F2k3には仮想デストラクタがないことを正しく理解していますか?
stefanos-imac:oop borini$ cat a.f90
module AModule
   type :: AType
      contains
      final :: A_dtor
   end type
contains
   subroutine A_dtor(self)
      type(AType), intent(inout) :: self
      print *, "A_dtor"
   end subroutine
end
stefanos-imac:oop borini$ cat b.f90 
module BModule
   use AModule
   type,extends(AType) :: BType
      contains
      final :: B_dtor
   end type
contains
   subroutine B_dtor(self)
      type(BType), intent(inout) :: self
      print *, "B_dtor"
   end subroutine
end
stefanos-imac:oop borini$ cat x.f90 
program x
   use AModule
   use BModule
   class (AType), pointer :: baseptr
   type(BType), pointer :: derivedptr
   allocate(derivedptr)
   baseptr => derivedptr
   deallocate(baseptr)
end program
stefanos-imac:oop borini$ ./a.out 
 A_dtor
forrtl: severe (173): A pointer passed to DEALLOCATE points to an array that cannot be deallocated
Image              PC                Routine            Line        Source             
a.out              0000000108A731F4  Unknown               Unknown  Unknown
a.out              0000000108A7198E  Unknown               Unknown  Unknown
a.out              0000000108A4D791  Unknown               Unknown  Unknown
a.out              0000000108A2283E  Unknown               Unknown  Unknown
a.out              0000000108A3B930  Unknown               Unknown  Unknown
a.out              0000000108A1EF10  Unknown               Unknown  Unknown
a.out              0000000108A0A104  Unknown               Unknown  Unknown
a.out              0000000108A09F0C  Unknown               Unknown  Unknown
a.out              0000000108A09EC4  Unknown               Unknown  Unknown