To: J3                                                     10-213
From: R. Bader
Subject: public generic with same name as private type
Date: 2010 September 27
Reference: N1814

NUMBER: F08/xxxx
TITLE: public generic with same name as private type
KEYWORDS: generic, accessibility
DEFECT TYPE: Request for interpretation
STATUS: J3 consideration in progress


Consider the following code:

module m
  implicit none
  private
  public :: foo
  type, private :: foo
    integer :: i = 0
  end type
  type(foo), public :: o_foo
  interface foo
    module procedure foo_proc
  end interface
contains
  function foo_proc(i) result(this)
    integer, intent(in) :: i
    type(foo) :: this
    this%i = i
    write(*, *) 'Hello'
  end function
end module m
program p
  use m
  implicit none
  o_foo = foo(2)
end program

QUESTION:

Is this program standard conforming?

DISCUSSION:

R525 establishes that an accessibility statement may refer to a
use-name or a generic-spec. It appears that the situation where
use-name and generic-spec are identical, but are intended to have
different accessibility, has not been dealt with.

ANSWER 1:

No, it was not intended that a generic with the same name as
a derived type could have a different accessibility than that
of the derived type. Therefore the above program is not standard
conforming.

ANSWER 2:

Yes, the program is standard conforming. Since it is possible to
define PUBLIC entities of PRIVATE type, it is desirable to be able
to use a generic such as that defined in the example program, and
the PUBLIC :: FOO statement refers to the generic procedure FOO.


Unfortunately, it is not very clear to me how any of these answers
should be described in the standard, since it appears (after a moderate
amount of searching) that no provisions are in place which
prevent an entity being equipped with contradicting accessibility
attributes via an attribute and a statement, respectively.



SUBMITTED BY: R. Bader

HISTORY: Submitted September 27, 2010