c++: mark_single_function and SFINAE [PR108282]
Commit Message
We typically ignore mark_used failure when in a non-SFINAE context for
sake of better error recovery. But in mark_single_function we're
instead ignoring mark_used failure in a SFINAE context, which ends up
causing the second static_assert here to incorrectly fail.
Bootstrapped and regtested on x86_64-pc-linux-gnu, does this look OK for
trunk/12?
PR c++/108282
gcc/cp/ChangeLog:
* decl2.cc (mark_single_function): Ignore mark_used failure
only in a non-SFINAE context rather than in a SFINAE one.
gcc/testsuite/ChangeLog:
* g++.dg/cpp2a/concepts-requires34.C: New test.
---
gcc/cp/decl2.cc | 2 +-
.../g++.dg/cpp2a/concepts-requires34.C | 19 +++++++++++++++++++
2 files changed, 20 insertions(+), 1 deletion(-)
create mode 100644 gcc/testsuite/g++.dg/cpp2a/concepts-requires34.C
Comments
On 1/4/23 11:37, Patrick Palka wrote:
> We typically ignore mark_used failure when in a non-SFINAE context for
> sake of better error recovery. But in mark_single_function we're
> instead ignoring mark_used failure in a SFINAE context, which ends up
> causing the second static_assert here to incorrectly fail.
>
> Bootstrapped and regtested on x86_64-pc-linux-gnu, does this look OK for
> trunk/12?
OK.
> PR c++/108282
>
> gcc/cp/ChangeLog:
>
> * decl2.cc (mark_single_function): Ignore mark_used failure
> only in a non-SFINAE context rather than in a SFINAE one.
>
> gcc/testsuite/ChangeLog:
>
> * g++.dg/cpp2a/concepts-requires34.C: New test.
> ---
> gcc/cp/decl2.cc | 2 +-
> .../g++.dg/cpp2a/concepts-requires34.C | 19 +++++++++++++++++++
> 2 files changed, 20 insertions(+), 1 deletion(-)
> create mode 100644 gcc/testsuite/g++.dg/cpp2a/concepts-requires34.C
>
> diff --git a/gcc/cp/decl2.cc b/gcc/cp/decl2.cc
> index f95529a5c9a..00ed64d1691 100644
> --- a/gcc/cp/decl2.cc
> +++ b/gcc/cp/decl2.cc
> @@ -5600,7 +5600,7 @@ mark_single_function (tree expr, tsubst_flags_t complain)
>
> if (is_overloaded_fn (expr) == 1
> && !mark_used (expr, complain)
> - && (complain & tf_error))
> + && !(complain & tf_error))
> return false;
> return true;
> }
> diff --git a/gcc/testsuite/g++.dg/cpp2a/concepts-requires34.C b/gcc/testsuite/g++.dg/cpp2a/concepts-requires34.C
> new file mode 100644
> index 00000000000..670a6dab31a
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/cpp2a/concepts-requires34.C
> @@ -0,0 +1,19 @@
> +// PR c++/108282
> +// { dg-do compile { target c++20 } }
> +
> +template<class T>
> +concept TEST = requires { T::TT; };
> +
> +struct C { };
> +
> +template<class AT>
> +struct B {
> + static inline void TT() requires TEST<AT>;
> +};
> +
> +int main() {
> + static_assert( !TEST<C> );
> + static_assert( !TEST<B<C>> );
> +
> + B<C>::TT(); // { dg-error "no match" }
> +}
@@ -5600,7 +5600,7 @@ mark_single_function (tree expr, tsubst_flags_t complain)
if (is_overloaded_fn (expr) == 1
&& !mark_used (expr, complain)
- && (complain & tf_error))
+ && !(complain & tf_error))
return false;
return true;
}
new file mode 100644
@@ -0,0 +1,19 @@
+// PR c++/108282
+// { dg-do compile { target c++20 } }
+
+template<class T>
+concept TEST = requires { T::TT; };
+
+struct C { };
+
+template<class AT>
+struct B {
+ static inline void TT() requires TEST<AT>;
+};
+
+int main() {
+ static_assert( !TEST<C> );
+ static_assert( !TEST<B<C>> );
+
+ B<C>::TT(); // { dg-error "no match" }
+}