a === b -> identical(a, b)

sdk/lib/core/queue.dart

Index: sdk/lib/core/queue.dart
diff --git a/sdk/lib/core/queue.dart b/sdk/lib/core/queue.dart
index bf1e49c2113bbc97e3066b5a9e98891c697aee05..e6e997fb9bb110761b6d77222969c03c39c4af23 100644
--- a/sdk/lib/core/queue.dart
+++ b/sdk/lib/core/queue.dart
@@ -234,7 +234,7 @@ class DoubleLinkedQueue<E> implements Queue<E> {
   }
 
   bool get isEmpty {
-    return (_sentinel._next === _sentinel);
+    return (identical(_sentinel._next, _sentinel));
   }
 
   void clear() {
@@ -244,7 +244,7 @@ class DoubleLinkedQueue<E> implements Queue<E> {
 
   void forEach(void f(E element)) {
     DoubleLinkedQueueEntry<E> entry = _sentinel._next;
-    while (entry !== _sentinel) {
+    while (!identical(entry, _sentinel)) {
       DoubleLinkedQueueEntry<E> nextEntry = entry._next;
       f(entry._element);
       entry = nextEntry;
@@ -253,7 +253,7 @@ class DoubleLinkedQueue<E> implements Queue<E> {
 
   void forEachEntry(void f(DoubleLinkedQueueEntry<E> element)) {
     DoubleLinkedQueueEntry<E> entry = _sentinel._next;
-    while (entry !== _sentinel) {
+    while (!identical(entry, _sentinel)) {
       DoubleLinkedQueueEntry<E> nextEntry = entry._next;
       f(entry);
       entry = nextEntry;
@@ -262,7 +262,7 @@ class DoubleLinkedQueue<E> implements Queue<E> {
 
   bool every(bool f(E element)) {
     DoubleLinkedQueueEntry<E> entry = _sentinel._next;
-    while (entry !== _sentinel) {
+    while (!identical(entry, _sentinel)) {
       DoubleLinkedQueueEntry<E> nextEntry = entry._next;
       if (!f(entry._element)) return false;
       entry = nextEntry;
@@ -272,7 +272,7 @@ class DoubleLinkedQueue<E> implements Queue<E> {
 
   bool some(bool f(E element)) {
     DoubleLinkedQueueEntry<E> entry = _sentinel._next;
-    while (entry !== _sentinel) {
+    while (!identical(entry, _sentinel)) {
       DoubleLinkedQueueEntry<E> nextEntry = entry._next;
       if (f(entry._element)) return true;
       entry = nextEntry;
@@ -283,7 +283,7 @@ class DoubleLinkedQueue<E> implements Queue<E> {
   Queue map(f(E element)) {
     Queue other = new Queue();
     DoubleLinkedQueueEntry<E> entry = _sentinel._next;
-    while (entry !== _sentinel) {
+    while (!identical(entry, _sentinel)) {
       DoubleLinkedQueueEntry<E> nextEntry = entry._next;
       other.addLast(f(entry._element));
       entry = nextEntry;
@@ -299,7 +299,7 @@ class DoubleLinkedQueue<E> implements Queue<E> {
   Queue<E> filter(bool f(E element)) {
     Queue<E> other = new Queue<E>();
     DoubleLinkedQueueEntry<E> entry = _sentinel._next;
-    while (entry !== _sentinel) {
+    while (!identical(entry, _sentinel)) {
       DoubleLinkedQueueEntry<E> nextEntry = entry._next;
       if (f(entry._element)) other.addLast(entry._element);
       entry = nextEntry;
@@ -325,7 +325,7 @@ class _DoubleLinkedQueueIterator<E> implements Iterator<E> {
   }
 
   bool get hasNext {
-    return _currentEntry._next !== _sentinel;
+    return !identical(_currentEntry._next, _sentinel);
   }
 
   E next() {