void assertMatches(@NotNull CharSequence text, @NotNull Lexer lexer) {
    TokenSequence sequence = new Builder(text, lexer).performLexing();
    assert lexemeCount == sequence.lexemeCount;
    for(int j = 0; j <= lexemeCount; ++j) {
      if (sequence.lexStarts[j] != lexStarts[j] || sequence.lexTypes[j] != lexTypes[j]) {
        assert false;
      }
    }
  }
void assertMatches(@NotNull CharSequence text, @NotNull Lexer lexer)