Re: [histogram][type_traits] strange compile error in boost.histogram for gcc-7.1+ with -std=c++17; possible bug in gcc?

From: Thomas Ferrand (a.tom.hic3_at_[hidden])
Date: 2020-10-30 15:39:43

Le 30/10/2020 à 15:16, Hans Dembinski via Boost a écrit :
>> On 30. Oct 2020, at 14:52, Hans Dembinski <hans.dembinski_at_[hidden]> wrote:
>>
>> Dear John and the other gurus,
>>
>> a strange bug was reported for Boost.Histogram. It is a difficult one for which I would like to ask for help. To me it looks like a bug in gcc.
>>
>> Here is the issue:
>> https://github.com/boostorg/histogram/issues/290
> Here is an absolute minimal example which does not include boost at all.
>
> https://godbolt.org/z/hrcYao
>
> clang is ok, msvc is ok, gcc fails.
>
>
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Not, an expert but I would say it looks like a gcc bug.

As a workaround the function in the nested namespace can be declared 
with a trailing return type, this doesn't seem to trigger the bug: 
https://godbolt.org/z/fY979r

Thomas