message: Use span.len() instead of our own version
  Summary: Better to use the built-in helpers
diff: @@ -81,7 +81,7 @@ pub(crate) fn parse_error_add_span(
  token: (x, .., y), ..
  } => span.subspan(*x as u64, *y as u64),
  lu::ParseError::UnrecognizedEOF { .. } => {
  - let x = span.high() - span.low();
  + let x = span.len();
  span.subspan(x, x)
  }
  lu::ParseError::ExtraToken { token: (x, .., y) } => span.subspan(*x as u64, *y as u64),
  