Function delegate problems on iOS

Elements C#
1 
public delegate int Func0();

public delegate int Func1(int a);

public class TestClass{

    public void test(){

        doSth0(getNum0); 
        // #1 compile error: (E558) Parenthesis required for call in parameter 1 of Int32 TestClass.doSth0(Func0 f0)
        
        doSth0(new Func0(getNum0)); 
        // #2 compile ok, but will run into exception: 'NSInvalidArgumentException', reason: '+[Protocol getNum0]: unrecognized selector sent to class 0x10b793148'

        doSth1(getNum1);  
        // #3 works fine

        doSth1(TestFuncClass.getNum1);
        // #4 compile ok, but will run into exception: 'NSInvalidArgumentException', reason: '+[Protocol getNum0]: unrecognized selector sent to class 0x10b793148'
    }

    public int doSth0(Func0 f0){
        return f0();
    }

    public int doSth1(Func1 f1){
        return f1(1);
    }

    public static int getNum0(){return 5;}

    public static int getNum1(int a){return a;}
}

public static class TestFuncClass{
    public int getNum1(int a){return a;}
}

I think #1 is a bug no doubt, but not sure about #2 and #4. Are they some by-design limitations?

Elements 8.2.89.1893
EmptyiOS.zip (111.0 KB)

2

Thanks, logged as bugs://73749

3

bugs://73749 got closed with status fixed.