Typing fixes to eliminate casts/dcalls

test/generated_sdk/lib/collection/collection.dart

 // Copyright (c) 2012, 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.
 
 /**
  * Classes and utilities that supplement the collection support in dart:core.
  */
 library dart.collection;
 
 import 'dart:_internal';
@@ skipping 348 matching lines @@
     int length = JS('int', '#.length', bucket);
     for (int i = 0; i < length; i += 2) {
       if (identical(JS('var', '#[#]', bucket, i), key)) return i;
     }
     return -1;
   }
 }
 class _CustomHashMap<K, V> extends _HashMap<K, V> {
   final _Equality<K> _equals;
   final _Hasher<K> _hashCode;
-  final _Predicate _validKey;
-  _CustomHashMap(this._equals, this._hashCode, bool validKey(potentialKey))
+  final _Predicate<Object> _validKey;
+  _CustomHashMap(this._equals, this._hashCode,
+                 bool validKey(Object potentialKey))
       : _validKey = (validKey != null) ? validKey : ((v) => v is K);
 
   V operator[](Object key) {
     if (!_validKey(key)) return null;
     return super._get(key);
   }
 
   void operator[]=(K key, V value) {
     super._set(key, value);
   }
@@ skipping 400 matching lines @@
     for (int i = 0; i < length; i++) {
       LinkedHashMapCell cell = JS('var', '#[#]', bucket, i);
       if (identical(cell._key, key)) return i;
     }
     return -1;
   }
 }
 class _LinkedCustomHashMap<K, V> extends _LinkedHashMap<K, V> {
   final _Equality<K> _equals;
   final _Hasher<K> _hashCode;
-  final _Predicate _validKey;
+  final _Predicate<Object> _validKey;
   _LinkedCustomHashMap(this._equals, this._hashCode,
-                       bool validKey(potentialKey))
+                       bool validKey(Object potentialKey))
       : _validKey = (validKey != null) ? validKey : ((v) => v is K);
 
   V operator[](Object key) {
     if (!_validKey(key)) return null;
     return super._get(key);
   }
 
   void operator[]=(K key, V value) {
     super._set(key, value);
   }
@@ skipping 376 matching lines @@
     int length = JS('int', '#.length', bucket);
     for (int i = 0; i < length; i++) {
       if (identical(JS('var', '#[#]', bucket, i), element)) return i;
     }
     return -1;
   }
 }
 class _CustomHashSet<E> extends _HashSet<E> {
   _Equality<E> _equality;
   _Hasher<E> _hasher;
-  _Predicate _validKey;
-  _CustomHashSet(this._equality, this._hasher, bool validKey(potentialKey))
+  _Predicate<Object> _validKey;
+  _CustomHashSet(this._equality, this._hasher,
+                 bool validKey(Object potentialKey))
       : _validKey = (validKey != null) ? validKey : ((x) => x is E);
 
   Set<E> _newSet() => new _CustomHashSet<E>(_equality, _hasher, _validKey);
 
   int _findBucketIndex(var bucket, var element) {
     if (bucket == null) return -1;
     int length = JS('int', '#.length', bucket);
     for (int i = 0; i < length; i++) {
       if (_equality(JS('var', '#[#]', bucket, i), element)) return i;
     }
@@ skipping 379 matching lines @@
     for (int i = 0; i < length; i++) {
       LinkedHashSetCell cell = JS('var', '#[#]', bucket, i);
       if (identical(cell._element, element)) return i;
     }
     return -1;
   }
 }
 class _LinkedCustomHashSet<E> extends _LinkedHashSet<E> {
   _Equality<E> _equality;
   _Hasher<E> _hasher;
-  _Predicate _validKey;
+  _Predicate<Object> _validKey;
   _LinkedCustomHashSet(this._equality, this._hasher,
-                       bool validKey(potentialKey))
+                       bool validKey(Object potentialKey))
       : _validKey = (validKey != null) ? validKey : ((x) => x is E);
 
   Set<E> _newSet() =>
       new _LinkedCustomHashSet<E>(_equality, _hasher, _validKey);
 
   int _findBucketIndex(var bucket, var element) {
     if (bucket == null) return -1;
     int length = JS('int', '#.length', bucket);
     for (int i = 0; i < length; i++) {
       LinkedHashSetCell cell = JS('var', '#[#]', bucket, i);
@@ skipping 68 matching lines @@
     } else if (_cell == null) {
       _current = null;
       return false;
     } else {
       _current = _cell._element;
       _cell = _cell._next;
       return true;
     }
   }
 }