J3/14-137
To: J3
Subject: C1293 (constraint on pure subprograms)
From: Van Snyder
Date: 2014 April 01

1. Introduction
===============

C1293 [316:7-19] says

"In a pure subprogram any designator with a base object that is in
 common or accessed by host or use association, is a dummy argument of a
 pure function, is a dummy argument with the INTENT (IN) attribute, is a
 coindexed object, or an object that is storage associated with any such
 variable, shall not be used

 (1) in a variable definition context (16.6.7),
 (2) as the <data-target> in a <pointer-assignment-stmt>,
 (3) as the <expr> corresponding to a component with the POINTER
     attribute in a <structure-constructor>,
 (4) as the <expr> of an intrinsic assignment statement in which the
     variable is of a derived type if the derived type has a pointer
     component at any level of component selection,
 (5) as the <source-expr> in a SOURCE= clause if the designator is of a
     derived type that has an ultimate pointer component, or
 (6) as an actual argument corresponding to a dummy argument with INTENT
     (OUT) or INTENT (INOUT) or with the POINTER attribute.

C1282 requires a dummy argument of a pure function to have the
INTENT(IN) or VALUE attribute.

There is no constraint similar to C1293 concerning local variables of
pure subprograms.  Dummy arguments with the VALUE attribute are
effectively local variables.

Therefore, for a dummy argument of a pure function has the VALUE
attribute, there is no problem that is solved by C1293.

Therefore, it is enough for C1293 to have "is a dummy argument with the
INTENT (IN) attribute".  It doesn't need "is a dummy argument of a pure
function".

2. Edits to 14-007
==================

[316:8] Delete ", is a dummy argument of a pure function"

[316:9] Insert "is" before "an" (for consistency with the rest of the
sentence).

[316:16] Replace "clause" with "specifier".