diff --git a/sdk/lib/rendering/box.dart b/sdk/lib/rendering/box.dart
index bf800c38b5e9fdb31708e143990a70df595aa539..ef9ee9363fd5ec0b46f61f9ef8308e99f2912319 100644
--- a/sdk/lib/rendering/box.dart
+++ b/sdk/lib/rendering/box.dart
@@ -893,7 +893,7 @@ class RenderTransform extends RenderProxyBox {
 
   void hitTestChildren(HitTestResult result, { Point position }) {
     Matrix4 inverse = new Matrix4.zero();
-    double det = inverse.copyInverse(_transform);
+    /* double det = */ inverse.copyInverse(_transform);
     // TODO(abarth): Check the determinant for degeneracy.
 
     Vector3 position3 = new Vector3(position.x, position.y, 0.0);
diff --git a/sdk/lib/widgets/ink_well.dart b/sdk/lib/widgets/ink_well.dart
index 95a78daeb0094106e2398eda4cba105c682b8b1b..e40c37014684c679678985b08aa11ce3da0ee928 100644
--- a/sdk/lib/widgets/ink_well.dart
+++ b/sdk/lib/widgets/ink_well.dart
@@ -65,14 +65,15 @@ class RenderInkWell extends RenderProxyBox {
   final List<InkSplash> _splashes = new List<InkSplash>();
 
   void handleEvent(sky.Event event, BoxHitTestEntry entry) {
-    switch (event.type) {
-      case 'gesturetapdown':
-        // TODO(abarth): We should position the splash at the location of the tap.
-        _startSplash(event.primaryPointer, entry.localPosition);
-        break;
-      case 'gesturetap':
-        _confirmSplash(event.primaryPointer);
-        break;
+    if (event is sky.GestureEvent) {
+      switch (event.type) {
+        case 'gesturetapdown':
+          _startSplash(event.primaryPointer, entry.localPosition);
+          break;
+        case 'gesturetap':
+          _confirmSplash(event.primaryPointer);
+          break;
+      }
     }
   }
 
diff --git a/sdk/lib/widgets/widget.dart b/sdk/lib/widgets/widget.dart
index 0773cd5ec13177dc58e4ba02853e0179857abaed..9b4001eff9292b7c84cd71edd81242dc4b024860 100644
--- a/sdk/lib/widgets/widget.dart
+++ b/sdk/lib/widgets/widget.dart
@@ -109,11 +109,11 @@ abstract class Widget {
   // Returns the child which should be retained as the child of this node.
   Widget syncChild(Widget node, Widget oldNode, dynamic slot) {
 
-    assert(oldNode is! Component || !oldNode._disqualifiedFromEverAppearingAgain);
+    assert(oldNode is! Component || (oldNode is Component && !oldNode._disqualifiedFromEverAppearingAgain)); // TODO(ianh): Simplify this once the analyzer is cleverer
 
     if (node == oldNode) {
       assert(node == null || node.mounted);
-      assert(node is! RenderObjectWrapper || node._ancestor != null);
+      assert(node is! RenderObjectWrapper || (node is RenderObjectWrapper && node._ancestor != null)); // TODO(ianh): Simplify this once the analyzer is cleverer
       return node; // Nothing to do. Subtrees must be identical.
     }
 
@@ -495,7 +495,7 @@ abstract class RenderObjectWrapper extends Widget {
   void insertChildRoot(RenderObjectWrapper child, dynamic slot);
   void detachChildRoot(RenderObjectWrapper child);
 
-  void _sync(Widget old, dynamic slot) {
+  void _sync(RenderObjectWrapper old, dynamic slot) {
     // TODO(abarth): We should split RenderObjectWrapper into two pieces so that
     //               RenderViewObject doesn't need to inherit all this code it
     //               doesn't need.