anchor.diff:    }
   
     return null;
  -}
  +}
positive.code: List _canonicalizeArray(List array, map) =>
      _memoizeArray(map, array, () => array);
  
  // TODO(leafp): This only canonicalizes of the names are
  // emitted in a consistent order.
  _canonicalizeNamed(named, map) => JS('', '''(() => {
    let key = [];
    let names = $getOwnPropertyNames($named);
  
negative.code:   Type get runtimeType => Type;
  }
  
  /// Given an internal runtime type object [type], wraps it in a `_Type` object
  /// that implements the dart:core Type interface.
  ///
  /// [isNormalized] is true when [type] is known to be in a canonicalized
  /// normal form, so the algorithm can directly wrap and return the value.
  Type wrapType(type, {isNormalized = false}) {
    // If we've already wrapped this type once, use the previous wrapper. This
    // way, multiple references to the same type return an identical Type.
    if (JS('!', '#.hasOwnProperty(#)', type, _typeObject)) {
  