message: trivial char range check
diff: @@ -298,11 +298,11 @@ impl<'a> Iterator for Tokenizer<'a> {
  }
  fn is_ident_start(ch: char) -> bool {
  - ch == '_' || ('a' <= ch && ch <= 'z') || ('A' <= ch && ch <= 'Z')
  + ch == '_' || ch.is_ascii_alphabetic()
  }
  fn is_ident_rest(ch: char) -> bool {
  - is_ident_start(ch) || ('0' <= ch && ch <= '9')
  + is_ident_start(ch) || ch.is_ascii_digit()
  }
  impl<'a> Token<'a> {
  