[Crash] Cannot cast nullable function param

[farism]

using System;

namespace TryBeef;

class Program {
	public static void Main(String[] args) {
		void Fn(float? a) {
			let b = (double?)a;  // crashes IDE when compiling
		}

		float? a = 0;
		let b = (double?)a; // this works

	        Console.WriteLine(b);
	}
}

https://trybeef.netlify.app/#/giHPmS

nullable_float_param_cast_to_nullable_double.zip