diff --git a/pkg/compiler/lib/src/helpers/debug_collection.dart b/pkg/compiler/lib/src/helpers/debug_collection.dart
index 2ec5eb9d624..03ac0e9edc2 100644
--- a/pkg/compiler/lib/src/helpers/debug_collection.dart
+++ b/pkg/compiler/lib/src/helpers/debug_collection.dart
@@ -21,12 +21,10 @@ class DebugMap<K, V> implements Map<K, V> {
     putIfAbsentCallback = value;
   }
 
-  Map<RK, RV> cast<RK, RV>() {
-    Map<Object, Object> self = this;
-    return self is Map<RK, RV> ? self : this.retype<RK, RV>();
-  }
+  Map<RK, RV> cast<RK, RV>() => Map.castFrom<K, V, RK, RV>(this);
 
-  Map<RK, RV> retype<RK, RV>() => Map.castFrom<K, V, RK, RV>(this);
+  @Deprecated("Use cast instead.")
+  Map<RK, RV> retype<RK, RV>() => cast<RK, RV>();
 
   bool containsValue(Object value) {
     return sourceMap.containsValue(value);
@@ -109,12 +107,10 @@ class DebugIterable<E> implements Iterable<E> {
 
   Iterator<E> get iterator => iterable.iterator;
 
-  Iterable<R> cast<R>() {
-    Iterable<Object> self = this;
-    return self is Iterable<R> ? self : this.retype<R>();
-  }
+  Iterable<R> cast<R>() => Iterable.castFrom<E, R>(this);
 
-  Iterable<R> retype<R>() => Iterable.castFrom<E, R>(this);
+  @Deprecated("Use cast instead.")
+  Iterable<R> retype<R>() => cast<R>();
 
   Iterable<T> map<T>(T f(E element)) => iterable.map(f);
 
@@ -193,12 +189,10 @@ class DebugList<E> extends DebugIterable<E> implements List<E> {
 
   List<E> get list => iterable;
 
-  List<R> cast<R>() {
-    List<Object> self = this;
-    return self is List<R> ? self : this.retype<R>();
-  }
+  List<R> cast<R>() => List.castFrom<E, R>(this);
 
-  List<R> retype<R>() => List.castFrom<E, R>(this);
+  @Deprecated("Use cast instead.")
+  List<R> retype<R>() => cast<R>();
 
   List<E> operator +(List<E> other) => list + other;
 
@@ -302,12 +296,10 @@ class DebugSet<E> extends DebugIterable<E> implements Set<E> {
 
   Set<E> get set => iterable;
 
-  Set<R> cast<R>() {
-    Set<Object> self = this;
-    return self is Set<R> ? self : this.retype<R>();
-  }
+  Set<R> cast<R>() => Set.castFrom<E, R>(this);
 
-  Set<R> retype<R>() => Set.castFrom<E, R>(this);
+  @Deprecated("Use cast instead.")
+  Set<R> retype<R>() => cast<R>();
 
   bool contains(Object value) => set.contains(value);
 
diff --git a/pkg/compiler/lib/src/helpers/expensive_map.dart b/pkg/compiler/lib/src/helpers/expensive_map.dart
index 35001e4017a..48be3849459 100644
--- a/pkg/compiler/lib/src/helpers/expensive_map.dart
+++ b/pkg/compiler/lib/src/helpers/expensive_map.dart
@@ -68,12 +68,10 @@ class ExpensiveMap<K, V> extends MapBase<K, V> {
     }
   }
 
-  Map<KR, VR> cast<KR, VR>() {
-    Map<Object, Object> self = this;
-    return self is Map<KR, VR> ? self : Map.castFrom<K, V, KR, VR>(this);
-  }
+  Map<KR, VR> cast<KR, VR>() => Map.castFrom<K, V, KR, VR>(this);
 
-  Map<KR, VR> retype<KR, VR>() => Map.castFrom<K, V, KR, VR>(this);
+  @Deprecated("Use cast instead.")
+  Map<KR, VR> retype<KR, VR>() => cast<KR, VR>();
 
   Iterable<MapEntry<K, V>> get entries => _maps[0].entries;
 
diff --git a/pkg/compiler/lib/src/helpers/track_map.dart b/pkg/compiler/lib/src/helpers/track_map.dart
index 833a08a5701..0a87cf5fd63 100644
--- a/pkg/compiler/lib/src/helpers/track_map.dart
+++ b/pkg/compiler/lib/src/helpers/track_map.dart
@@ -99,7 +99,8 @@ class TrackMap<K, V> implements Map<K, V> {
 
   Map<KR, VR> cast<KR, VR>() => _map.cast<KR, VR>();
 
-  Map<KR, VR> retype<KR, VR>() => _map.retype<KR, VR>();
+  @Deprecated("Use cast instead.")
+  Map<KR, VR> retype<KR, VR>() => cast<KR, VR>();
 
   Iterable<MapEntry<K, V>> get entries => _map.entries;
 
diff --git a/pkg/compiler/lib/src/util/emptyset.dart b/pkg/compiler/lib/src/util/emptyset.dart
index d37b0c422b2..1fa3dbaddb1 100644
--- a/pkg/compiler/lib/src/util/emptyset.dart
+++ b/pkg/compiler/lib/src/util/emptyset.dart
@@ -9,12 +9,10 @@ import 'dart:collection' show IterableBase;
 class ImmutableEmptySet<E> extends IterableBase<E> implements Set<E> {
   const ImmutableEmptySet();
 
-  Set<R> cast<R>() {
-    Set<Object> self = this;
-    return self is Set<R> ? self : this.retype<R>();
-  }
+  Set<R> cast<R>() => new ImmutableEmptySet<R>();
 
-  Set<R> retype<R>() => new ImmutableEmptySet<R>();
+  @Deprecated("Use cast instead.")
+  Set<R> retype<R>() => cast<R>();
 
   get iterator => const _EmptySetIterator();
   int get length => 0;
diff --git a/pkg/compiler/lib/src/util/setlet.dart b/pkg/compiler/lib/src/util/setlet.dart
index 27e7a863b81..08195f051e5 100644
--- a/pkg/compiler/lib/src/util/setlet.dart
+++ b/pkg/compiler/lib/src/util/setlet.dart
@@ -29,7 +29,10 @@ class Setlet<E> extends SetBase<E> {
 
   static Set<R> _newSet<R>() => new Setlet<R>();
 
-  Set<R> retype<R>() => Set.castFrom<E, R>(this, newSet: _newSet);
+  Set<R> cast<R>() => Set.castFrom<E, R>(this, newSet: _newSet);
+
+  @Deprecated("Use cast instead.")
+  Set<R> retype<R>() => cast<R>();
 
   Iterator<E> get iterator {
     if (_extra == null) {
diff --git a/pkg/dev_compiler/tool/input_sdk/private/js_array.dart b/pkg/dev_compiler/tool/input_sdk/private/js_array.dart
index abcf157db90..3cac8a5beb5 100644
--- a/pkg/dev_compiler/tool/input_sdk/private/js_array.dart
+++ b/pkg/dev_compiler/tool/input_sdk/private/js_array.dart
@@ -66,12 +66,10 @@ class JSArray<E> implements List<E>, JSIndexable<E> {
     }
   }
 
-  List<R> cast<R>() {
-    List<Object> self = this;
-    return self is List<R> ? self : List.castFrom<E, R>(this);
-  }
+  List<R> cast<R>() => List.castFrom<E, R>(this);
 
-  List<R> retype<R>() => List.castFrom<E, R>(this);
+  @Deprecated("Use cast instead.")
+  List<R> retype<R>() => cast<R>();
 
   void add(E value) {
     checkGrowable('add');
diff --git a/runtime/lib/compact_hash.dart b/runtime/lib/compact_hash.dart
index 82bc53209a1..fb3d938b0e6 100644
--- a/runtime/lib/compact_hash.dart
+++ b/runtime/lib/compact_hash.dart
@@ -460,12 +460,10 @@ class _CompactLinkedHashSet<E> extends _HashFieldBase
 
   static Set<R> _newEmpty<R>() => new _CompactLinkedHashSet<R>();
 
-  Set<R> cast<R>() {
-    Set<Object> self = this;
-    return self is Set<R> ? self : Set.castFrom<E, R>(this, newSet: _newEmpty);
-  }
+  Set<R> cast<R>() => Set.castFrom<E, R>(this, newSet: _newEmpty);
 
-  Set<R> retype<R>() => Set.castFrom<E, R>(this, newSet: _newEmpty);
+  @Deprecated("Use cast instead.")
+  Set<R> retype<R>() => cast<R>();
 
   int get length => _usedData - _deletedKeys;
 
@@ -623,12 +621,10 @@ class _CompactLinkedIdentityHashSet<E> extends _CompactLinkedHashSet<E>
 
   static Set<R> _newEmpty<R>() => new _CompactLinkedIdentityHashSet<R>();
 
-  Set<R> cast<R>() {
-    Set<Object> self = this;
-    return self is Set<R> ? self : Set.castFrom<E, R>(this, newSet: _newEmpty);
-  }
+  Set<R> cast<R>() => Set.castFrom<E, R>(this, newSet: _newEmpty);
 
-  Set<R> retype<R>() => Set.castFrom<E, R>(this, newSet: _newEmpty);
+  @Deprecated("Use cast instead.")
+  Set<R> retype<R>() => cast<R>();
 }
 
 class _CompactLinkedCustomHashSet<E> extends _CompactLinkedHashSet<E> {
@@ -646,12 +642,10 @@ class _CompactLinkedCustomHashSet<E> extends _CompactLinkedHashSet<E> {
   _CompactLinkedCustomHashSet(this._equality, this._hasher, validKey)
       : _validKey = (validKey != null) ? validKey : new _TypeTest<E>().test;
 
-  Set<R> cast<R>() {
-    Set<Object> self = this;
-    return self is Set<R> ? self : Set.castFrom<E, R>(this);
-  }
+  Set<R> cast<R>() => Set.castFrom<E, R>(this);
 
-  Set<R> retype<R>() => Set.castFrom<E, R>(this);
+  @Deprecated("Use cast instead.")
+  Set<R> retype<R>() => cast<R>();
 
   Set<E> toSet() =>
       new _CompactLinkedCustomHashSet<E>(_equality, _hasher, _validKey)
diff --git a/runtime/lib/immutable_map.dart b/runtime/lib/immutable_map.dart
index 0417d71218d..2057a574eb6 100644
--- a/runtime/lib/immutable_map.dart
+++ b/runtime/lib/immutable_map.dart
@@ -13,12 +13,10 @@ class _ImmutableMap<K, V> implements Map<K, V> {
   const _ImmutableMap._create(_ImmutableList keyValuePairs)
       : _kvPairs = keyValuePairs;
 
-  Map<K2, V2> cast<K2, V2>() {
-    Map<Object, Object> self = this;
-    return (self is Map<K2, V2>) ? self : this.retype<K2, V2>();
-  }
+  Map<K2, V2> cast<K2, V2>() => Map.castFrom<K, V, K2, V2>(this);
 
-  Map<K2, V2> retype<K2, V2>() => Map.castFrom<K, V, K2, V2>(this);
+  @Deprecated("Use cast instead.")
+  Map<K2, V2> retype<K2, V2>() => cast<K2, V2>();
 
   V operator [](Object key) {
     // To preserve the key-value order of the map literal, the keys are
diff --git a/runtime/lib/typed_data_patch.dart b/runtime/lib/typed_data_patch.dart
index 383bfcda35a..b868a2d2521 100644
--- a/runtime/lib/typed_data_patch.dart
+++ b/runtime/lib/typed_data_patch.dart
@@ -123,12 +123,10 @@ abstract class _IntListMixin implements List<int> {
   Iterable<int> followedBy(Iterable<int> other) =>
       new FollowedByIterable<int>.firstEfficient(this, other);
 
-  List<R> cast<R>() {
-    List<Object> self = this;
-    return self is List<R> ? self : List.castFrom<int, R>(this);
-  }
+  List<R> cast<R>() => List.castFrom<int, R>(this);
 
-  List<R> retype<R>() => List.castFrom<int, R>(this);
+  @Deprecated("Use cast instead.")
+  List<R> retype<R>() => cast<R>();
 
   void set first(int value) {
     if (this.length == 0) throw new RangeError.index(0, this);
@@ -486,12 +484,10 @@ abstract class _DoubleListMixin implements List<double> {
   Iterable<double> followedBy(Iterable<double> other) =>
       new FollowedByIterable<double>.firstEfficient(this, other);
 
-  List<R> cast<R>() {
-    List<Object> self = this;
-    return self is List<R> ? self : List.castFrom<double, R>(this);
-  }
+  List<R> cast<R>() => List.castFrom<double, R>(this);
 
-  List<R> retype<R>() => List.castFrom<double, R>(this);
+  @Deprecated("Use cast instead.")
+  List<R> retype<R>() => cast<R>();
 
   void set first(double value) {
     if (this.length == 0) throw new RangeError.index(0, this);
@@ -852,12 +848,10 @@ abstract class _Float32x4ListMixin implements List<Float32x4> {
   Iterable<Float32x4> followedBy(Iterable<Float32x4> other) =>
       new FollowedByIterable<Float32x4>.firstEfficient(this, other);
 
-  List<R> cast<R>() {
-    List<Object> self = this;
-    return self is List<R> ? self : List.castFrom<Float32x4, R>(this);
-  }
+  List<R> cast<R>() => List.castFrom<Float32x4, R>(this);
 
-  List<R> retype<R>() => List.castFrom<Float32x4, R>(this);
+  @Deprecated("Use cast instead.")
+  List<R> retype<R>() => cast<R>();
 
   void set first(Float32x4 value) {
     if (this.length == 0) throw new RangeError.index(0, this);
@@ -1222,12 +1216,10 @@ abstract class _Int32x4ListMixin implements List<Int32x4> {
   Iterable<Int32x4> followedBy(Iterable<Int32x4> other) =>
       new FollowedByIterable<Int32x4>.firstEfficient(this, other);
 
-  List<R> cast<R>() {
-    List<Object> self = this;
-    return self is List<R> ? self : List.castFrom<Int32x4, R>(this);
-  }
+  List<R> cast<R>() => List.castFrom<Int32x4, R>(this);
 
-  List<R> retype<R>() => List.castFrom<Int32x4, R>(this);
+  @Deprecated("Use cast instead.")
+  List<R> retype<R>() => cast<R>();
 
   void set first(Int32x4 value) {
     if (this.length == 0) throw new RangeError.index(0, this);
@@ -1591,12 +1583,10 @@ abstract class _Float64x2ListMixin implements List<Float64x2> {
   Iterable<Float64x2> followedBy(Iterable<Float64x2> other) =>
       new FollowedByIterable<Float64x2>.firstEfficient(this, other);
 
-  List<R> cast<R>() {
-    List<Object> self = this;
-    return self is List<R> ? self : List.castFrom<Float64x2, R>(this);
-  }
+  List<R> cast<R>() => List.castFrom<Float64x2, R>(this);
 
-  List<R> retype<R>() => List.castFrom<Float64x2, R>(this);
+  @Deprecated("Use cast instead.")
+  List<R> retype<R>() => cast<R>();
 
   void set first(Float64x2 value) {
     if (this.length == 0) throw new RangeError.index(0, this);
diff --git a/samples-dev/swarm/swarm_ui_lib/observable/observable.dart b/samples-dev/swarm/swarm_ui_lib/observable/observable.dart
index e9d32f8c027..4ae4097ef50 100644
--- a/samples-dev/swarm/swarm_ui_lib/observable/observable.dart
+++ b/samples-dev/swarm/swarm_ui_lib/observable/observable.dart
@@ -148,7 +148,8 @@ class ObservableList<T> extends AbstractObservable
 
   List<R> cast<R>() => _internal.cast<R>();
 
-  List<R> retype<R>() => _internal.retype<R>();
+  @Deprecated("Use cast instead.")
+  List<R> retype<R>() => cast<R>();
 
   Iterable<R> whereType<R>() => _internal.whereType<R>();
 
diff --git a/sdk/lib/_http/http_session.dart b/sdk/lib/_http/http_session.dart
index 1e1ff5e3ed5..baca21b8bee 100644
--- a/sdk/lib/_http/http_session.dart
+++ b/sdk/lib/_http/http_session.dart
@@ -79,7 +79,8 @@ class _HttpSession implements HttpSession {
 
   Map<K, V> cast<K, V>() => _data.cast<K, V>();
 
-  Map<K, V> retype<K, V>() => _data.retype<K, V>();
+  @Deprecated("Use cast instead.")
+  Map<K, V> retype<K, V>() => cast<K, V>();
 
   update(key, update(value), {ifAbsent()}) =>
       _data.update(key, update, ifAbsent: ifAbsent);
diff --git a/sdk/lib/_internal/js_runtime/lib/constant_map.dart b/sdk/lib/_internal/js_runtime/lib/constant_map.dart
index cf0285a31b6..9f571b915e4 100644
--- a/sdk/lib/_internal/js_runtime/lib/constant_map.dart
+++ b/sdk/lib/_internal/js_runtime/lib/constant_map.dart
@@ -47,12 +47,10 @@ abstract class ConstantMap<K, V> implements Map<K, V> {
 
   const ConstantMap._();
 
-  Map<RK, RV> cast<RK, RV>() {
-    Map<Object, Object> self = this;
-    return self is Map<RK, RV> ? self : Map.castFrom<K, V, RK, RV>(this);
-  }
+  Map<RK, RV> cast<RK, RV>() => Map.castFrom<K, V, RK, RV>(this);
 
-  Map<RK, RV> retype<RK, RV>() => Map.castFrom<K, V, RK, RV>(this);
+  @Deprecated("Use cast instead.")
+  Map<RK, RV> retype<RK, RV>() => cast<RK, RV>();
 
   bool get isEmpty => length == 0;
 
diff --git a/sdk/lib/_internal/js_runtime/lib/js_array.dart b/sdk/lib/_internal/js_runtime/lib/js_array.dart
index 04e8f49cd16..df030037e40 100644
--- a/sdk/lib/_internal/js_runtime/lib/js_array.dart
+++ b/sdk/lib/_internal/js_runtime/lib/js_array.dart
@@ -119,12 +119,10 @@ class JSArray<E> extends Interceptor implements List<E>, JSIndexable {
     }
   }
 
-  List<R> cast<R>() {
-    List<Object> self = this;
-    return self is List<R> ? self : List.castFrom<E, R>(this);
-  }
+  List<R> cast<R>() => List.castFrom<E, R>(this);
 
-  List<R> retype<R>() => List.castFrom<E, R>(this);
+  @Deprecated("Use cast instead.")
+  List<R> retype<R>() => cast<R>();
 
   void add(E value) {
     checkGrowable('add');
diff --git a/sdk/lib/async/stream.dart b/sdk/lib/async/stream.dart
index 4f9f8a96ef0..5df84c57550 100644
--- a/sdk/lib/async/stream.dart
+++ b/sdk/lib/async/stream.dart
@@ -932,25 +932,16 @@ abstract class Stream<T> {
     return future;
   }
 
-  /**
-   * Adapt this stream to be a `Stream<R>`.
-   *
-   * If this stream already has the desired type, its returned directly.
-   * Otherwise it is wrapped as a `Stream<R>` which checks at run-time that
-   * each data event emitted by this stream is also an instance of [R].
-   */
-  Stream<R> cast<R>() {
-    Stream<Object> self = this;
-    return self is Stream<R> ? self : retype<R>();
-  }
-
   /**
    * Adapt this stream to be a `Stream<R>`.
    *
    * This stream is wrapped as a `Stream<R>` which checks at run-time that
    * each data event emitted by this stream is also an instance of [R].
    */
-  Stream<R> retype<R>() => Stream.castFrom<T, R>(this);
+  Stream<R> cast<R>() => Stream.castFrom<T, R>(this);
+
+  @Deprecated("Use cast instead.")
+  Stream<R> retype<R>() => cast<R>();
 
   /**
    * Collects all elements of this stream in a [List].
@@ -2020,15 +2011,6 @@ abstract class StreamTransformer<S, T> {
    */
   Stream<T> bind(Stream<S> stream);
 
-  /**
-   * Provides a `StreamTransformer<RS, RT>` view of this stream transformer.
-   *
-   * If this transformer already has the desired type, or a subtype,
-   * it is returned directly,
-   * otherwise returns the result of `retype<RS, RT>()`.
-   */
-  StreamTransformer<RS, RT> cast<RS, RT>();
-
   /**
    * Provides a `StreamTrasformer<RS, RT>` view of this stream transformer.
    *
@@ -2037,6 +2019,9 @@ abstract class StreamTransformer<S, T> {
    * and it will check that all data events produced by this transformer
    * are acually instances of [RT].
    */
+  StreamTransformer<RS, RT> cast<RS, RT>();
+
+  @Deprecated("Use cast instead.")
   StreamTransformer<RS, RT> retype<RS, RT>();
 }
 
@@ -2048,13 +2033,11 @@ abstract class StreamTransformer<S, T> {
 abstract class StreamTransformerBase<S, T> implements StreamTransformer<S, T> {
   const StreamTransformerBase();
 
-  StreamTransformer<RS, RT> cast<RS, RT>() {
-    StreamTransformer<Object, Object> self = this;
-    return self is StreamTransformer<RS, RT> ? self : retype<RS, RT>();
-  }
-
-  StreamTransformer<RS, RT> retype<RS, RT>() =>
+  StreamTransformer<RS, RT> cast<RS, RT>() =>
       StreamTransformer.castFrom<S, T, RS, RT>(this);
+
+  @Deprecated("Use cast instead.")
+  StreamTransformer<RS, RT> retype<RS, RT>() => cast<RS, RT>();
 }
 
 /**
diff --git a/sdk/lib/collection/collections.dart b/sdk/lib/collection/collections.dart
index 743e27ab962..f20b5ce937f 100644
--- a/sdk/lib/collection/collections.dart
+++ b/sdk/lib/collection/collections.dart
@@ -21,13 +21,10 @@ class UnmodifiableListView<E> extends UnmodifiableListBase<E> {
    */
   UnmodifiableListView(Iterable<E> source) : _source = source;
 
-  List<R> cast<R>() {
-    List<Object> self = this;
-    if (self is List<R>) return self;
-    return new UnmodifiableListView<R>(_source.cast<R>());
-  }
+  List<R> cast<R>() => new UnmodifiableListView(_source.cast<R>());
 
-  List<R> retype<R>() => new UnmodifiableListView(_source.retype<R>());
+  @Deprecated("Use cast instead.")
+  List<R> retype<R>() => cast<R>();
 
   int get length => _source.length;
 
diff --git a/sdk/lib/collection/hash_set.dart b/sdk/lib/collection/hash_set.dart
index b652da3421d..b75dc446812 100644
--- a/sdk/lib/collection/hash_set.dart
+++ b/sdk/lib/collection/hash_set.dart
@@ -14,14 +14,10 @@ abstract class _HashSetBase<E> extends SetBase<E> {
 
   Set<R> _newSimilarSet<R>();
 
-  Set<R> cast<R>() {
-    Set<Object> self = this;
-    return self is Set<R>
-        ? self
-        : Set.castFrom<E, R>(this, newSet: _newSimilarSet);
-  }
+  Set<R> cast<R>() => Set.castFrom<E, R>(this, newSet: _newSimilarSet);
 
-  Set<R> retype<R>() => Set.castFrom<E, R>(this, newSet: _newSimilarSet);
+  @Deprecated("Use cast instead.")
+  Set<R> retype<R>() => cast<R>();
 
   Set<E> difference(Set<Object> other) {
     Set<E> result = _newSet();
diff --git a/sdk/lib/collection/iterable.dart b/sdk/lib/collection/iterable.dart
index 6b88ff93bd5..fe1873a672d 100644
--- a/sdk/lib/collection/iterable.dart
+++ b/sdk/lib/collection/iterable.dart
@@ -15,12 +15,10 @@ abstract class IterableMixin<E> implements Iterable<E> {
   // - SetMixin
   // If changing a method here, also change the other copies.
 
-  Iterable<R> cast<R>() {
-    Iterable<Object> self = this;
-    return self is Iterable<R> ? self : Iterable.castFrom<E, R>(this);
-  }
+  Iterable<R> cast<R>() => Iterable.castFrom<E, R>(this);
 
-  Iterable<R> retype<R>() => Iterable.castFrom<E, R>(this);
+  @Deprecated("Use cast instead.")
+  Iterable<R> retype<R>() => cast<R>();
 
   Iterable<T> map<T>(T f(E element)) => new MappedIterable<E, T>(this, f);
 
diff --git a/sdk/lib/collection/list.dart b/sdk/lib/collection/list.dart
index 4ced94b326d..fb430a783a2 100644
--- a/sdk/lib/collection/list.dart
+++ b/sdk/lib/collection/list.dart
@@ -329,12 +329,10 @@ abstract class ListMixin<E> implements List<E> {
     this.length = 0;
   }
 
-  List<R> cast<R>() {
-    List<Object> self = this;
-    return self is List<R> ? self : List.castFrom<E, R>(this);
-  }
+  List<R> cast<R>() => List.castFrom<E, R>(this);
 
-  List<R> retype<R>() => List.castFrom<E, R>(this);
+  @Deprecated("Use cast instead.")
+  List<R> retype<R>() => cast<R>();
 
   E removeLast() {
     if (length == 0) {
diff --git a/sdk/lib/collection/maps.dart b/sdk/lib/collection/maps.dart
index bdd775aab96..5bc178d0a46 100644
--- a/sdk/lib/collection/maps.dart
+++ b/sdk/lib/collection/maps.dart
@@ -118,12 +118,10 @@ abstract class MapMixin<K, V> implements Map<K, V> {
   // It should clear the map even if some keys are not equal to themselves.
   void clear();
 
-  Map<RK, RV> cast<RK, RV>() {
-    Map<Object, Object> self = this;
-    return self is Map<RK, RV> ? self : Map.castFrom<K, V, RK, RV>(this);
-  }
+  Map<RK, RV> cast<RK, RV>() => Map.castFrom<K, V, RK, RV>(this);
 
-  Map<RK, RV> retype<RK, RV>() => Map.castFrom<K, V, RK, RV>(this);
+  @Deprecated("Use cast instead.")
+  Map<RK, RV> retype<RK, RV>() => cast<RK, RV>();
 
   void forEach(void action(K key, V value)) {
     for (K key in keys) {
@@ -318,7 +316,8 @@ class MapView<K, V> implements Map<K, V> {
 
   Map<RK, RV> cast<RK, RV>() => _map.cast<RK, RV>();
 
-  Map<RK, RV> retype<RK, RV>() => _map.retype<RK, RV>();
+  @Deprecated("Use cast instead.")
+  Map<RK, RV> retype<RK, RV>() => cast<RK, RV>();
 
   V operator [](Object key) => _map[key];
   void operator []=(K key, V value) {
@@ -380,12 +379,9 @@ class UnmodifiableMapView<K, V> extends MapView<K, V>
     with _UnmodifiableMapMixin<K, V> {
   UnmodifiableMapView(Map<K, V> map) : super(map);
 
-  Map<RK, RV> cast<RK, RV>() {
-    Map<Object, Object> self = this;
-    if (self is Map<RK, RV>) return self;
-    return new UnmodifiableMapView<RK, RV>(_map.cast<RK, RV>());
-  }
+  Map<RK, RV> cast<RK, RV>() =>
+      new UnmodifiableMapView<RK, RV>(_map.cast<RK, RV>());
 
-  Map<RK, RV> retype<RK, RV>() =>
-      new UnmodifiableMapView<RK, RV>(_map.retype<RK, RV>());
+  @Deprecated("Use cast instead.")
+  Map<RK, RV> retype<RK, RV>() => cast<RK, RV>();
 }
diff --git a/sdk/lib/collection/queue.dart b/sdk/lib/collection/queue.dart
index 48136e642be..2242fb272e0 100644
--- a/sdk/lib/collection/queue.dart
+++ b/sdk/lib/collection/queue.dart
@@ -66,9 +66,7 @@ abstract class Queue<E> implements EfficientLengthIterable<E> {
       new CastQueue<S, T>(source);
 
   /**
-   * Provides a view of this queue as a queue of [R] instances.
-   *
-   * If this queue is already a `Queue<R>`, it is returned unchanged.
+   * Provides a view of this queue as a queue of [R] instances, if necessary.
    *
    * If this queue contains only instances of [R], all read operations
    * will work correctly. If any operation tries to access an element
@@ -81,18 +79,7 @@ abstract class Queue<E> implements EfficientLengthIterable<E> {
    */
   Queue<R> cast<R>();
 
-  /**
-   * Provides a view of this queue as a queue of [R] instances, if necessary.
-   *
-   * If this queue contains only instances of [R], all read operations
-   * will work correctly. If any operation tries to access an element
-   * that is not an instance of [R], the access will throw instead.
-   *
-   * Elements added to the queue (e.g., by using [addFirst] or [addAll])
-   * must be instance of [R] to be valid arguments to the adding function,
-   * and they must be instances of [E] as well to be accepted by
-   * this queue as well.
-   */
+  @Deprecated("Use cast instead.")
   Queue<R> retype<R>();
 
   /**
@@ -356,12 +343,10 @@ class DoubleLinkedQueue<E> extends Iterable<E> implements Queue<E> {
   factory DoubleLinkedQueue.of(Iterable<E> elements) =>
       new DoubleLinkedQueue<E>()..addAll(elements);
 
-  Queue<R> cast<R>() {
-    Queue<Object> self = this;
-    return self is Queue<R> ? self : Queue.castFrom<E, R>(this);
-  }
+  Queue<R> cast<R>() => Queue.castFrom<E, R>(this);
 
-  Queue<R> retype<R>() => Queue.castFrom<E, R>(this);
+  @Deprecated("Use cast instead.")
+  Queue<R> retype<R>() => cast<R>();
 
   int get length => _elementCount;
 
@@ -657,12 +642,10 @@ class ListQueue<E> extends ListIterable<E> implements Queue<E> {
 
   // Iterable interface.
 
-  Queue<R> cast<R>() {
-    Queue<Object> self = this;
-    return self is Queue<R> ? self : this.retype<R>();
-  }
+  Queue<R> cast<R>() => Queue.castFrom<E, R>(this);
 
-  Queue<R> retype<R>() => Queue.castFrom<E, R>(this);
+  @Deprecated("Use cast instead.")
+  Queue<R> retype<R>() => cast<R>();
 
   Iterator<E> get iterator => new _ListQueueIterator<E>(this);
 
diff --git a/sdk/lib/collection/set.dart b/sdk/lib/collection/set.dart
index 377d574baee..86e832910fe 100644
--- a/sdk/lib/collection/set.dart
+++ b/sdk/lib/collection/set.dart
@@ -23,10 +23,6 @@ part of dart.collection;
  * Implementations of `Set` using this mixin should consider also implementing
  * `clear` in constant time. The default implementation works by removing every
  * element.
- *
- * The [cast] implementation uses [retype] to do the actual cast, so if
- * the cast operation wants to pass a custom `newSet` to [Set.castFrom],
- * it only needs to override [retype].
  */
 abstract class SetMixin<E> implements Set<E> {
   // This class reimplements all of [IterableMixin].
@@ -51,12 +47,10 @@ abstract class SetMixin<E> implements Set<E> {
 
   bool get isNotEmpty => length != 0;
 
-  Set<R> cast<R>() {
-    Set<Object> self = this;
-    return self is Set<R> ? self : this.retype<R>();
-  }
+  Set<R> cast<R>() => Set.castFrom<E, R>(this);
 
-  Set<R> retype<R>() => Set.castFrom<E, R>(this);
+  @Deprecated("Use cast instead.")
+  Set<R> retype<R>() => cast<R>();
 
   Iterable<E> followedBy(Iterable<E> other) =>
       new FollowedByIterable<E>.firstEfficient(this, other);
diff --git a/sdk/lib/collection/splay_tree.dart b/sdk/lib/collection/splay_tree.dart
index fad3ce809a2..dce7dc5e185 100644
--- a/sdk/lib/collection/splay_tree.dart
+++ b/sdk/lib/collection/splay_tree.dart
@@ -765,12 +765,10 @@ class SplayTreeSet<E> extends _SplayTree<E, _SplayTreeNode<E>>
   Set<T> _newSet<T>() =>
       new SplayTreeSet<T>((T a, T b) => _comparator(a as E, b as E), _validKey);
 
-  Set<R> cast<R>() {
-    Set<Object> self = this;
-    return self is Set<R> ? self : Set.castFrom<E, R>(this, newSet: _newSet);
-  }
+  Set<R> cast<R>() => Set.castFrom<E, R>(this, newSet: _newSet);
 
-  Set<R> retype<R>() => Set.castFrom<E, R>(this, newSet: _newSet);
+  @Deprecated("Use cast instead.")
+  Set<R> retype<R>() => cast<R>();
 
   int _compare(E e1, E e2) => _comparator(e1, e2);
 
diff --git a/sdk/lib/convert/converter.dart b/sdk/lib/convert/converter.dart
index 01d61865727..3fdcb4c7b11 100644
--- a/sdk/lib/convert/converter.dart
+++ b/sdk/lib/convert/converter.dart
@@ -56,18 +56,6 @@ abstract class Converter<S, T> extends StreamTransformerBase<S, T> {
         stream, (EventSink sink) => new _ConverterStreamEventSink(this, sink));
   }
 
-  /**
-   * Provides a `Converter<RS, RT>` view of this stream transformer.
-   *
-   * If this transformer already has the desired type, or a subtype,
-   * it is returned directly,
-   * otherwise returns the result of `retype<RS, RT>()`.
-   */
-  Converter<RS, RT> cast<RS, RT>() {
-    Converter<Object, Object> self = this;
-    return self is Converter<RS, RT> ? self : retype<RS, RT>();
-  }
-
   /**
    * Provides a `Converter<RS, RT>` view of this stream transformer.
    *
@@ -76,7 +64,10 @@ abstract class Converter<S, T> extends StreamTransformerBase<S, T> {
    * and it will check that all conversion output produced by this converter
    * are acually instances of [RT].
    */
-  Converter<RS, RT> retype<RS, RT>() => Converter.castFrom<S, T, RS, RT>(this);
+  Converter<RS, RT> cast<RS, RT>() => Converter.castFrom<S, T, RS, RT>(this);
+
+  @Deprecated("Use cast instead.")
+  Converter<RS, RT> retype<RS, RT>() => cast<RS, RT>();
 }
 
 /**
diff --git a/sdk/lib/core/iterable.dart b/sdk/lib/core/iterable.dart
index 218781211a6..99361f71be5 100644
--- a/sdk/lib/core/iterable.dart
+++ b/sdk/lib/core/iterable.dart
@@ -153,20 +153,6 @@ abstract class Iterable<E> {
    */
   Iterator<E> get iterator;
 
-  /**
-   * Makes this iterable useful as an `Iterable<R>`, if necessary.
-   *
-   * Like [retype] except that this iterable is returned as-is
-   * if it is already an `Iterable<R>`.
-   *
-   * It means that `someIterable.cast<Object>().toList()` is not guaranteed
-   * to return precisely a `List<Object>`, but it may return a subtype.
-   */
-  Iterable<R> cast<R>() {
-    Iterable<Object> self = this;
-    return self is Iterable<R> ? self : Iterable.castFrom<E, R>(this);
-  }
-
   /**
    * Provides a view of this iterable as an iterable of [R] instances.
    *
@@ -177,7 +163,10 @@ abstract class Iterable<E> {
    * When the returned iterable creates a new object that depends on
    * the type [R], e.g., from [toList], it will have exactly the type [R].
    */
-  Iterable<R> retype<R>() => Iterable.castFrom<E, R>(this);
+  Iterable<R> cast<R>() => Iterable.castFrom<E, R>(this);
+
+  @Deprecated("Use cast instead.")
+  Iterable<R> retype<R>() => cast<R>();
 
   /**
    * Returns the lazy concatentation of this iterable and [other].
diff --git a/sdk/lib/core/list.dart b/sdk/lib/core/list.dart
index 8df6ca5b3b6..bff5b31a403 100644
--- a/sdk/lib/core/list.dart
+++ b/sdk/lib/core/list.dart
@@ -253,22 +253,6 @@ abstract class List<E> implements EfficientLengthIterable<E> {
     }
   }
 
-  /**
-   * Returns a view of this list as a list of [R] instances, if necessary.
-   *
-   * If this list is already a `List<R>`, it is returned unchanged.
-   *
-   * If this list contains only instances of [R], all read operations
-   * will work correctly. If any operation tries to access an element
-   * that is not an instance of [R], the access will throw instead.
-   *
-   * Elements added to the list (e.g., by using [add] or [addAll])
-   * must be instance of [R] to be valid arguments to the adding function,
-   * and they must be instances of [E] as well to be accepted by
-   * this list as well.
-   */
-  List<R> cast<R>();
-
   /**
    * Returns a view of this list as a list of [R] instances.
    *
@@ -283,6 +267,9 @@ abstract class List<E> implements EfficientLengthIterable<E> {
    *
    * Typically implemented as `List.castFrom<E, R>(this)`.
    */
+  List<R> cast<R>();
+
+  @Deprecated("Use cast instead.")
   List<R> retype<R>();
 
   /**
diff --git a/sdk/lib/core/map.dart b/sdk/lib/core/map.dart
index 9009dff5b24..51fda37fb60 100644
--- a/sdk/lib/core/map.dart
+++ b/sdk/lib/core/map.dart
@@ -177,20 +177,6 @@ abstract class Map<K, V> {
   factory Map.fromEntries(Iterable<MapEntry<K, V>> entries) =>
       <K, V>{}..addEntries(entries);
 
-  /**
-   * Provides a view of this map as having [RK] keys and [RV] instances,
-   * if necessary.
-   *
-   * If this set contains only keys of type [RK] and values of type [RV],
-   * all read operations will work correctly.
-   * If any operation exposes a non-[RK] key or non-[RV] value,
-   * the operation will throw instead.
-   *
-   * Entries added to the map must be valid for both a `Map<K, V>` and a
-   * `Map<RK, RV>`.
-   */
-  Map<RK, RV> cast<RK, RV>();
-
   /**
    * Provides a view of this map as having [RK] keys and [RV] instances,
    * if necessary.
@@ -205,6 +191,9 @@ abstract class Map<K, V> {
    * Entries added to the map must be valid for both a `Map<K, V>` and a
    * `Map<RK, RV>`.
    */
+  Map<RK, RV> cast<RK, RV>();
+
+  @Deprecated("Use cast instead.")
   Map<RK, RV> retype<RK, RV>();
 
   /**
diff --git a/sdk/lib/core/set.dart b/sdk/lib/core/set.dart
index e7c36be6653..d85ae2b497d 100644
--- a/sdk/lib/core/set.dart
+++ b/sdk/lib/core/set.dart
@@ -114,9 +114,7 @@ abstract class Set<E> extends EfficientLengthIterable<E> {
       new CastSet<S, T>(source, newSet);
 
   /**
-   * Provides a view of this set as a set of [R] instances, if necessary.
-   *
-   * If this set is already a `Set<R>`, it is returned unchanged.
+   * Provides a view of this set as a set of [R] instances.
    *
    * If this set contains only instances of [R], all read operations
    * will work correctly. If any operation tries to access an element
@@ -129,18 +127,7 @@ abstract class Set<E> extends EfficientLengthIterable<E> {
    */
   Set<R> cast<R>();
 
-  /**
-   * Provides a view of this set as a set of [R] instances.
-   *
-   * If this set contains only instances of [R], all read operations
-   * will work correctly. If any operation tries to access an element
-   * that is not an instance of [R], the access will throw instead.
-   *
-   * Elements added to the set (e.g., by using [add] or [addAll])
-   * must be instance of [R] to be valid arguments to the adding function,
-   * and they must be instances of [E] as well to be accepted by
-   * this set as well.
-   */
+  @Deprecated("Use cast instead.")
   Set<R> retype<R>();
 
   /**
diff --git a/sdk/lib/html/dart2js/html_dart2js.dart b/sdk/lib/html/dart2js/html_dart2js.dart
index acf0390cd7f..1f622c48197 100644
--- a/sdk/lib/html/dart2js/html_dart2js.dart
+++ b/sdk/lib/html/dart2js/html_dart2js.dart
@@ -46414,12 +46414,10 @@ abstract class _AttributeMap extends MapBase<String, String> {
     });
   }
 
-  Map<K, V> cast<K, V>() {
-    Map<Object, Object> self = this;
-    return self is Map<K, V> ? self : Map.castFrom<String, String, K, V>(this);
-  }
+  Map<K, V> cast<K, V>() => Map.castFrom<String, String, K, V>(this);
 
-  Map<K, V> retype<K, V>() => Map.castFrom<String, String, K, V>(this);
+  @Deprecated("Use cast instead.")
+  Map<K, V> retype<K, V>() => cast<K, V>();
 
   bool containsValue(Object value) {
     for (var v in this.values) {
@@ -46581,12 +46579,10 @@ class _DataAttributeMap extends MapBase<String, String> {
     });
   }
 
-  Map<K, V> cast<K, V>() {
-    Map<Object, Object> self = this;
-    return self is Map<K, V> ? self : Map.castFrom<String, String, K, V>(this);
-  }
+  Map<K, V> cast<K, V>() => Map.castFrom<String, String, K, V>(this);
 
-  Map<K, V> retype<K, V>() => Map.castFrom<String, String, K, V>(this);
+  @Deprecated("Use cast instead.")
+  Map<K, V> retype<K, V>() => cast<K, V>();
 
   // TODO: Use lazy iterator when it is available on Map.
   bool containsValue(Object value) => values.any((v) => v == value);
diff --git a/sdk/lib/internal/async_cast.dart b/sdk/lib/internal/async_cast.dart
index 924ac53f4e1..eb59a7d08bd 100644
--- a/sdk/lib/internal/async_cast.dart
+++ b/sdk/lib/internal/async_cast.dart
@@ -18,12 +18,10 @@ class CastStream<S, T> extends Stream<T> {
       ..onData(onData);
   }
 
-  Stream<R> cast<R>() {
-    Stream<Object> self = this;
-    return self is Stream<R> ? self : this.retype<R>();
-  }
+  Stream<R> cast<R>() => new CastStream<S, R>(_source);
 
-  Stream<R> retype<R>() => new CastStream<S, R>(_source);
+  @Deprecated("Use cast instead.")
+  Stream<R> retype<R>() => cast<R>();
 }
 
 class CastStreamSubscription<S, T> implements StreamSubscription<T> {
@@ -63,11 +61,12 @@ class CastStreamTransformer<SS, ST, TS, TT>
   final StreamTransformer<SS, ST> _source;
   CastStreamTransformer(this._source);
 
-  // cast is inherited from StreamTransformerBase.
-
-  StreamTransformer<RS, RT> retype<RS, RT>() =>
+  StreamTransformer<RS, RT> cast<RS, RT>() =>
       new CastStreamTransformer<SS, ST, RS, RT>(_source);
 
+  @Deprecated("Use cast instead.")
+  StreamTransformer<RS, RT> retype<RS, RT>() => cast<RS, RT>();
+
   Stream<TT> bind(Stream<TS> stream) =>
       _source.bind(stream.cast<SS>()).cast<TT>();
 }
@@ -83,6 +82,9 @@ class CastConverter<SS, ST, TS, TT> extends Converter<TS, TT> {
   Stream<TT> bind(Stream<TS> stream) =>
       _source.bind(stream.cast<SS>()).cast<TT>();
 
-  Converter<RS, RT> retype<RS, RT>() =>
+  Converter<RS, RT> cast<RS, RT>() =>
       new CastConverter<SS, ST, RS, RT>(_source);
+
+  @Deprecated("Use cast instead.")
+  Converter<RS, RT> retype<RS, RT>() => cast<RS, RT>();
 }
diff --git a/sdk/lib/internal/cast.dart b/sdk/lib/internal/cast.dart
index 97652531ca1..c2a6ce4f985 100644
--- a/sdk/lib/internal/cast.dart
+++ b/sdk/lib/internal/cast.dart
@@ -188,13 +188,10 @@ class CastSet<S, T> extends _CastIterableBase<S, T> implements Set<T> {
 
   static Set<R> _defaultEmptySet<R>() => new Set<R>();
 
-  Set<R> cast<R>() {
-    Set<Object> self = this;
-    if (self is Set<R>) return self;
-    return this.retype<R>();
-  }
+  Set<R> cast<R>() => new CastSet<S, R>(_source, _emptySet);
 
-  Set<R> retype<R>() => new CastSet<S, R>(_source, _emptySet);
+  @Deprecated("Use cast instead.")
+  Set<R> retype<R>() => cast<R>();
 
   bool add(T value) => _source.add(value as S);
 
@@ -370,13 +367,10 @@ class CastQueue<S, T> extends _CastIterableBase<S, T>
     with _CastQueueMixin<S, T> {
   final Queue<S> _source;
   CastQueue(this._source);
-  Queue<R> cast<R>() {
-    Queue<Object> self = this;
-    if (self is Queue<R>) return self;
-    return retype<R>();
-  }
+  Queue<R> cast<R>() => new CastQueue<S, R>(_source);
 
-  Queue<R> retype<R>() => new CastQueue<S, R>(_source);
+  @Deprecated("Use cast instead.")
+  Queue<R> retype<R>() => cast<R>();
 }
 
 // TODO(lrn): Use when ListQueue implements List.
diff --git a/tests/corelib_2/growable_list_test.dart b/tests/corelib_2/growable_list_test.dart
index f6787ffde17..ebe04bc0116 100644
--- a/tests/corelib_2/growable_list_test.dart
+++ b/tests/corelib_2/growable_list_test.dart
@@ -37,7 +37,9 @@ class EfficientTestIterable extends TestIterableBase implements Set<int> {
   // Avoid warnings because we don't actually implement Set.
   noSuchMethod(i) => super.noSuchMethod(i);
   Set<R> cast<R>() => throw "not used by test";
-  Set<R> retype<R>() => throw "not used by test";
+
+  @Deprecated("Use cast instead.")
+  Set<R> retype<R>() => cast<R>();
 }
 
 class CallbackIterator implements Iterator<int> {
diff --git a/tools/dom/src/AttributeMap.dart b/tools/dom/src/AttributeMap.dart
index 85aef194108..a6e79f3be33 100644
--- a/tools/dom/src/AttributeMap.dart
+++ b/tools/dom/src/AttributeMap.dart
@@ -15,12 +15,10 @@ abstract class _AttributeMap extends MapBase<String, String> {
     });
   }
 
-  Map<K, V> cast<K, V>() {
-    Map<Object, Object> self = this;
-    return self is Map<K, V> ? self : Map.castFrom<String, String, K, V>(this);
-  }
+  Map<K, V> cast<K, V>() => Map.castFrom<String, String, K, V>(this);
 
-  Map<K, V> retype<K, V>() => Map.castFrom<String, String, K, V>(this);
+  @Deprecated("Use cast instead.")
+  Map<K, V> retype<K, V>() => cast<K, V>();
 
   bool containsValue(Object value) {
     for (var v in this.values) {
@@ -182,12 +180,10 @@ class _DataAttributeMap extends MapBase<String, String> {
     });
   }
 
-  Map<K, V> cast<K, V>() {
-    Map<Object, Object> self = this;
-    return self is Map<K, V> ? self : Map.castFrom<String, String, K, V>(this);
-  }
+  Map<K, V> cast<K, V>() => Map.castFrom<String, String, K, V>(this);
 
-  Map<K, V> retype<K, V>() => Map.castFrom<String, String, K, V>(this);
+  @Deprecated("Use cast instead.")
+  Map<K, V> retype<K, V>() => cast<K, V>();
 
   // TODO: Use lazy iterator when it is available on Map.
   bool containsValue(Object value) => values.any((v) => v == value);