If code wrapped with scripting defines exists in your code, which is required in your Luna build you should also include them in the `Scripting Defines` tab in the Luna UI. Otherwise they wont be compiled.
Then include the name space inside the Luna Window. Navigate to the Code section and the Scripting Defines tab.
Although you are able to select which ones are to be picked up during compilation, Luna implements scripting defines default namespaces that are pre-included in the Luna engine: UNITY_LUNA; UNITY_BUPC; UNITY_5_4_OR_NEWER;