J3/14-216
To:      J3
From:    Nick Maclaren
Subject: Unallocated coarray components
Date: 2014 August 07

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NUMBER: TBD
TITLE: Unallocated coarray components
KEYWORD: Coarrays, allocation
DEFECT TYPE: Clarification
STATUS: J3 consideration in progress

QUESTION 1:

Is the following program supposed to be conforming?

PROGRAM Main
    TYPE :: Mytype
        INTEGER, ALLOCATABLE :: data(:)
    END TYPE Mytype
    TYPE(Mytype) :: coarray_1[*], coarray_2[*]
    IF (THIS_IMAGE() == 2) THEN
        ALLOCATE(coarray_2%data(3))
        coarray_2%data = 123
    END IF
    SYNC ALL
    IF (THIS_IMAGE() == 1) THEN
        coarray_1 = coarray_2[2]
        PRINT *, coarray_1%data
    END IF
END PROGRAM Main


QUESTION 2:

Is the following program supposed to be conforming?

PROGRAM Main
    TYPE :: Mytype
        INTEGER, ALLOCATABLE :: data(:)
    END TYPE Mytype
    TYPE(Mytype) :: coarray_1[*], coarray_2[*]
    IF (THIS_IMAGE() == 2) THEN
        ALLOCATE(coarray_2%data(3))
        coarray_2%data = 123
    END IF
    SYNC ALL
    IF (THIS_IMAGE() == 1) CALL Fred (coarray_1)
CONTAINS
    SUBROUTINE Fred (arg)
        TYPE(Mytype) :: arg
        arg = coarray_2[2]
        PRINT *, arg%data
    END SUBROUTINE Fred
END PROGRAM Main


DISCUSSION:

7.2.1.2p1(3) says "the variable and expr shall be conformable unless the
variable is an allocatable array that has the same rank as expr and is
neither a coarray nor a coindexed object".

7.2.1.3p13 describes assignment of derived types, essentially to be
recursive.

This seems to forbid the first example but not the second, despite their
near-equivalence, but I don't think that was intended.  It needs
clarifying, in any case.


ANSWER:

Awaiting statement of direction.


EDITS:

Awaiting statement of direction.


SUBMITTED BY: Nick Maclaren


HISTORY: m205   14-nnn   Submitted