Typing fixes to eliminate casts/dcalls

test/generated_sdk/lib/collection/linked_hash_map.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 hash-table based implementation of [Map].
  *
  * The insertion order of keys is remembered,
@@ skipping 37 matching lines @@
    * of an object, or what it compares equal to, should not change while the
    * object is in the table. If it does change, the result is unpredictable.
    *
    * 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 [LinkedHashMap.identity]).
    */
   factory LinkedHashMap({ bool equals(K key1, K key2),
                           int hashCode(K key),
-                          bool isValidKey(potentialKey) }) {
+                          bool isValidKey(Object potentialKey) }) {
     if (isValidKey == null) {
       if (hashCode == null) {
         if (equals == null) {
           return new _LinkedHashMap<K, V>();
         }
         hashCode = _defaultHashCode;
       } else {
         if (identical(identityHashCode, hashCode) &&
             identical(identical, equals)) {
           return new _LinkedIdentityHashMap<K, V>();
@@ skipping 71 matching lines @@
   @NoInline()
   factory LinkedHashMap._literal(List keyValuePairs) {
     return fillLiteralMap(keyValuePairs, new _LinkedHashMap<K, V>());
   }
 
   @NoThrows() @NoInline()
   factory LinkedHashMap._empty() {
     return new _LinkedHashMap<K, V>();
   }
 }