J3/04-336r1

Date:    10 June 2004
To:      J3
From:    Rob James
Subject: Allocating objects of abstract types

NUMBER:
TITLE: Allocating objects of abstract types
KEYWORDS: ALLOCATE, ABSTRACT
DEFECT TYPE:
STATUS: J3 consideration in progress

QUESTION:
Consider the following code:

      module m
        type, abstract :: t
          integer :: i
        end type
        class(t), allocatable :: d
      end module

      program foo
        use m
        allocate(d)
      end

One cannot declare a non-polymorphic object of an abstract type.
Similarly, a polymorphic object should not be allocated with a dynamic
type that is abstract.

A <type-spec> in an allocate statement cannot specify an abstract
type.  But the effect of the allocate statement in the example above
is the same as if a <type-spec> specifying an abstract type appeared
in the allocate statement, which would not be standard-conforming.

Was this example intended to be standard-conforming?

ANSWER:
No, this example was not intended to be standard-conforming.  An edit
is provided to correct this oversight.

EDITS:
This edit refers to 04-007.
[111:12+] Add the following constraint:
  C625.1 (R623) If any <allocate-object> has a declared type that is
         abstract, either <type-spec> or SOURCE= shall apear.

SUBMITTED BY: Rob James

HISTORY: 04-336   m169 Submitted