Fix analyzer warnings

examples/fitness/lib/main.dart

@@ -124,7 +124,7 @@ class FitnessApp extends App {
         name: '/settings',
         builder: (navigator, route) => new SettingsFragment(
           navigator: navigator,
-          userData: _userData as UserData,
+          userData: _userData,
           updater: settingsUpdater
         )
       ),

examples/fitness/lib/settings.dart

@@ -28,14 +28,6 @@ class SettingsFragment extends StatefulComponent {
     updater(backup: value ? BackupMode.enabled : BackupMode.disabled);
   }
 
-  void _goalWeightChanged(double value) {
-    assert(updater != null);
-    setState(() {
-      optimism = value ? StockMode.optimistic : StockMode.pessimistic;
-    });
-    sendUpdates();
-  }
-
   Widget buildToolBar() {
     return new ToolBar(
       left: new IconButton(

packages/unit/test/engine/document_child_mutations_test.dart

@@ -70,30 +70,18 @@ void main() {
 
   test("should throw when inserting multiple elements", () {
     doc.appendChild(doc.createElement("div"));
-    var oldChild = doc.appendChild(doc.createText(" text "));
+    doc.appendChild(doc.createText(" text "));
     expect(childElementCount(doc), equals(1));
-    var newChild = doc.createElement("div");
-    // expect(() {
-    //   doc.replaceChild(newChild, 0);
-    // }, throws);
-    // expect(() {
-    //   doc.insertBefore(newChild, oldChild);
-    // }, throws);
+    doc.createElement("div");
   });
 
   test("should throw when inserting multiple elements with a fragment", () {
-    var oldChild = doc.appendChild(doc.createElement("div"));
+    doc.appendChild(doc.createElement("div"));
     expect(childElementCount(doc), equals(1));
     var fragment = doc.createDocumentFragment();
     fragment.appendChild(doc.createText(" text "));
     fragment.appendChild(doc.createElement("div"));
     fragment.appendChild(doc.createElement("div"));
     fragment.appendChild(doc.createText(" "));
-    // expect(() {
-    //   doc.replaceChild(fragment, 0);
-    // }, throws);
-    // expect(() {
-    //   doc.insertBefore(fragment, oldChild);
-    // }, throws);
   });
 }