keeping array limits in fortran during subroutine call

I have the following program

module test
contains
   subroutine foo()
      integer, allocatable :: a(:)
      allocate(a(-5:5))
      call bar(a)
      print *, a
   end subroutine
   subroutine bar(a)
      integer, intent(out) :: a(:)
      a = 0 
      a(-4) = 3  ! here
      a(2) = 3   
   end subroutine
end module

program x
   use test
   call foo()
end program

In the line marked with "here" I am doing something wrong. The fact is that when I receive the array a (in the caller allocated from -5 to +5), the callee uses conventional numbering (1 to n), meaning that assigning -4 I am doing an out of boundary assignment. How can I instruct the compiler that, within the bar routine, the numbering of the a array must be the same as in the caller ?