Use iterator, moveNext(), current.

tests/corelib/set_iterator_test.dart

 // Copyright (c) 2011, 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.
 
 class FixedHashCode {
   final int _hashCode;
   const FixedHashCode(this._hashCode);
   int get hashCode { return _hashCode; }
 }
 
 class SetIteratorTest {
   static testMain() {
     testSmallSet();
     testLargeSet();
     testEmptySet();
     testSetWithDeletedEntries();
     testBug5116829();
     testDifferentSizes();
     testDifferentHashCodes();
   }
 
   static void testThrows(Iterator<int> it) {
-    Expect.equals(false, it.hasNext);
-    var exception = null;
-    try {
-      it.next();
-    } on StateError catch (e) {
-      exception = e;
-    }
-    Expect.equals(true, exception != null);
+    Expect.isFalse(it.moveNext());
+    Expect.throws(() { it.current; }, (e) => e is StateError);
   }
 
   static int sum(int expected, Iterator<int> it) {
     int count = 0;
-    while (it.hasNext) {
-      count += it.next();
+    while (it.moveNext()) {
+      count += it.current;
     }
     Expect.equals(expected, count);
   }
 
   static void testSmallSet() {
     Set<int> set = new Set<int>();
     set.add(1);
     set.add(2);
     set.add(3);
 
-    Iterator<int> it = set.iterator();
-    Expect.equals(true, it.hasNext);
+    Iterator<int> it = set.iterator;
     sum(6, it);
     testThrows(it);
   }
 
   static void testLargeSet() {
     Set<int> set = new Set<int>();
     int count = 0;
     for (int i = 0; i < 100; i++) {
       count += i;
       set.add(i);
     }
-    Iterator<int> it = set.iterator();
-    Expect.equals(true, it.hasNext);
+    Iterator<int> it = set.iterator;
     sum(count, it);
     testThrows(it);
   }
 
   static void testEmptySet() {
     Set<int> set = new Set<int>();
-    Iterator<int> it = set.iterator();
-    Expect.equals(false, it.hasNext);
+    Iterator<int> it = set.iterator;
     sum(0, it);
     testThrows(it);
   }
 
   static void testSetWithDeletedEntries() {
     Set<int> set = new Set<int>();
     for (int i = 0; i < 100; i++) {
       set.add(i);
     }
     for (int i = 0; i < 100; i++) {
       set.remove(i);
     }
-    Iterator<int> it = set.iterator();
-    Expect.equals(false, it.hasNext);
+    Iterator<int> it = set.iterator;
+    Expect.isFalse(it.moveNext());
+    it = set.iterator;
     sum(0, it);
     testThrows(it);
 
     int count = 0;
     for (int i = 0; i < 100; i++) {
       set.add(i);
       if (i % 2 == 0) set.remove(i);
       else count += i;
     }
-    it = set.iterator();
-    Expect.equals(true, it.hasNext);
+    it = set.iterator;
     sum(count, it);
     testThrows(it);
   }
 
   static void testBug5116829() {
     // During iteration we skipped slot 0 of the hashset's key list. "A" was
     // hashed to slot 0 and therefore triggered the bug.
     Set<String> mystrs = new Set<String>();
     mystrs.add("A");
     int seen = 0;
@@ skipping 35 matching lines @@
         Expect.equals(true, identical(x, element));
       }
       Expect.equals(true, foundIt);
     }
   }
 }
 
 main() {
   SetIteratorTest.testMain();
 }