Add -fimplicit-none-type-always to treat each specification-part
like it has IMPLICIT NONE. This is helpful for enforcing good Fortran
programming practices. We might consider something similar for
IMPLICIT NONE(EXTERNAL) as well.
Add -fimplicit-none-type-never to ignore occurrences of IMPLICIT NONE
and IMPLICIT NONE(TYPE). This is to handle cases like the one below,
which violates the standard but it accepted by some compilers:
subroutine s(a, n) implicit none real :: a(n) integer :: n end