anchor.diff:    /// ;
     /// ```
     Token parseBlock(Token token) {
  -    Token begin = token = ensureBlock(token);
  +    Token begin = token = ensureBlock(token, null);
       listener.beginBlock(begin);
       int statementCount = 0;
       while (notEofOrValue('}', token.next)) {
  
positive.code:   }
  
    Token skipBlock(Token token) {
      token = ensureBlock(token);
      Token closeBrace = closeBraceTokenFor(token);
      if (closeBrace == null ||
          !identical(closeBrace.kind, $CLOSE_CURLY_BRACKET)) {
  
negative.code:     Token begin = next;
      int statementCount = 0;
      if (!optional('{', next)) {
        token = ensureBlock(token, fasta.templateExpectedFunctionBody);
        listener.handleInvalidFunctionBody(token);
        return token.endGroup;
      }
  