message: Fix cfg(not(procmacro2_semver_exempt))
diff: @@ -33,7 +33,7 @@ fn get_joinned_span(t: &ToTokens) -> Span {
  #[cfg(not(procmacro2_semver_exempt))]
  fn get_joinned_span(t: &ToTokens) -> Span {
  let tts: TokenStream = t.dump().into();
  - let (mut first, last) = (None, None);
  + let mut first = None;
  for tt in tts {
  match first {
  None => first = Some(tt.span()),
  