"Demonstration that Optional and Params Args Require Var"

sealed class TestClass {
	static readonly Func<string, int, string> _multiplierFunc = (string input, int numMultiples = 2) => String.Join(null, Enumerable.Repeat(input, numMultiples));
	static readonly Func<string[], string> _joinFunc = (params string[] input) => String.Join(null, input);

	static void Test() {
		_multiplierFunc("hello"); // doesn't compile 
		_joinFunc("hi", " ", "there"); // doesn't compile
	}
}