To: J3                                                     J3/21-137
From: John Reid
Subject: Interpretation of CO_REDUCE
Date: 2021-April-19

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NUMBER: F18/xxx
TITLE: Type of main argument of CO_REDUCE
KEYWORDS: CO_REDUCE
DEFECT TYPE: Erratum
STATUS: J3 consideraton in progress

QUESTION:

The arguments of OPERATION are required to be scalar data objects that
are nonallocatable, nonpointer, and nonpolymorphic. Was it intended to
allow the type to have components that are allocatable, pointer, or
polymorphic?

ANSWER:

No. The restrictions were imposed to allow an implementation to
involve an image copying a scalar value to another image as for
intrinsic assignment to a scalar coarray. This would not be possible
if the type were to have an ultimate component that is allocatable,
a pointer, or polymorphic. It was intended for this to be forbidden.
An edit is provided to correct this oversight. Forbidding allocatable
and pointer ultimate components is sufficient to forbid  polymorphic
ultimate components too.

EDIT to 18-007r1:

[356:42] In 16.9.49 CO_REDUCE, para 3, after first sentence, add
    "It shall not be of a type with an ultimate component that is
    allocatable or a pointer".

SUBMITTED BY: John Reid

HISTORY: 21-nnn   m224  Submitted

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