const(Object)ref is here!

[Andrej Mitrovic]

Actually I really like the optional usage of ref here because it might
help to disambiguate between a class and a struct object:

E.g.:

class Foo
{
}

struct Bar
{
}

void main()
{
    Foo ref foo;  // I can be sure Foo is a class
    Bar bar;
}

Sometimes it happens that I forget to 'new' a class object, and to the
naked eye the code doesn't appear wrong, but using the optional ref
keyword helps in tracking this kind of bug down. I guess the compiler
should throw an error in cases where Foo is a struct.