https://gcc.gnu.org/bugzilla/show_bug.cgi?id=119813
Bug ID: 119813
Summary: std::is_invocable thinks void can be passed to ...
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: libstdc++
Assignee: unassigned at gcc dot gnu.org
Reporter: blubban at gmail dot com
Target Milestone: ---
#include <type_traits>
void a(...);
bool b()
{
return std::is_invocable_v<decltype(a), void>;
}
template<typename T>
bool c()
{
return requires { a(std::declval<T>()); };
}
bool d() { return c<void>(); }
or, somewhat shorter:
#include <type_traits>
static_assert(!std::is_invocable_v<void(*)(...), void>);
Expected: Both b and d should be false. declval<void>() is illegal, so so the
expression INVOKE(declval<Fn>(), declval<ArgTypes>()...) is not well-formed
when treated as an unevaluated operand.
Actual: b is true, d is false.
https://godbolt.org/z/3KK63MYxY
