https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112407
--- Comment #6 from Paul Thomas <pault at gcc dot gnu.org> ---
(In reply to Tomáš Trnka from comment #5)
> I'm looking forward to any more information on the root cause.
I have failed to produce a compact reproducer that resembles your bug. In fact,
you will note the first comment in the reproducer below, which is a bit ironic
:-).
You will note the commented out assignment and select type block. These
generate the exact error. ie. Whenever 'new_t' appears in a variable expression
the error is triggered.
I am deeply puzzled and will have another go at achieving some enlightenment
tomorrow.
Paul
module m
private new_t
type s
procedure(),pointer,nopass :: op
end type
type :: t
integer :: i
type (s) :: s
contains
procedure :: new_t
procedure :: bar
procedure :: add_t
generic :: new => new_t, bar
generic, public :: assignment(=) => add_t
final :: final_t
end type
integer :: i = 0, finals = 0
contains
! recursive subroutine new_t (arg1, arg2) ! gfortran doesn't detect the
recursion
subroutine new_t (arg1, arg2) ! in 'new_t'! Other brands do.
class(t), intent(out) :: arg1
type(t), intent(in) :: arg2
i = i + 1
! arg1%s%op => new_t ! This generates the error
! select type (arg1) ! As does this
! type is (t)
! arg1 = t(arg1%i,s(new_t))
! end select
print *, "new_t"
if (i .ge. 10) return
! arg1 = arg2 ! gfortran does not detect the recursion
if (arg1%i .ne. arg2%i) then ! According to F2018(8.5.10), arg1 should be
arg1%i = arg2%i ! undefined on invocation, unless any
sub-components
call arg1%new(arg2) ! are default initialised. gfortran sets
arg1%i = 0
endif ! gfortran misses this recursion
end
subroutine bar(arg)
class(t), intent(out) :: arg
call arg%new(t(42, s(new_t)))
end
subroutine add_t (arg1, arg2)
class(t), intent(out) :: arg1
type(t), intent(in) :: arg2
call arg1%new (arg2)
end
impure elemental subroutine final_t (arg1)
type(t), intent(in) :: arg1
finals = finals + 1
end
end
use m
class(t), allocatable :: x
allocate(x)
call x%new() ! gfortran ouputs 10*'new_t'
print *, x%i, i, finals ! -||- 0 10 11
!
! The other brands output 2*'new_t' + 42 2 3
end
