J3/17-203r1
To: J3
From: John Reid
Subject: Coarrays that cannot have cosubscripts
Date: 2017 October 16

Discussion:
-----------

If a coarray is of a derived type, a subobject that is formed by
taking a component is also a coarray but it cannot have cosubscripts.
For example, given the declarations
   Type t
      Real r
   End Type
   Type(t) x[10,*]
x%r is a coarray that cannot have cosubscripts. However, it may be
passed as an actual argument to a procedure where the corresponding
dummy argument is a named coarray that can have cosubscripts.

The intrinsic functions COSHAPE (COARRAY [, KIND]),
IMAGE_INDEX (COARRAY,...), LCOBOUND(COARRAY), UCOBOUND(COARRAY), and
THIS_IMAGE(COARRAY,...) are all defined in terms of the possible
cosubscript values that COARRAY may have. They were not intended to be
called for a coarray that cannot have cosubscripts. Edits are provided
to disallow this.


Edits to 17-007r2:
------------------

[373:34] In 16.9.55 COSHAPE (COARRAY [, KIND]), para 3, at end
of item COARRAY, add "If its <designator> has more than one <part-ref>,
the rightmost <part-ref> shall have nonzero corank.".

[394:13] In 16.9.97 IMAGE_INDEX (COARRAY, SUB)..., para 3, in item
COARRAY, after "any type." add "If its <designator> has more than one
<part-ref>, the rightmost <part-ref> shall have nonzero corank.".

[399:22] In 16.9.110 LCOBOUND (COARRAY [, DIM, KIND]), para 3, at end
of item COARRAY, add "If its <designator> has more than one <part-ref>,
the rightmost <part-ref> shall have nonzero corank.".

[435:27] In 16.9.190 THIS_IMAGE([TEAM]),..., para 3, in item COARRAY,
after "allocated." add "If its <designator> has more than one
<part-ref>, the rightmost <part-ref> shall have nonzero corank.".

[439:2] In 16.9.197 UCOBOUND (COARRAY [, DIM, KIND]), para 3, at end
of item COARRAY, add "If its <designator> has more than one <part-ref>,
the rightmost <part-ref> shall have nonzero corank.".