J3/17-231r1
To: J3
From: Malcolm Cohen
Subject: USE statement mis-statements
Date: 2017 October 16


1. Introduction

14.2.2 "The USE statement and use association" correctly describes, in
paragraph 2, the association model: that there are local entities (with
their own identifiers, usually the same identifiers as the module
entities) that are associated with the module entities.

However, paragraph 7 describes a different model, where the module
entities have local identifiers.  This is confusing.

Also, the description in this subclause states that the associated
entities/identifiers are "local" entities/identifiers, which contradicts
the wording for the use of USE in a BLOCK construct, where they are
construct entities.  This is especially gratuitous in paragraph two,
where the entities are first called "accessed entities" and subsequently
referred to using the different term "local entities".

Finally, uniqueness of use association excludes "generic interfaces and
defined operators", but a defined operator is merely an identifier for a
generic interface.  This is both redundant and incorrect - the entity
being accessed is the generic interface, and when p8 says that "Generic
interfaces and defined operators are handled as described in 15.4.3.4",
it is notable that 15.4.3.4 makes no mention of operators whatsoever.

Finally, in 19.4 Statement and construct entities, it is not immediately
obvious that a USE statement has explicitly declared its accessed
entities.

Edits are provided to address these flaws.


2. Edits to 17-007r2

[296:27,30,31] 14.2.2 The USE statement and use association, p2.
    "except that a local entity" -> "except that an accessed entity",
    "default, the local entities" -> "default, the accessed entities",
    "different local" -> "different".
{Remove unnecessarily different, and incorrect, terminology/}
This makes that whole enormous paragraph read:
   "The USE statement provides the means by which a scoping unit accesses
    named data objects, derived types, procedures, abstract interfaces,
    generic identifiers, and namelist groups in a module. The entities in
    the scoping unit are use associated with the entities in the module.
    The accessed entities have the attributes specified in the module,
    except that an accessed entity may have a different accessibility
    attribute, it may have the ASYNCHRONOUS attribute even if the
    associated module entity does not, and if it is not a coarray it may
    have the VOLATILE attribute even if the associated module entity does
    not. The entities made accessible are identified by the names or
    generic identifiers used to identify them in the module. By default,
    the accessed entities are identified by the same identifiers in the
    scoping unit containing the USE statement, but it is possible to
    specify that different identifiers are used. A use-associated entity
    is considered to have been previously defined."

[298:3] Same subclause, p7,
    After "An accessible entity in the referenced module"
    change "has one or more local identifiers."
    to     "is associated with one or more accessed entities, each with
            its own identifier.".
{State the model we use correctly.}
Note: this sentence is followed by "These identifiers are" and a list of
      how the identifiers are determined.

[298:10-14] Replace entirety of paragraph 8 with:
   "An ultimate entity is a module entity that is not accessed by use
    association. An accessed entity shall not be associated with two or
    more ultimate entities unless its identifier is not used, or the
    ultimate entities are generic interfaces. Generic interfaces are
    handled as described in 15.4.3.4."
{Rewrite to be a simple direct requirement.
 The first sentence is actually unchanged.}

[516:13] 19.4 Statement and construct entities, p1,
    Before "Two construct entities" insert a new sentence
    "A USE statement in a BLOCK construct explicitly declares the
     entities accessed by use association to be construct entities."
{Make it very clear that USE works as one would expect.}

===END===