https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96204
--- Comment #3 from Jonathan Wakely <redi at gcc dot gnu.org> ---
Reduced:
template<typename...> using void_t = void;
template<typename T> T&& declval();
template <typename, typename = void>
struct has_set_attr_method {
static constexpr bool value = false;
};
template <typename T>
struct has_set_attr_method<T, void_t<decltype(declval<T>().setAttr(1))>> {
static constexpr bool value = true;
};
struct Parent
{
public:
template<typename T>
static bool create() {
return has_set_attr_method<T>::value;
}
};
struct Child : public Parent {
public:
friend class Parent;
private:
void setAttr(int) {
}
};
int main() {
Parent::create<Child>();
}
