//ww:run-exit 80
package main;
type box = struct { pc: i64, a: i64 };
let calls: i64 = 0;
fn lastidx(xs: []box) i64 = {
	calls += 1;
	let n: i64 = len(xs): i64;
	return n - 1;
};
export fn main() i32 = {
	let bs: []box = [];
	append(bs, box { pc = 11, a = 1 });
	append(bs, box { pc = 4242, a = 2 });
	append(bs, bs[lastidx(bs)]);
	if (calls != 1) { return 1; };
	if (len(bs) != 3) { return 2; };
	if (bs[2].pc != 4242 || bs[2].a != 2) { return 3; };
	if (bs[0].pc != 11) { return 4; };
	return 80;
};