anchor.diff:    }
   
     Future<void> _addProposal_assignToLocalVariable() async {
  -    // TODO(brianwilkerson) Determine whether this await is necessary.
  -    await null;
       // prepare enclosing ExpressionStatement
       ExpressionStatement expressionStatement;
       for (AstNode node = this.node; node != null; node = node.parent) {
  
positive.code:   }
  
    Future<void> _addProposal_convertToForIndexLoop() async {
      // TODO(brianwilkerson) Determine whether this await is necessary.
      await null;
      // find enclosing ForEachStatement
      ForStatement forEachStatement = node.thisOrAncestorMatching(
          (node) => node is ForStatement && node.forLoopParts is ForEachParts);
  
negative.code:   }
  
    Future<void> _addProposal_replaceIfElseWithConditional() async {
      // should be "if"
      if (node is! IfStatement) {
        _coverageMarker();
  