program dafuq
  implicit none
  integer :: a=1
  integer, parameter :: b=2

  call foo(a,b)
  end program dafuq

  subroutine foo(a,b)
  implicit none
  integer, intent(inout) :: a, b

  a=b  !OK
  b=a  !causes segfault

  end subroutine foo

program dafuq_array
  implicit none
  integer :: a(2)=(/1,1/)
  integer, parameter :: b(2)=(/2,2/)

  call foo(a,b)
  end program dafuq_array

  subroutine foo(a,b)
  implicit none
  integer, intent(inout) :: a(2), b(2)

  a=b  !OK
  b=a  !might cause segfault

  end subroutine foo