anchor.diff:      push(ast.blockFunctionBody(asyncKeyword, star, block));
     }
   
  -  void finishFunction(annotations, formals, asyncModifier, FunctionBody body) {
  +  void finishFunction(
  +      List annotations, formals, AsyncMarker asyncModifier, FunctionBody body) {
       debugEvent("finishFunction");
   
       Statement bodyStatement;
  
positive.code: 
    @override
    void handleImportPrefix(Token deferredKeyword, Token asKeyword) {
      debugEvent("ImportPrefix");
      if (asKeyword == null) {
        // If asKeyword is null, then no prefix has been pushed on the stack.
        // Push a placeholder indicating that there is no prefix.
  
negative.code:   }
  
    @override
    void endYieldStatement(Token yieldToken, Token starToken, Token semicolon) {
      assert(optional('yield', yieldToken));
      assert(optionalOrNull('*', starToken));
      assert(optional(';', semicolon));
      debugEvent("YieldStatement");
  
      Expression expression = pop();
      push(ast.yieldStatement(yieldToken, starToken, expression, semicolon));
    }
  
    @override
  