To: J3                                                     J3/23-170
From: John Reid & Reinhold Bader
Subject: Interp for MOVE_ALLOC
Date: 2023-June-10

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NUMBER: Fxx/xxx
TITLE: MOVE_ALLOC is insufficiently specified
KEYWORDS: MOVE_ALLOC, coarray
DEFECT TYPE: Erratum
STATUS: J3 consideration in progress
REFERENCES: N2213 (FDIS)

INTRODUCTION
It appears that MOVE_ALLOC is insufficiently specified for arguments
that are coarrays or have coarray subobjects. The latter is a consequence
of the fact that the base object is permitted to be allocatable in
Fortran 2023.

QUESTION 1:
If FROM is a coarray, is it required that all images of the team have
corresponding coarrays?

QUESTION 2:
If TO is an allocated coarray, is it required that all images of the
team have corresponding coarrays?

QUESTION 3:
If FROM is of a type with a potential coarray subobject, was it intended
thatMOVE_ALLOC be applicable to it?

ANSWER 1:
Yes, this is required because FROM becomes deallocated (even though
the memory it referred to continues to exist).
An edit is supplied.

ANSWER 2:
Yes, this is required because TO is deallocated in this case.
An edit is supplied.

ANSWER 3 - Alternative 1
No, it was not intended that MOVE_ALLOC be applicable to such objects.
An edit is supplied to prevent such usage.

ANSWER 3 - Alternative 2
Yes, it was intended that MOVE_ALLOC can be applied to such objects.
However, the side effects of extending the coarray facilities to
allocatable objects with coarray subobjects were overlooked.
Edits are supplied to account for this case.

EDITS to N2213:

Question 1

In 16.9.147 MOVE_ALLOC, at the end of the para labelled FROM, add
"If it is a coarray, all images of the current team shall have
corresponding coarrays."

Question 2

In 16.9.147 MOVE_ALLOC, at the end of the para labelled TO, add
"If it is an allocated coarray, all images of the current
team shall have corresponding coarrays."

Question 3, Alternative 1

In 16.9.147 MOVE_ALLOC, in the para labelled FROM, after
"may be of any type, rank, and corank." add
"It shall not be of a type with a potential coarray subobject component".

Question 3, Alternative 2

In 16.9.147 MOVE_ALLOC, at the end of the para labelled FROM, add
"If it is an object with an allocated potential coarray subobject
component, that subobject shall correspond on all images of the
current team."

In 16.9.147 MOVE_ALLOC, at the end of the para labelled TO, add
"If it is an object with an allocated potential coarray subobject
component, that subobject shall correspond on all images of the
current team."

In 16.9.147 MOVE_ALLOC, in the para dealing with the coarray case,
after
"When a reference to MOVE_ALLOC is executed for which the FROM argument
 is a coarray"
add
" or of a type with a potential coarray subobject component".


SUBMITTED BY: John Reid & Reinhold Bader

HISTORY: 23-xxx   m230  Submitted

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