Allow Object when doing lookups.

sdk/lib/collection/list.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;
 
 /**
  * Abstract implementation of a list.
  *
  * All operations are defined in terms of `length`, `operator[]`,
@@ skipping 45 matching lines @@
     if (length == 0) throw new StateError("No elements");
     return this[length - 1];
   }
 
   E get single {
     if (length == 0) throw new StateError("No elements");
     if (length > 1) throw new StateError("Too many elements");
     return this[0];
   }
 
-  bool contains(E element) {
+  bool contains(Object element) {
     int length = this.length;
     for (int i = 0; i < length; i++) {
       if (this[i] == element) return true;
       if (length != this.length) {
         throw new ConcurrentModificationError(this);
       }
     }
     return false;
   }
 
@@ skipping 12 matching lines @@
     int length = this.length;
     for (int i = 0; i < length; i++) {
       if (test(this[i])) return true;
       if (length != this.length) {
         throw new ConcurrentModificationError(this);
       }
     }
     return false;
   }
 
-  E firstWhere(bool test(E element), { E orElse() }) {
+  dynamic firstWhere(bool test(E element), { Object orElse() }) {
     int length = this.length;
     for (int i = 0; i < length; i++) {
       E element = this[i];
       if (test(element)) return element;
       if (length != this.length) {
         throw new ConcurrentModificationError(this);
       }
     }
     if (orElse != null) return orElse();
     throw new StateError("No matching element");
   }
 
-  E lastWhere(bool test(E element), { E orElse() }) {
+  dynamic lastWhere(bool test(E element), { Object orElse() }) {
     int length = this.length;
     for (int i = length - 1; i >= 0; i--) {
       E element = this[i];
       if (test(element)) return element;
       if (length != this.length) {
         throw new ConcurrentModificationError(this);
       }
     }
     if (orElse != null) return orElse();
     throw new StateError("No matching element");
@@ skipping 255 matching lines @@
       }
     }
   }
 
   void replaceRange(int start, int end, Iterable<E> newContents) {
     // TODO(floitsch): Optimize this.
     removeRange(start, end);
     insertAll(start, newContents);
   }
 
-  int indexOf(E element, [int startIndex = 0]) {
+  int indexOf(Object element, [int startIndex = 0]) {
     if (startIndex >= this.length) {
       return -1;
     }
     if (startIndex < 0) {
       startIndex = 0;
     }
     for (int i = startIndex; i < this.length; i++) {
       if (this[i] == element) {
         return i;
       }
     }
     return -1;
   }
 
   /**
    * Returns the last index in the list [a] of the given [element], starting
    * the search at index [startIndex] to 0.
    * Returns -1 if [element] is not found.
    */
-  int lastIndexOf(E element, [int startIndex]) {
+  int lastIndexOf(Object element, [int startIndex]) {
     if (startIndex == null) {
       startIndex = this.length - 1;
     } else {
       if (startIndex < 0) {
         return -1;
       }
       if (startIndex >= this.length) {
         startIndex = this.length - 1;
       }
     }
@@ skipping 53 matching lines @@
       for (E element in iterable) {
         this[index++] = element;
       }
     }
   }
 
   Iterable<E> get reversed => new ReversedListIterable(this);
 
   String toString() => ToString.iterableToString(this);
 }