To:       J3                                                 08-162r1
From:     Jim Xia/Bill Long
Subject:  Comment: allocatable coarray and non-coarray allocatable dummy
Date: 2008 May 12
References: J3/08-007r2 (WG5/N1723)


DISCUSSION:

It seems that N1723 allows an allocatable coarray to be associated
with a non-coarray allocatable dummy. Consider the following sample
program

real, allocatable :: x(:)[:]
call sub (x)                  !<-- this should be disallowed
...
subroutine sub (y)
  real, allocatable :: y(:)
...
end subroutine

Since subroutine sub expects a non-coarray allocatable dummy, it could
allocate or deallocate the dummy argument, which causes implicit
synchronizations on the actual argument. This call should not be
allowed.

EDITS to J3/08-007r2:

[292:12.5.2.6p2+] After the second paragraph of 12.5.2.6 "Allocatable
      dummy variables", insert a new paragraph:

"If the dummy argument is not a coarray, the actual argument shall not
be a coarray."