Another important change you will notice in X++ is about the unit of compilation. In Dynamics 365 for Finance and Operations, the X++ compilation unit is now the same as for the other .NET languages such as C#. If any method in a model element (class, form, query, and so on) fails to compile, the whole compilation fails. In the previous version of Microsoft Dynamics AX , you could change a method code and compile that method successfully, which means that if the compilation of a class found an error in one method of the class, the methods that did compile correctly were still runnable. However, at runtime, if the non-compiled method is used, it will throw an error.