Construction of a void Type?

Question

I was given a piece of code that uses void() as an argument. The code doesn\'t compile... obviously?

Can we instantiate anything of type void

Answer 1

You can use void() as a callable type, as an example std::function f; is a valid statement.

Moreover, as from 8.3.5/4:

A parameter list consisting of a single unnamed parameter of non-dependent type void is equivalent to an empty parameter list.

That means that this is valid:

template
struct F;

template
struct F { };

int main () {
   F s;
}

Here you are not instantiating anything of type void, but you are using it (let me say) as a parameter list of a callable type.

Not sure if this replies to your question, I've not clear what the question actually is.