2.8), or
> * a predefined __func__ variable (11.4.1). */
> - else if (VAR_P (decl) && DECL_ARTIFICIAL (decl))
> + else if (VAR_P (decl) && !DECL_NTTP_OBJECT_P (decl)
> + && DECL_ARTIFICIAL (decl))
> {
> if (complain & tf_error)
> error ("the address of %qD is not a valid template argument",
> diff --git a/gcc/testsuite/g++.dg/cpp2a/nontype-class61.C
> b/gcc/testsuite/g++.dg/cpp2a/nontype-class61.C
> new file mode 100644
> index 00000000000..90805a05ecf
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/cpp2a/nontype-class61.C
> @@ -0,0 +1,27 @@
> +// PR c++/113242
> +// { dg-do compile { target c++20 } }
> +
> +struct wrapper {
> + int n;
> +};
> +
> +template<const wrapper& X>
> +void f1() {
> + static_assert(X.n == 42);
> +}
> +
> +template<const wrapper* X>
> +void f2() {
> + static_assert(X->n == 42);
> +}
> +
> +template<wrapper X>
> +void g() {
> + f1<X>();
> + f2<&X>();
> +}
> +
> +int main() {
> + constexpr wrapper X = {42};
> + g<X>();
> +}
> --
> 2.43.0.254.ga26002b628
>
