Zero warnings from the analyzer!

sky/sdk/lib/rendering/box.dart

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 import 'dart:math' as math;
 import 'dart:sky' as sky;
 
 import 'package:vector_math/vector_math.dart';
 
 import '../base/debug.dart';
@@ skipping 875 matching lines @@
     markNeedsPaint();
   }
 
   void scale(x, [double y, double z]) {
     _transform.scale(x, y, z);
     markNeedsPaint();
   }
 
   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);
     Vector3 transformed3 = inverse.transform3(position3);
     Point transformed = new Point(transformed3.x, transformed3.y);
     super.hitTestChildren(result, position: transformed);
   }
 
   void paint(RenderObjectDisplayList canvas) {
     canvas.save();
@@ skipping 170 matching lines @@
 
   void defaultPaint(RenderObjectDisplayList canvas) {
     RenderBox child = firstChild;
     while (child != null) {
       assert(child.parentData is ParentDataType);
       canvas.paintChild(child, child.parentData.position);
       child = child.parentData.nextSibling;
     }
   }
 }