To: J3                                                     J3/21-119r1
From: Reuben D. Budiardja & Daniel Chen & Jon Steidel
Subject: UTI 001
Date: 2021-February-28
Reference: 19-250r1, 21-007

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" [138:37] and [138:36], respectively. This paper addresses
these and provides edits.

UTI 001 on page 138 of 21-007:
"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 component regardless of the
actual dynamic type of the variable.

UTI 001 on page 139 of 21-007:
"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 arr(1) on Image 1 must correspond to arr(3) on
Image 2.


Edits to 21-007
---------------
[138:35-36] 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."

After the edit, the sentence reads as:
"If the coarray is an ultimate component of an array element, the element
shall have the same position in array element order on those images."

[138:36-37] In 9.7.1.2 Execution of an ALLOCATE statement, change "the
variable shall have the same set of coarray components" to "the dynamic
type of the variable on those images shall have the coarray component."

After the edit, the sentence reads as:
"If the coarray is an ultimate component of a polymorphic variable,
the dynamic type of the variable on those images shall have the coarray
component."

[138:37+] Remove UTI 001.