For C#, and all .NET languages, there are Code Contracts. I've never used them, but they seem to be maintained and relatively easy to use. The docs, with a good

For C#, and all .NET languages, there are Code Contracts. I've never used them, but they seem to be maintained and relatively easy to use. The docs, with a good example at the end, are here: https://docs.microsoft.com/en-us/dotnet/framework/debug-trace-profile/code-contracts https://docs.microsoft.com/en-us/dotnet/framework/debug-trac... Edit: Actually it seems abandoned, with no support for .NET Core right now. Shame.