Bug in Fortran-95 compiler (Linux-x86, compiler 8.3, dated 2009/03/06)

Question

The following test code is incorrectly flagged as being in error:
module confuse
  implicit none
  interface submod
     module procedure suba
     module procedure subb
  end interface
contains
  subroutine suba(nz,info,n)
    integer, intent (in) :: nz
    integer, intent (out) :: info
    integer, optional, intent (in) :: n
    info = 0
  end subroutine suba
  subroutine subb(n,nz,info,m)
    integer, intent (in) :: n, nz,m
    integer, intent (out) :: info
    integer :: nzz
    info = 0
    nzz = 0
    call suba(nzz,info,n = n)
  end subroutine subb
end module confuse
module deps
use confuse
contains
  subroutine prolng(ierr)
  integer, intent(inout) :: ierr
  integer :: cnvtx=2
  integer :: nz=0
  integer :: info
  ierr=0
  call submod(nz,info,n=cnvtx)
  if(info.ne.0)ierr=1
  return
  end subroutine prolng
end module depsThe error message is
"ambig.f90", Line = 35, Column = 25: ERROR: More than one actual argument has been specified for a dummy argument.
The message goes away if the keyword argument name is changed from 'n' to something else, such as 'ni'.

Answer 1

About a month ago, I reported this bug to Sun through the prescribed bug report Web interface, and received an automated reply announcing internal review ID of 1464791. However, there was no follow-up E-mail acknowledging the recognition of the bug and a bug number.
Sorry, I do not have a paid support subscription.