[Bug fortran/83436] New: Internal file cannot be accessed by UNFORMATTED data transfer when reading from /dev/urandom

["daanvanvugt at gmail dot com" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83436

            Bug ID: 83436
           Summary: Internal file cannot be accessed by UNFORMATTED data
                    transfer when reading from /dev/urandom
           Product: gcc
           Version: 7.2.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: fortran
          Assignee: unassigned at gcc dot gnu.org
          Reporter: daanvanvugt at gmail dot com
  Target Milestone: ---

With the update to 7.2.1 the following code fragment starts failing:
Fortran runtime error: Internal file cannot be accessed by UNFORMATTED data
transfer


  !> Read an int from /dev/urandom
  subroutine read_urandom_int(seed, ierr)
    implicit none
    integer, intent(out) :: seed
    integer, intent(out) :: ierr
    integer :: un

    open(newunit=un, file="/dev/urandom", access="stream", &
        form="unformatted", action="read", status="old", iostat=ierr)
    if (ierr == 0) then
      read(un) seed
      close(un)
    end if
  end subroutine read_urandom_int

I think this might be a regression. The same code works just fine in intel
compiler and older gfortran versions.