System.NullReferenceException :
   в ClassWithNullable.GetHashCode()
   в CallSite.Target(Closure, CallSite, Object)
   в System.Dynamic.UpdateDelegates.UpdateAndExecute1<T0,TRet>(CallSite site, T0 arg0)
   в IntegrationTests.GetHashCode_should_return_value_for_null_nullable() в IntegrationTests.cs: line 281