To: J3                                                     J3/20-162
From: Reuben D. Budiardja & Daniel Chen
Subject: UTI 001
Date: 2020-October-13
Reference: 19-250r1, 20-007

Background
-----------
This paper addresses Unresolved Technical Issues (UTI) 001 raised by
the editor as a result of processing 19-250r1 "US 12, Arrays of
coarrays".


Discussions
------------
Two issues were raised in the UTI, the meaning of "same set" and "same
element" [138:7] and [138:6], respectively. This paper addresses these
and provides edits.

UTI 001 on page 138 of 20-007:
"What do you mean "same set", and why does it matter?"

Answer:
When coarray is an ultimate component of a polymorphic variable, every
active image needs to have the same coarray components regardless of
the actual dynamic type of the variable.

UTI 001 on page 138 of 20-007: "For that matter, what is the "same
element"? ... It is also unclear just what problem this restriction is
meant to solve."

Answer:
When a coarray is an ultimate component of an array element, the
parent array is not required to have the same bounds but the
corresponding coarrays need to be allocated when allocation occurs on
all images of the current team.  For instance, if on Image 1, the
parent array is arr(1:10) and on Image 2 the parent array is
arr(3:12), the allocation of the coarray component of arry(1) on Image
1 must correspond to arr(3) on Image 2.


Edits to 20-007
---------------

[138:5-6] In 9.7.1.2 Execution of an ALLOCATE statement, change "it
shall be the same element on those images" to "the element shall have
the same position in array element order on those images."

[138:6-7] In 9.7.1.2 Execution of an ALLOCATE statement, change "the
variable shall have the same set of coarray components" to "the
variable's dynamic type shall have the same coarray components on
those images."

[138:7+] Remove UTI 001.