anchor.diff:  
     // GenericFunctionTypeIdentifiers are implicitly normalized.
     if (JS<bool>('!', '# instanceof #', type, GenericFunctionTypeIdentifier)) {
  -    return wrapType(type, isNormalized: true);
  +    return wrapType(type, true);
     }
     if (JS<bool>('!', '# instanceof #', type, FunctionType)) {
       var normReturnType = normalizeHelper(type.returnType);
  
positive.code: ///
  /// [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)) {
  
negative.code:     var normArgs = args.map(normalizeHelper).toList();
      normType = JS('!', '#(...#)', genericClass, normArgs);
    }
    return wrapType(normType, true);
  }
  
  /// Generates new values by applying [transform] to the values of [srcObject],
  