On Fri, Mar 8, 2024 at 9:22 AM Patrick Palka <ppa...@redhat.com> wrote:
>
> On Wed, 28 Feb 2024, Ken Matsui wrote:
>
> > This patch optimizes the compilation performance of
> > std::is_nothrow_invocable by dispatching to the new
> > __is_nothrow_invocable built-in trait.
> >
> > libstdc++-v3/ChangeLog:
> >
> > * include/std/type_traits (is_nothrow_invocable): Use
> > __is_nothrow_invocable built-in trait.
> > * testsuite/20_util/is_nothrow_invocable/incomplete_args_neg.cc:
> > Handle the new error from __is_nothrow_invocable.
> > * testsuite/20_util/is_nothrow_invocable/incomplete_neg.cc:
> > Likewise.
> >
> > Signed-off-by: Ken Matsui <kmat...@gcc.gnu.org>
> > ---
> > libstdc++-v3/include/std/type_traits | 4 ++++
> > .../20_util/is_nothrow_invocable/incomplete_args_neg.cc | 1 +
> > .../testsuite/20_util/is_nothrow_invocable/incomplete_neg.cc | 1 +
> > 3 files changed, 6 insertions(+)
> >
> > diff --git a/libstdc++-v3/include/std/type_traits
> > b/libstdc++-v3/include/std/type_traits
> > index 9af233bcc75..093d85a51a8 100644
> > --- a/libstdc++-v3/include/std/type_traits
> > +++ b/libstdc++-v3/include/std/type_traits
> > @@ -3265,8 +3265,12 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > /// std::is_nothrow_invocable
> > template<typename _Fn, typename... _ArgTypes>
> > struct is_nothrow_invocable
> > +#if _GLIBCXX_USE_BUILTIN_TRAIT(__is_nothrow_invocable)
> > + : public __bool_constant<__is_nothrow_invocable(_Fn, _ArgTypes...)>
> > +#else
> > : __and_<__is_invocable_impl<__invoke_result<_Fn, _ArgTypes...>, void>,
> > __call_is_nothrow_<_Fn, _ArgTypes...>>::type
> > +#endif
> > {
> >
> > static_assert(std::__is_complete_or_unbounded(__type_identity<_Fn>{}),
> > "_Fn must be a complete class or an unbounded array");
> > diff --git
> > a/libstdc++-v3/testsuite/20_util/is_nothrow_invocable/incomplete_args_neg.cc
> >
> > b/libstdc++-v3/testsuite/20_util/is_nothrow_invocable/incomplete_args_neg.cc
> > index 3c225883eaf..3f8542dd366 100644
> > ---
> > a/libstdc++-v3/testsuite/20_util/is_nothrow_invocable/incomplete_args_neg.cc
> > +++
> > b/libstdc++-v3/testsuite/20_util/is_nothrow_invocable/incomplete_args_neg.cc
> > @@ -18,6 +18,7 @@
> > // <http://www.gnu.org/licenses/>.
> >
> > // { dg-error "must be a complete class" "" { target *-*-* } 0 }
> > +// { dg-prune-output "invalid use of incomplete type" }
>
> Is the error coming somewhere from the new build_invoke function? That'd
> be surprising since we pass tf_none to it, which should suppress such
> errors. (You can probably break on cxx_incomplete_type_diagnostic to
> find out where it's coming from.)
Hi Patrick,
Thank you for your review!
This error comes from cxx_incomplete_type_diagnostic in
check_trait_type, i.e., before the new build_invoke function. As we
discussed previously, it would be better if we could produce
diagnostics that are in harmony with libstdc++.
>
> >
> > #include <type_traits>
> >
> > diff --git
> > a/libstdc++-v3/testsuite/20_util/is_nothrow_invocable/incomplete_neg.cc
> > b/libstdc++-v3/testsuite/20_util/is_nothrow_invocable/incomplete_neg.cc
> > index 5a728bfa03b..d3bdf08448b 100644
> > --- a/libstdc++-v3/testsuite/20_util/is_nothrow_invocable/incomplete_neg.cc
> > +++ b/libstdc++-v3/testsuite/20_util/is_nothrow_invocable/incomplete_neg.cc
> > @@ -18,6 +18,7 @@
> > // <http://www.gnu.org/licenses/>.
> >
> > // { dg-error "must be a complete class" "" { target *-*-* } 0 }
> > +// { dg-prune-output "invalid use of incomplete type" }
> >
> > #include <type_traits>
> >
> > --
> > 2.44.0
> >
> >
>
