[Bug fortran/106576] New: Finalization of temporaries from functions not occuring

["tkoenig at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106576

            Bug ID: 106576
           Summary: Finalization of temporaries from functions not
                    occuring
           Product: gcc
           Version: 13.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: fortran
          Assignee: unassigned at gcc dot gnu.org
          Reporter: tkoenig at gcc dot gnu.org
  Target Milestone: ---

Test case:

$ cat g2.f90
module y
  implicit none
  type foo
     integer :: n
   contains
     final :: cleanup
  end type foo
  interface assignment (=)
     module procedure assign
  end interface assignment (=)
contains

  subroutine assign (rop, op)
    type(foo), intent(inout) :: rop
    type(foo), intent(in) :: op
    rop%n = op%n + 1
    print '(A12,I3)',"assign", rop%n
  end subroutine assign

  function to_foo(n) result(res)
    integer, intent(in) :: n
    type (foo) :: res
    res%n = n
    print '(A12,I3)', "to_foo", res%n
  end function to_foo

  subroutine cleanup (self)
    type (foo), intent(inout) :: self
    print '(A12,I3)', "cleanup", self%n
  end subroutine cleanup
end module y

program memain
  use y
  implicit none
  call chk
contains
  subroutine chk
    type (foo) :: a
    a = to_foo(3)
  end subroutine chk
end program memain
$ gfortran g2.f90 && ./a.out
      to_foo  3
      assign  4
     cleanup  4
$ nagfor g2.f90 && ./a.out
NAG Fortran Compiler Release 7.1(Hanzomon) Build 7101
[NAG Fortran Compiler normal termination]
      to_foo  3
      assign  4
     cleanup  3
     cleanup  4

NAG is in fact correct, the temporary from the function results should also
be finalized.

This actually blocks my little FMPFR library, so I might have a stab
at this myself.