[Bug fortran/55352] New: Erroneous gfortran warning of unused module variable when variable is only used in namelist

["AstroFloyd at gmail dot com" <gcc-bugzilla@gcc.gnu.org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55352

             Bug #: 55352
           Summary: Erroneous gfortran warning of unused module variable
                    when variable is only used in namelist
    Classification: Unclassified
           Product: gcc
           Version: 4.7.2
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: fortran
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: AstroFloyd@gmail.com


Created attachment 28709
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=28709
Minimal example source code

gfortran-4.7.2 -Wall gives a warning about unused module variables when those
variables are only used in a namelist.

Test: compile the attached minimal example source file test.f90 with:
gfortran -v -Wall -Werror test.f90 -o test

The following warning is printed:
test.f90:14.6:

  use data, only: a
      1
Warning: Unused module variable 'a' which has been explicitly imported at (1)

The warning goes away when print*,a is uncommented in line 20.  Verbose output
is in the attached file compile_output.txt


Get:     warning about unused module variable
Expect:  no warning
Reproduceable:  always
gfortran version: gcc version 4.7.2 (Gentoo 4.7.2 p1.3, pie-0.5.5)