Closures created from functions can't be called immediately

[knarkzel]

V version: V 0.2.4 4d4398f.c97f0c5
OS: linux, "Arch Linux"

What did you do?
Try to call closure from function immediately.

What did you expect to see?
No error with following code:

fn closure() fn () {
	return fn (input string) {
	}
}

fn main() {
	output := closure()('hello')
}

What did you see instead?

./perm.v:10:2: error: expression evaluated but not used
    8 | fn main() {
    9 |     output := closure()
   10 |     ('hello')
      |     ~~~~~~~~~
   11 | }

Workaround for now is to bind closure:

fn main() {
    function := closure()
    output := function('hello')
}