anchor.diff:      call segment_intersection( &
            segment_start, segment_end, line_start, line_end, &
            s_curr, t_curr, success)
  -    call in_interval(s_curr, 0.0_dp, 1.0_dp, predicate1)
  -    call in_interval(t_curr, 0.0_dp, 1.0_dp, predicate2)
  -    if (success .AND. predicate1 .AND. predicate2) then
  +    if ( &
  +         success .AND. &
  +         in_interval(s_curr, 0.0_dp, 1.0_dp) .AND. &
  +         in_interval(t_curr, 0.0_dp, 1.0_dp)) then
          enum_ = BoxIntersectionType_INTERSECTION
          return
       end if
  
positive.code:     call segment_intersection( &
           segment_start, segment_end, line_start, line_end, &
           s_curr, t_curr, success)
      call in_interval(s_curr, 0.0_dp, 1.0_dp, predicate1)
      call in_interval(t_curr, 0.0_dp, 1.0_dp, predicate2)
      if (success .AND. predicate1 .AND. predicate2) then
         enum_ = BoxIntersectionType_INTERSECTION
         return
      end if
  
negative.code:     call segment_intersection( &
           segment_start, segment_end, line_start, line_end, &
           s_curr, t_curr, success)
      if ( &
           success .AND. &
           in_interval(s_curr, 0.0_dp, 1.0_dp) .AND. &
           in_interval(t_curr, 0.0_dp, 1.0_dp)) then
         enum_ = BoxIntersectionType_INTERSECTION
         return
      end if
  