Exactly! A couple of years ago, we invested in using the libraries from Microsoft Code Contracts for a couple of projects. It was a really promising and inter

Exactly! A couple of years ago, we invested in using the libraries from Microsoft Code Contracts for a couple of projects. It was a really promising and interesting project. With the libraries you could follow the design-by-contract paradigm in your C# code. So you could specify pre-conditions, post-conditions and invariants. When the code was compiled you could configure the compiler to generate or not generate code for these. And next to the support for the compiler, the pre- and post-conditions and invariants were also explicitly listed in the code documentation, and there was also a static analyzer that gave some hints/warnings or reported inconsistencies at compile-time. This was a project from a research team at Microsoft and we were aware of that (and that the libraries were not officially supported), but still sad to see it go. The code was made open-source, but was never really actively maintained. [0] Next to that, there is also the static analysis from JetBrains (ReSharper, Rider): you can use code annotations that are recognized by the IDE. It can be used for (simple) null/not-null analysis, but also more advanced stuff like indicating that a helper method returns null when its input is null (see the contract annotation). The IDE uses static analysis and then gives hints on where you can simplify code because you added null checks that are not needed, or where you should add a null-check and forgot it. I've noticed several times that this really helps and makes my code better and more stable. And I also noticed in code reviews bugs due to people ignoring warnings from this kind of analysis. And finally, in the Roslyn compiler, when you use nullable reference types, you get the null/not-null compile-time analysis. I wish the tools would go a lot further than this... [0] https://www.microsoft.com/en-us/research/project/code-contracts/ https://www.microsoft.com/en-us/research/project/code-contra... [1] https://www.jetbrains.com/help/resharper/Reference__Code_Annotation_Attributes.html#ContractAnnotationAttribute https://www.jetbrains.com/help/resharper/Reference__Code_Ann...