To: J3                                                     J3/23-218
From: John Reid & Reinhold Bader
Subject: Interp on deallocating coarrays that do not correspond
Date: 2023-October-02

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NUMBER: Fxx/xxx
TITLE: Dellocating coarrays that do not correspond
KEYWORDS: Deallocate, coarray
DEFECT TYPE: Erratum
STATUS: J3 consideration in progress
REFERENCES: 23-007r1

QUESTION:
Was it intended to allow the deallocation of coarrays that are allocated
on all images but do not correspond?

For example, in the following program the subroutine is executed on all
images and the coarray s%c is allocated on all images. Does this allow
the deallocate statement to execute successfully and deallocate
subobjects of the actual argument a on some images and subobjects of the
actual argument b on the other images?

program trouble
  type outer
     real, allocatable :: c[:]
  end type outer
  type(outer) :: a, b
  integer :: me,ne
  me = this_image()
  ne = num_images()
  allocate(a%c[*],b%c[*])
  if (me>ne/2) then
     call sub (b)
  else
     call sub (a)
  end if
contains
  subroutine sub(s)
     type(outer),intent(inout) :: s
     write(*,*) "allocated(s%c)=", allocated(s%c)
     deallocate(s%c)
  end subroutine
end program

ANSWER:
Not. It was intended that deallocation should always apply to corresponding
coarrays.

An edit is supplied.

EDIT to 23-007r1:

[148:3] In 9.7.3.2 Deallocation of allocatable variables, last sentence
of para 10 change "it is" to "the corresponding coarrays are" so that the
sentence reads
"A coarray shall not become deallocated on an image unless the
corresponding coarrays are successfully deallocated on all active images
in this team."

SUBMITTED BY: John Reid & Reinhold Bader

HISTORY: 23-169   m230  Submitted