anchor.diff:    }
   
     /**
  -   * Given a list of arguments and the element that will be invoked using those argument, compute
  -   * the list of parameters that correspond to the list of arguments. Return the parameters that
  -   * correspond to the arguments, or `null` if no correspondence could be computed.
  -   *
  -   * @param reportError if `true` then compile-time error should be reported; if `false`
  -   *          then compile-time warning
  -   * @param argumentList the list of arguments being passed to the element
  -   * @param executableElement the element that will be invoked with the arguments
  -   * @return the parameters that correspond to the arguments
  +   * Given an [argumentList] and the [executableElement] that will be invoked
  +   * using those argument, compute the list of parameters that correspond to the
  +   * list of arguments. An error will be reported if any of the arguments cannot
  +   * be matched to a parameter. The flag [reportError] should be `true` if a
  +   * compile-time error should be reported; or `false` if a compile-time warning
  +   * should be reported. Return the parameters that correspond to the arguments,
  +   * or `null` if no correspondence could be computed.
      */
     List<ParameterElement> _resolveArgumentsToFunction(bool reportError,
         ArgumentList argumentList, ExecutableElement executableElement) {
  
positive.code:           //
            ClassElement enclosingClass = _resolver.enclosingClass;
            if (enclosingClass != null) {
              setter = _lookUpSetter(null, enclosingClass.type, node.name);
            }
          }
          if (setter != null) {
  
negative.code:   }
  
    /**
     * Look up the getter with the given [getterName] in the given [type]. Return
     * the element representing the getter that was found, or `null` if there is
     * no getter with the given name. The [target] is the target of the
     * invocation, or `null` if there is no target.
     */
    PropertyAccessorElement _lookUpGetter(
        Expression target, DartType type, String getterName) {
  