Make IterableMixinWorkaround using classes return correctly typed Iterables.

runtime/lib/array.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.
 
 
 // TODO(srdjan): Use shared array implementation.
 class _List<E> implements List<E> {
 
   factory _List(length) native "List_allocate";
 
@@ skipping 35 matching lines @@
 
   void removeWhere(bool test(E element)) {
     throw NonGrowableListError.remove();
   }
 
   void retainWhere(bool test(E element)) {
     throw NonGrowableListError.remove();
   }
 
   Iterable<E> getRange(int start, [int end]) {
-    return IterableMixinWorkaround.getRangeList(this, start, end);
+    return new IterableMixinWorkaround<E>().getRangeList(this, start, end);
   }
 
   // List interface.
   void setRange(int start, int end, Iterable<E> iterable, [int skipCount = 0]) {
     if (start < 0 || start > this.length) {
       throw new RangeError.range(start, 0, this.length);
     }
     if (end < start || end > this.length) {
       throw new RangeError.range(end, start, this.length);
     }
@@ skipping 62 matching lines @@
 
   E reduce(E combine(E value, E element)) {
     return IterableMixinWorkaround.reduce(this, combine);
   }
 
   fold(initialValue, combine(previousValue, E element)) {
     return IterableMixinWorkaround.fold(this, initialValue, combine);
   }
 
   Iterable<E> where(bool f(E element)) {
-    return IterableMixinWorkaround.where(this, f);
+    return new IterableMixinWorkaround<E>().where(this, f);
   }
 
   Iterable expand(Iterable f(E element)) {
     return IterableMixinWorkaround.expand(this, f);
   }
 
   Iterable<E> take(int n) {
-    return IterableMixinWorkaround.takeList(this, n);
+    return new IterableMixinWorkaround<E>().takeList(this, n);
   }
 
   Iterable<E> takeWhile(bool test(E value)) {
-    return IterableMixinWorkaround.takeWhile(this, test);
+    return new IterableMixinWorkaround<E>().takeWhile(this, test);
   }
 
   Iterable<E> skip(int n) {
-    return IterableMixinWorkaround.skipList(this, n);
+    return new IterableMixinWorkaround<E>().skipList(this, n);
   }
 
   Iterable<E> skipWhile(bool test(E value)) {
-    return IterableMixinWorkaround.skipWhile(this, test);
+    return new IterableMixinWorkaround<E>().skipWhile(this, test);
   }
 
   bool every(bool f(E element)) {
     return IterableMixinWorkaround.every(this, f);
   }
 
   bool any(bool f(E element)) {
     return IterableMixinWorkaround.any(this, f);
   }
 
@@ skipping 12 matching lines @@
   E elementAt(int index) {
     return this[index];
   }
 
   bool get isEmpty {
     return this.length == 0;
   }
 
   bool get isNotEmpty => !isEmpty;
 
-  Iterable<E> get reversed => IterableMixinWorkaround.reversedList(this);
+  Iterable<E> get reversed =>
+      new IterableMixinWorkaround<E>().reversedList(this);
 
   void sort([int compare(E a, E b)]) {
     IterableMixinWorkaround.sortList(this, compare);
   }
 
   void shuffle([Random random]) {
     IterableMixinWorkaround.shuffleList(this, random);
   }
 
   int indexOf(Object element, [int start = 0]) {
@@ skipping 47 matching lines @@
 
   List<E> toList({ bool growable: true}) {
     return new List<E>.from(this, growable: growable);
   }
 
   Set<E> toSet() {
     return new Set<E>.from(this);
   }
 
   Map<int, E> asMap() {
-    return IterableMixinWorkaround.asMapList(this);
+    return new IterableMixinWorkaround<E>().asMapList(this);
   }
 }
 
 
 // This is essentially the same class as _List, but it does not
 // permit any modification of array elements from Dart code. We use
 // this class for arrays constructed from Dart array literals.
 // TODO(hausner): We should consider the trade-offs between two
 // classes (and inline cache misses) versus a field in the native
 // implementation (checks when modifying). We should keep watching
@@ skipping 69 matching lines @@
     if (end == null) end = this.length;
     int length = end - start;
     if (start == end) return [];
     List list = new List<E>();
     list.length = length;
     Lists.copy(this, start, list, 0, length);
     return list;
   }
 
   Iterable<E> getRange(int start, int end) {
-    return IterableMixinWorkaround.getRangeList(this, start, end);
+    return new IterableMixinWorkaround<E>().getRangeList(this, start, end);
   }
 
   // Collection interface.
 
   bool contains(Object element) {
     return IterableMixinWorkaround.contains(this, element);
   }
 
   void forEach(f(E element)) {
     IterableMixinWorkaround.forEach(this, f);
   }
 
   Iterable map(f(E element)) {
     return IterableMixinWorkaround.mapList(this, f);
   }
 
   String join([String separator = ""]) {
     return IterableMixinWorkaround.joinList(this, separator);
   }
 
   E reduce(E combine(E value, E element)) {
     return IterableMixinWorkaround.reduce(this, combine);
   }
 
   fold(initialValue, combine(previousValue, E element)) {
     return IterableMixinWorkaround.fold(this, initialValue, combine);
   }
 
   Iterable<E> where(bool f(E element)) {
-    return IterableMixinWorkaround.where(this, f);
+    return new IterableMixinWorkaround<E>().where(this, f);
   }
 
   Iterable expand(Iterable f(E element)) {
     return IterableMixinWorkaround.expand(this, f);
   }
 
   Iterable<E> take(int n) {
-    return IterableMixinWorkaround.takeList(this, n);
+    return new IterableMixinWorkaround<E>().takeList(this, n);
   }
 
   Iterable<E> takeWhile(bool test(E value)) {
-    return IterableMixinWorkaround.takeWhile(this, test);
+    return new IterableMixinWorkaround<E>().takeWhile(this, test);
   }
 
   Iterable<E> skip(int n) {
-    return IterableMixinWorkaround.skipList(this, n);
+    return new IterableMixinWorkaround<E>().skipList(this, n);
   }
 
   Iterable<E> skipWhile(bool test(E value)) {
-    return IterableMixinWorkaround.skipWhile(this, test);
+    return new IterableMixinWorkaround<E>().skipWhile(this, test);
   }
 
   bool every(bool f(E element)) {
     return IterableMixinWorkaround.every(this, f);
   }
 
   bool any(bool f(E element)) {
     return IterableMixinWorkaround.any(this, f);
   }
 
@@ skipping 12 matching lines @@
   E elementAt(int index) {
     return this[index];
   }
 
   bool get isEmpty {
     return this.length == 0;
   }
 
   bool get isNotEmpty => !isEmpty;
 
-  Iterable<E> get reversed => IterableMixinWorkaround.reversedList(this);
+  Iterable<E> get reversed =>
+      new IterableMixinWorkaround<E>().reversedList(this);
 
   void sort([int compare(E a, E b)]) {
     throw UnmodifiableListError.change();
   }
 
   void shuffle([Random random]) {
     throw UnmodifiableListError.change();
   }
 
   String toString() {
@@ skipping 51 matching lines @@
 
   List<E> toList({ bool growable: true }) {
     return new List<E>.from(this, growable: growable);
   }
 
   Set<E> toSet() {
     return new Set<E>.from(this);
   }
 
   Map<int, E> asMap() {
-    return IterableMixinWorkaround.asMapList(this);
+    return new IterableMixinWorkaround<E>().asMapList(this);
   }
 }
 
 
 // Iterator for arrays with fixed size.
 class _FixedSizeArrayIterator<E> implements Iterator<E> {
   final List<E> _array;
   final int _length;  // Cache array length for faster access.
   int _position;
   E _current;
@@ skipping 12 matching lines @@
     }
     _position = _length;
     _current = null;
     return false;
   }
 
   E get current {
     return _current;
   }
 }