what is this feature called in c# and which version of c# uses this

Question

I am using this line of code in my project and haven`t seen this syntax.

 internal static StringBuilder a(this StringBuilder sb, string b) => sb.Append(b).Ap         


        

Answer 1

If you mean the lambda arrow =>, it is a feature of C# 6 (expression-bodied function members). Check https://github.com/dotnet/roslyn/wiki/New-Language-Features-in-C%23-6#expression-bodied-function-members