[Bug c/43651] add warning for duplicate qualifier

[miyuki at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=43651

Mikhail Maltsev <miyuki at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|---                         |FIXED

--- Comment #9 from Mikhail Maltsev <miyuki at gcc dot gnu.org> ---
Fixed for GCC 7.