Failed to overload unary operator

Elements C#
1 
public class TestClass {
    public static void test() {
        var obj = new MyClass();
        // (E119) Cannot use the unary operator "not" on type "MyClass"
        // for Echoes/Cooper/Nougat
        var b = !obj;
    }
}

public class MyClass{
    public static bool operator !(MyClass a)=> false;
}

Elements 8.3.90.1922

2

Thanks, logged as bugs://74294

3

bugs://74294 got closed with status fixed.