Re: [boost] [optional] Regression in develop

On Mon, Oct 30, 2017 at 12:47 AM, Andrzej Krzemienski via Boost wrote:

The following is a test case in type_traits by Vinnie Falco: https://github.com/boostorg/type_traits/pull/52/commits/9779157a787620d16330...

My idea for a fix is to just specialize `type_traits::is_default_constructible` for `std::pair` where U is a built-in type, by returning `is_default_constructible<T>`. This solves the problem for Optional, which invokes `is_default_constructible` with `std::pair` in this specific case. Disclosure: Peter Dimov doesn't like it.