fn f() ?int {
	return none
}

fn type_unimplemented_ierror() {
	if _ := f() {
	} else {
		_ = err is int
	}

	_ = f() or {
		_ = err is int
		0
	}
}

interface IAbc {
	some_method()
}

struct Struct {}

fn (s Struct) some_method() {}

fn type_unimplemented_interface() {
	ivalue := IAbc(Struct{})
	_ := ivalue is int
}