Roslyn

Roslyn is the .NET Compiler Platform: open-source C# and Visual Basic compilers exposed as APIs for deep code analysis and generation.

Roslyn, the .NET Compiler Platform, fundamentally shifts the compiler model: it moves from an opaque translator to a platform. This open-source project (github.com/dotnet/roslyn) provides C# and Visual Basic compilers as APIs, allowing developers to access the full syntax tree and semantic model of their code. This capability enables advanced tooling like real-time IntelliSense, comprehensive refactoring, custom code analyzers, and code fixes, which are now integral to Visual Studio and other .NET IDEs. You use the Roslyn SDK to build these powerful, language-aware tools.

https://learn.microsoft.com/en-us/dotnet/csharp/roslyn-sdk/