[Bug libstdc++/69717] std::pair is incompatible with std::is_constructible

[daniel.kruegler at googlemail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69717

--- Comment #2 from Daniel Krügler <daniel.kruegler at googlemail dot com> ---
This is fixed in the current trunk (Tested on gcc HEAD 6.0.0 20160207
(experimental)). Btw.: Your test case is confusing. A better test case would be
the following one, where the static assertion tests the expected outcome:

#include <type_traits>
#include <utility>

struct S {
        S(int) {}
};

int main() {
        using pair_t = std::pair<S, S>;
        static_assert(!std::is_default_constructible<pair_t>::value, "");
}