anchor.diff:        : animList = new List<BoneAnimation>(length);
   
     void InsertBone(BoneAnimation ba) {
  -    assert(animList[ba.boneIndex] == null);
  -    animList[ba.boneIndex] = ba;
  +    assert(animList[ba.bone.boneIndex] == null);
  +    animList[ba.bone.boneIndex] = ba;
     }
   }
   
  
positive.code:     VM.Quaternion r = _rotationValues[rotationIndex];
      boneMatrix.setFromTranslationRotationScale(t, r, s);
    }
  }
  
  /// ## Class SkeletalAnimation
  
negative.code: /// ## Class BoneAnimation
  /// represents Key frame animation data for a single bone in a skeleton.
  class BoneAnimation {
    final Bone bone;
  
    List<double> _positionTimes;
    List<VM.Vector3> _positionValues;
  