[Patch, fortran] PR20880 - Failure to detect procedures encompassing own interface

[Grigory Zagorodnev]

 > 2006-11-23 Paul Thomas  <pault@gcc.gnu.org>
 >    PR fortran/20880

Hi!
This patch causes compile-time regression on SPEC cpu2006/481.wrf at 
{x86_64|i686|ia64}-redhat-linux. The patch detects ambiguity when two 
different modules contains same function name. Minimal reproducer is below.

My Fortran Standard knowledge is superficial to provide an opinion, but 
Intel Fortran compiler passes this code through.

Is this new behavior correct or not?

Thanks.
- Grigory

$ cat module_mp_ncloud3.f90
MODULE module_mp_ncloud3
CONTAINS
       real function fpvs()
       fpvs=1.0
       END FUNCTION fpvs
END MODULE module_mp_ncloud3

$ cat module_mp_ncloud5.f90
MODULE module_mp_ncloud5
CONTAINS
       real function fpvs()
       fpvs=1.0
       END FUNCTION fpvs
END MODULE module_mp_ncloud5

$ cat module_physics_init.f90
MODULE module_physics_init
    USE module_mp_ncloud3
    USE module_mp_ncloud5
END MODULE module_physics_init

$ gfortran -c *.f90
module_physics_init.f90:2.24:

    USE module_mp_ncloud3
                        1
Error: Procedure fpvs at (1) is ambiguous