program main

    ! labelled without enddo (normal)
    do 10 i = 0, 5
      acc = acc + 1
10  continue

    ! multiple labelled sharing same non-enddo final
    do 20 i = 0, 3
      do 20 j = 0, 5
20      print *, "ok"

    ! multiple labelled AND named sharing same non-enddo final
    ! TODO: I can't tell if labelled+named is in the spec. We don't support it
    ! for now, though it's probably? pretty easy.
!    outer: do 25 i = 0, 3
!      inner: do 25 j = 0, 5
!25      print *, "ok"

    ! labelled but using END DO (F90 unusual)
    ! NOTE: This is the main problematic construction. END DOs can also end
    ! nonblock DOs, so we're stuffed. We get reduce-reduce errors in Happy, and
    ! I don't know of a way to reconcile them. We'd need to select one of two
    ! rules (with wildly different types) for the same expansion, depending on
    ! context. I don't think Happy is that.
    do 30 i = 0, 42
      print *, i
30  end do

    ! unlabelled (F90 normal)
    do i = 0, 42
      print *,i
    end do

    ! unlabelled using enddo (normal)
    end program main