Typing fixes to eliminate casts/dcalls

test/generated_sdk/lib/collection/linked_hash_set.dart

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 part of dart.collection;
 
 /**
  * A [LinkedHashSet] is a hash-table based [Set] implementation.
  *
  * The `LinkedHashSet` also keep track of the order that elements were inserted
@@ skipping 36 matching lines @@
    * If [isValidKey] is omitted, it defaults to testing if the object is an
    * [E] instance.
    *
    * If you supply one of [equals] and [hashCode],
    * you should generally also to supply the other.
    * An example would be using [identical] and [identityHashCode],
    * which is equivalent to using the shorthand [LinkedSet.identity]).
    */
   factory LinkedHashSet({ bool equals(E e1, E e2),
                           int hashCode(E e),
-                          bool isValidKey(potentialKey) }) {
+                          bool isValidKey(Object potentialKey) }) {
     if (isValidKey == null) {
       if (hashCode == null) {
         if (equals == null) {
           return new _LinkedHashSet<E>();
         }
         hashCode = _defaultHashCode;
       } else {
         if (identical(identityHashCode, hashCode) &&
             identical(identical, equals)) {
           return new _LinkedIdentityHashSet<E>();
@@ skipping 49 matching lines @@
    *
    * The elements are iterated in insertion order.
    */
   void forEach(void action(E element));
 
   /**
    * Provides an iterator that iterates over the elements in insertion order.
    */
   Iterator<E> get iterator;
 }