[Bug fortran/65079] New: -Werror= does not work on implicit-procedure warning

[nathanael.huebbe at informatik dot uni-hamburg.de]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65079

            Bug ID: 65079
           Summary: -Werror= does not work on implicit-procedure warning
           Product: gcc
           Version: 4.8.2
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: fortran
          Assignee: unassigned at gcc dot gnu.org
          Reporter: nathanael.huebbe at informatik dot uni-hamburg.de

System: Ubuntu
Affected gfortran versions: at least 4.7.2 and 4.8.2

Description:
Compiling this fortran code

    module bar
        implicit none
    contains
        subroutine baz()
            call bim()
        end subroutine
    end module

    program foo
        use bar

        call baz()
    end program

with the call

    $ gfortran -c -Wimplicit-procedure -Werror=implicit-procedure foo.f90

correctly produces the warning, but fails to turn it into an error.

The behavior is the same if `-Wimplicit-procedure` is absent, and if
`implicit-procedure` is replaced by `-Wimplicit-interface`.