https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91630
Bug ID: 91630
Summary: std::any SFINAE breaks valid code since 9.1
Product: gcc
Version: 9.1.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: libstdc++
Assignee: unassigned at gcc dot gnu.org
Reporter: alabuzhev at hotmail dot com
Target Milestone: ---
The following code compiles fine with 8.3, but not with 9.1 or later:
#include <any>
template<typename T>
class wrapper
{
public:
wrapper() = default;
// Change to 0 to make it work
#if 1
wrapper(const T& t)
{
// To make sure it's not instantiated
static_assert(!sizeof(t));
value = t;
}
#endif
wrapper(const wrapper& w)
{
// To make sure it's not instantiated
static_assert(!sizeof(w));
value = w.value;
}
auto& operator=(const T& t)
{
// To make sure it's not instantiated
static_assert(!sizeof(t));
value = t;
return *this;
}
auto& operator=(const wrapper& w)
{
value = w.value;
return *this;
}
private:
T value;
};
int main()
{
wrapper<std::any> a, b;
a = b;
}
See compiler explorer demo:
https://godbolt.org/z/q3o0TX
