https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82992
--- Comment #4 from Harald Anlauf <anlauf at gmx dot de> --- The accepts-invalid also happens for the simpler examples: subroutine sub (c_int) use iso_c_binding, only: c_int end The NAG compiler complains: NAG Fortran Compiler Release 6.1(Tozai) Build 6106 Error: pr82992b.f90, line 2: Name clash between dummy argument C_INT and symbol from USE ISO_C_BINDING detected at C_INT@<end-of-statement> Warning: pr82992b.f90, line 3: Unused dummy variable C_INT [NAG Fortran Compiler pass 1 error termination, 1 error, 1 warning] or for a simple, non-intrinsic module: module pr82992 integer :: x end module pr82992 subroutine sub (x) use pr82992 end Error: pr82992c.f90, line 5: Name clash between dummy argument X and symbol from USE PR82992 detected at PR82992@<end-of-statement> Warning: pr82992c.f90, line 6: Unused dummy variable X [NAG Fortran Compiler pass 1 error termination, 1 error, 1 warning]