If a dummy argument name is the same as the name of the module containing the interface an ICE (or other errors, according to the test case) results.
-- Summary: ICE on module name vs dummy argument name Product: gcc Version: 4.1.0 Status: UNCONFIRMED Severity: normal Priority: P2 Component: fortran AssignedTo: unassigned at gcc dot gnu dot org ReportedBy: sfilippone at uniroma2 dot it GCC build triplet: i686-pc-linux-gnu GCC host triplet: i686-pc-linux-gnu GCC target triplet: i686-pc-linux-gnu http://gcc.gnu.org/bugzilla/show_bug.cgi?id=24409