Finalisation of Abstract Type

So I have an abstract type with allocatable length strings

type, abstract:: firstType
   character(len=:), allocatable:: one, two
  contains
end type

I want to be able to include a final  subroutine:

type, abstract:: firstType
    character(len=:), allocatable:: one

  contains
    final:: destroyFirst
end type

contains

subroutine destroyFirst(typeIn)
end subroutine

Is it possible?   When I try to use type(firstType) then I get 

 error #8313: The TYPE(derived-type-spec) shall not specify an abstract type.

but when I try to use class(firstType) I get the error

error #8339: The dummy argument of a final subroutine must be a variable of the derived type being defined and cannot be optional, pointer, allocatable, or polymorphic.

Is it possible to finalise an abstract type?