.NET Fiddle

CSharp · Console

/Program.cs

using System;

// see: https://stackoverflow.com/q/41288668/1016343
public class Program
{
	public void Main()
	{
		void Main()
		{
			void Main()
			{
				Console.WriteLine("Hello!");
			}
			Main();
		}
		Main();
	}
}
;