https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88735
Bug ID: 88735
Summary: Nested assignment triggers call of final method for
right hand side
Product: gcc
Version: 8.2.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: fortran
Assignee: unassigned at gcc dot gnu.org
Reporter: mscfd at gmx dot net
Target Milestone: ---
In the following code a type "t" is defined in module mod, which provides an
assignment method and a final routine. The program itself defines a type "s",
with a component of type "t". Assignment "b=a" should call the final method for
b%x, as procedure "set" has intent(out) for self. However, as can be seen from
the output, finalise is called for the right hand side (the intent(in)
argument). The set routine is called afterwards, surprisingly still thinks that
x%i is allocated (it has been wrongly deallocated within finalise). The value
however is somehow set to zero (looks like the deallocated memory zeroed?).
The problem does not occur with intent(inout) for argument "self" in procedure
"set", as finalise is not called at all. The problem does not occur if a and b
are of type t. The nested assignment via type s is necessary to trigger the
bug.
module mod
implicit none
private
type, public :: t
integer, pointer :: i => null()
contains
procedure, public :: set
generic, public :: assignment(=) => set
final :: finalise
end type t
contains
subroutine set(self, x)
class(t), intent(out) :: self
class(t), intent(in) :: x
if (associated(x%i)) then
print *, 'setting: ', x%i
self%i => x%i
self%i = self%i + 1
end if
end subroutine set
subroutine finalise(self)
type(t), intent(inout) :: self
if (associated(self%i)) then
print *, 'finalising: ', self%i
deallocate(self%i)
end if
end subroutine finalise
end module mod
program finalise_assign
use mod
implicit none
type :: s
type(t) :: x
end type s
type(s) :: a, b
allocate(a%x%i)
a%x%i = 123
b = a
end program finalise_assign
