procedure versus module name clash

[Paul Richard Thomas]

Dear All,

I am in the midst of fixing another interface problem - PR20896.  My
patch breaks interface_7.f90 by generating an extra error, which I
think is correct.  interface_7.f90 is:

! { dg-do compile }
! One of the tests of the patch for PR30068.
!  Taken from the fortran 2003 standard C11.2.
!
! The interface is invalid although it is unambiguous because the
! standard explicitly does not require recursion into the formal
! arguments of procedures that themselves are interface arguments.
!
module x
  INTERFACE BAD9
    SUBROUTINE S9A(X)
      REAL :: X
    END SUBROUTINE S9A
    SUBROUTINE S9B(X)
      INTERFACE
        FUNCTION X(A)
          REAL :: X,A
        END FUNCTION X
      END INTERFACE
    END SUBROUTINE S9B
    SUBROUTINE S9C(X)
      INTERFACE
        FUNCTION X(A)
          REAL :: X
          INTEGER :: A
        END FUNCTION X
      END INTERFACE
    END SUBROUTINE S9C  ! { dg-error "Ambiguous interfaces" }
  END INTERFACE BAD9
end module x

! { dg-final { cleanup-modules "x" } }

The patch is picking up the mismatch between module 'x' and function
'x' in the procedure interfaces.  I think this is correct and I
propose to change the name of the module.  However, I have a niggling
doubt about it and would appreciate your opinions.

Paul