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

O 19-04-28 10:20:58, Hans Dembinski wrote:

On Sat, Apr 27, 2019 at 10:32 PM Mateusz Loskot via Boost wrote:

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

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(initially posted to

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

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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

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

#if !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?

As we discussed on Slack, it may work. I'm just not able, resource-wise, to maintain support for GCC 4.8 or similarly ancient compiler in GIL. Anyone who wishes to use GIL with such the oldies is welcome to submit PR. Alternatively, older Boost versions are available. Best regards, -- Mateusz Loskot, http://mateusz.loskot.net Fingerprint=C081 EA1B 4AFB 7C19 38BA 9C88 928D 7C2A BB2A C1F2