anchor.diff:      return result;
     }
   
  -  bool blockBody(Statement body, {bool needsSeparation}) {
  +  bool blockBody(Statement body, {required bool needsSeparation}) {
       if (body is Block) {
         blockOut(body);
         return true;
  
positive.code:     node.accept(this);
    }
  
    void visitCommaSeparated(List<Node> nodes, int hasRequiredType,
        {bool newInForInit, bool newAtStatementBegin}) {
      for (int i = 0; i < nodes.length; i++) {
        if (i != 0) {
          atStatementBegin = false;
  
negative.code:     blockBody(body, needsSeparation: false);
    }
  
    int functionOut(Fun fun, Expression? name, VarCollector vars) {
      out('function'); // 'function'
      if (name != null) {
        out(' '); // ' '
  