Failed to use lambda with mixed regular/ref/out args

public delegate bool TestDelegate(object arg, ref object refArg, out object outArg);

public class TestClass {

    public static void test() {
        // Lots of compile errors for Echoes/Cooper/Nougat
        // Works fine for Microsoft C#
        doSth((object obj, ref object refArg, out object outArg) => {
            outArg = new object();
            return true;

    public static void doSth(TestDelegate func) {
        object refArg = null;
        object outArg = null;
        func(null, ref refArg, out outArg);


Thanks, logged as bugs://74295

bugs://74295 got closed with status fixed.