[Bug c++/95872] New: Duplicated warning message in "-Wlogical-op"

[haoxintu at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95872

            Bug ID: 95872
           Summary: Duplicated warning message in "-Wlogical-op"
           Product: gcc
           Version: 11.0
            Status: UNCONFIRMED
          Keywords: diagnostic
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: haoxintu at gmail dot com
                CC: mpolacek at gcc dot gnu.org
  Target Milestone: ---

This code, bug.cc, GCC emits two duplicated warning messages about it.

$cat bug.cc
int a = 10;
decltype(( a or a ) ? 1:0) var = 0;


$g++ -c -Wlogical-op bug.cc
bug.cc:2:14: warning: logical 'or' of equal expressions [-Wlogical-op]

    2 | decltype(( a or a ) ? 1:0) var = 0;

      |            ~~^~~~

bug.cc:2:14: warning: logical 'or' of equal expressions [-Wlogical-op]

All GCC-6 to GCC-trunk versions have this issue.