Attributes that affect compiled code aren’t a new thing for C#, so this would align with existing patterns. And if we ever get declarative parameter validation, it would look something like this ...

Take advantage of the specification design pattern in C# to improve the modularity, maintainability, and reusability of your source code. Whеn wе work in business applications, our job is to ...

Microsoft’s new C# Dev Kit extension for Visual Studio Code turns the programmer’s editor into a complete development environment for .NET.