Assignment with polymorphic component, wrong result

[MR]

Hi,
   the attached code should print "1  2", however, it prints "2  2".
Indeed, it seems that each assignment to V(I) in fact assigns to the
whole array V.

ifort -V
Intel(R) Fortran Intel(R) 64 Compiler XE for applications running on Intel(R) 64, Version 13.1 Build 20130121

(I don't have the very latest version, so I don't know how it works).

program ts
 implicit none
 type, abstract :: at
  integer :: f
 end type at
 type, extends(at) :: t
 end type t
 type :: tv
  class(at), allocatable :: x
 end type tv

 type(tv), allocatable :: v(:)
 type(tv) :: x

  allocate(v(2))
  allocate(t::x%x)
  x%x%f = 1
  v(1) = x
  x%x%f = 2
  v(2) = x
  ! Should print "1  2"
  write(*,*) v(1)%x%f, v(2)%x%f

end program ts

[Steven_L_Intel1]

I can reproduce this with the latest version - thanks. We'll look into it.

[Steven_L_Intel1]

Escalated as issue DPD200243378. It is somewhat interesting that intrinsic assignment to a polymorphic variable is non-standard in F2003 (it is new in F2008) and we don't yet support that, but a polymorphic allocatable component of a derived type is ok in F2003 (and we are supposed to support that feature.)

[MR]

Steve, thank you for the update.

It is somewhat interesting that intrinsic assignment to a polymorphic variable is non-standard in F2003 (it is new in F2008) and we don't yet support that, but a polymorphic allocatable component of a derived type is ok in F2003 (and we are supposed to support that feature.)

Yes, indeed. It looks like this parallels what happened with allocatable arrays: initially they were reallocated only inside derived types (F95+TR), but not as standalone variables, and then this "inconsistency" was removed allowing reallocation of the left-hand-side (F2003).

Marco

[Steven_L_Intel1]

This has been fixed for a future update, probably October.

[m_sulc]

Interestingly, using the (hopefully not so old-fashioned) "Intel(R) Fortran Intel(R) 64 Compiler XE for applications running on Intel(R) 64, Version 12.1.5.339 Build 20120612", the provided example compiles fine, nevertheless the result seems to be "0 0"...

[Steven_L_Intel1]

The problem is not a compile error, it's wrong results at run-time. Version 12.1.5 is about a year old

[m_sulc]

Yes, of course, I just wanted to point out that the older version produces a different result (still incorrect, though). There, the problem seems to mainly consist in the fact that after the assignment:
[fortran]
v(1) = x
[/fortran]
v(1)%x is not allocated, although it (in F2003) should, right?
Using ifort 13, ALLOCATED(v(1)%x) returns .TRUE.

[Steven_L_Intel1]

The present problem is that the compiler incorrectly handles the assignments to v(1) and v(2), effectively assigning to all elements of v for each assignment. The write of v(2) overwrote the value of v(1), leading to the wrong result.

I would not be astonished that 12.1 got it even more wrong.