//ww:run-exit 75
package main;
type box = struct { pc: size, a: i64, b: i64, x: i64 };
export fn main() i32 = {
	let bs: []box = [];
	append(bs, box { pc = 1, a = 10, ... });
	append(bs, box { pc = 2, a = 20, ... });
	append(bs, box { pc = 3, a = 30, b = 7, x = 8 });
	let ds: []box = [];
	let i: i64 = 1;
	append(ds, bs[i + 1]);
	if (len(ds) != 1) { return 1; };
	if (ds[0].pc != 3) { return 2; };
	if (ds[0].a != 30) { return 3; };
	if (ds[0].b != 7 || ds[0].x != 8) { return 4; };
	return 75;
};