Catch assignment to INTENT(IN) dummy arguments

[ppenzin]

Fort does not catch assignment to dummy arguments marked INTENT(IN):

$ cat intent.f95 
subroutine s(x)
  integer, intent(in) :: x
  x = x + 1
end subroutine
program p
  call s(1)
end program
$ fort -fsyntax-only intent.f95
$ gfortran -fsyntax-only intent.f95
intent.f95:3:2:

   x = x + 1
  1
Error: Dummy argument 'x' with INTENT(IN) in variable definition context (assignment) at (1)