[Bug c++/96311] false positive for -Wunused-but-set-variable (const/constexpr identifier used in generic lambda)

[marxin at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96311

Martin Liška <marxin at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
     Ever confirmed|0                           |1
                 CC|                            |marxin at gcc dot gnu.org
   Last reconfirmed|                            |2020-07-27
             Status|UNCONFIRMED                 |WAITING

--- Comment #1 from Martin Liška <marxin at gcc dot gnu.org> ---
Confirmed, but it seems the code is rejected with clang:

pr96311.c:6:10: error: variable 'used' cannot be implicitly captured in a
lambda with no capture-default specified
                return used;
                       ^
pr96311.c:3:16: note: 'used' declared here
        constexpr int used = 0;
                      ^
pr96311.c:4:2: note: lambda expression begins here
        [](auto unused)
        ^
pr96311.c:4:2: warning: expression result unused [-Wunused-value]
        [](auto unused)
        ^~~~~~~~~~~~~~~
2 warnings and 1 error generated.

Is it a valid test-case?