Re: [boost] [MP11] Loosing const-qualification on type result with GCC 4.8 only

Hi Mateusz, Peter, On Sat, Apr 27, 2019 at 10:32 PM Mateusz Loskot via Boost < boost@lists.boost.org> wrote:

On 19-04-26 01:05:12, Mateusz Loskot wrote:

...

(initially posted to

https://lists.boost.org/boost-users/2019/04/89778.php)

...

I prepared a lenghty MWE which reproduces my problem with type manipulation using MP11 that for some reason looses const-qualification on a ::type result

[...]

https://github.com/boostorg/mp11/blob/e5d6e0d0b991a99c71a2b8f5057d0f0a1a89e0...

#if https://github.com/boostorg/mp11/blob/e5d6e0d0b991a99c71a2b8f5057d0f0a1a89e0... !BOOST_MP11_WORKAROUND( BOOST_MP11_GCC, < 40900 ) // g++ 4.7, 4.8 have difficulties with preserving top-level const BOOST_TEST_TRAIT_TRUE((std::is_same, void const>)); BOOST_TEST_TRAIT_TRUE((std::is_same, int const[]>)); #endif

Since GCC 4.8 is dying, it's a good idea to stop using it where MP11 + C++11 is required.

how about wrapping the const type in mp_identity as a workaround before doing transforms, and then unwrapping?