Optional parameters on delegates doesn't work properly [duplicate]

Answer 1

Try this way:

static int f(bool a)
{
  return 4;
}

Answer 2

What will happen test(false)? It will corrupt the stack, because signatures must match.

Answer 3

Optional parameters are for use on the calling side - not on what is effectively like a single-method-interface implementation. So for example, this should compile:

delegate void SimpleDelegate(bool x = true);

static void Main()
{
    SimpleDelegate x = Foo;
    x(); // Will print "True"
}

static void Foo(bool y)
{
    Console.WriteLine(y);
}

Answer 4

Because optional parameters do not change the underlying signature of the method, which is important to delegates.

What your code is expecting is the optional parameter to not be in the method signature if you don't use it - this is incorrect.