function not callable using struct constructor

[alex burton]

struct Foo
{
};

void bar(ref Foo f)
{
}
void main()
{
	bar(Foo());		//Error: function test.bar (ref Foo f) is not 
callable using argument types (Foo)
}

I get the above error with 2.064 not with 2.060.
Is it a bug ?

Is it a feature ?
If so :
Why can't I take a non const ref to a temp struct - It might look 
a bit silly but I might be doing it to avoid copying.

I could still do this :

void main()
{
        Foo f = Foo();
        bar(f);
}

Which is equivalent AFAIK