automatic coarray object with Intel Fortran

[DataScientist]

The Fortran standard, as far as I am aware, prohibits the use of automatic coarrays. However, I have noticed that Intel Fortran compiler 2018, allows such automatic object creations. For example, ifort happily compiles the following code in the debug mode and the code works totally fine:

program testAutoCoarray

implicit none

integer :: i
integer, parameter :: nd=10

call createAutoCoarray(nd)

end program testAutoCoarray

subroutine createAutoCoarray(nd)
  implicit none
  integer, intent(in) :: nd
  real, save :: AutoCoarray(nd)

  if (this_image()==1) then
    AutoCoarray = -13.e0
    sync images(*)
  else
    AutoCoarray = AutoCoarray(:)[1]
    sync images(1)
  end if
  write(*,"(*(g0.4,' '))") this_image(), AutoCoarray
end subroutine createAutoCoarray

Have I understood the Fortran 2008 standard incorrectly, or this is a bug in ifort. It is notable that ifort crashes with catastrophic internal error if I attempt to compile the same code as above in O2 or O3 modes. Here is the message:

E:\testAutomaticCoarray>ifort /O2 /Qcoarray=shared /standard-semantics /assume:realloc_lhs main.f90 -o run.exe
Intel(R) Visual Fortran Intel(R) 64 Compiler for applications running on Intel(R) 64, Version 18.0.1.156 Build 20171018
Copyright (C) 1985-2017 Intel Corporation.  All rights reserved.

0_8000

E:\testAutomaticCoarray\main.f90(12): catastrophic error: **Internal compiler error: internal abort** Please report this error along with the circumstances in which it occurred in a Software Problem Report.  Note: File and line given may not be explicit cause of this error.
compilation aborted for main.f90 (code 1)

Thank you for your help and great work!

[Steve_Lionel · Accepted solution]

The compiler should never have allowed this. AutoCoarray can't be automatic, because it has the SAVE attribute. But then it has a specification expression for bounds, which makes it automatic.

There is no explicit prohibition of an "automatic coarray", but the requirement that a coarray be "an associate name, a dummy argument, or have the ALLOCATABLE or SAVE attribute" effectively eliminates that possibility.

Please report this bug to Intel at https://supporttickets.intel.com/?lang=en-US

[DataScientist]

Dear Steve, I reported the bug. Your comments are always very informative, thanks!