Dartc was not raising an error if an interface declared constructors without a default clause

tests/isolate/src/TestFramework.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.
 
 #library("TestFramework");
 #import("dart:coreimpl");
 
 
 typedef void AsynchronousTestFunction(TestExpectation check);
 
@@ skipping 52 matching lines @@
     setUp();
     result.runGuarded(this, () {
       performTest();
       tearDown();
     });
   }
 
   void addToTestSuite(TestSuite suite) {
     suite.addTestCase(this);
   }
-
 }
 
 
 class TestResult {
 
   TestResult(this.runner) : errors = [], failures = [];
 
   void error(String message, TestCase testCase) {
     errors.add([message, testCase]);
   }
@@ skipping 97 matching lines @@
       throw "must pass Promise or Future to TestFramework.completes";
     }
     Completer completer = new Completer();
     future.then(runs1((value) {
       completer.complete(value);
     }));
     return completer.future;
   }
 
   Promise completesWithValue(Promise promise, var expected) {
-    Promise result = new TestPromise(this);
+    Promise promiseResult = new TestPromise(this);
     promise.then((value) {
       Expect.equals(expected, value);
-      result.complete(value);
+      promiseResult.complete(value);
     });
-    return result;
+    return promiseResult;
   }
 
   Function runs0(Function fn) {
     bool ran = false;  // We only check that the function is executed once.
     pendingCallbacks++;
     return () {
       if (!ran) pendingCallbacks--;
       ran = true;
       return result.runGuarded(testCase, () => fn());
     };
@@ skipping 83 matching lines @@
 
   void addCompleteHandler(void completeHandler(T result)) {
     super.addCompleteHandler(expect.runs1((T result) {
       completeHandler(result);
     }));
   }
 
   final TestExpectation expect;
 
 }