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From: "federico.perini at gmail dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug fortran/59202] Erroneous argument aliasing with defined
 assignment
Date: Thu, 03 Jun 2021 08:35:59 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D59202

--- Comment #4 from federico <federico.perini at gmail dot com> ---
The self-assignment issue is present even if the derived type has no
allocatable components. Here is a sample test program that gives an error w=
ith
gfortran 10.2.0:=20

module assign
        implicit none
        private


        type, public :: t
             integer :: a=20=20=20=20=20=20=20=20=20=20=20=20=20=20
             contains
                   procedure :: destroy=3D>t_destroy
                   procedure :: assign=3D>t_assign
                   generic :: assignment(=3D) =3D>assign=20
        end type t

   contains


   elemental subroutine t_destroy(this)
        class(t), intent(inout) :: this
        this%a =3D 0
   end subroutine t_destroy

   subroutine t_assign(this,that)
        class(t), intent(inout) :: this
        class(t), intent(in) :: that

        call this%destroy() ! Clean memory first

        select type (thatPtr=3D>that)
           type is (t)
               this%a =3D thatPtr%a=20=20=20=20
        end select

   end subroutine t_assign
end module assign

program test
        use assign
        type(t), allocatable :: t1(:)

        allocate(t1(10))

        do i=3D1,10
          t1(i)%a =3D i
        end do=20=20

        n =3D 0
        do i=3D1,10
          if (mod(i,2)/=3D0) then=20
              n =3D n + 1
              t1(n) =3D t1(i)
              print *, 'i=3D',i,' t(i)%a=3D',t1(i)%a,' expected t(i)%a=3D',=
i,':
',merge('ERROR!','OK    ',t1(i)%a/=3Di)
          endif
        end do

end program test=