pub fn main(world: World) -> Void raises {
    let src: [3]Bool = [true, false, true]
    var dst: [3]Bool = [false, false, false]
    let copied: usize = std.mem.copyItems(dst, src)
    let copiedValues: Bool = dst[0] && !dst[1] && dst[2]
    let filled: usize = std.mem.fillItems(dst[1..], true)
    let span: Span<Bool> = dst
    let filledValues: Bool = dst[0] && dst[1] && dst[2]
    let containsOk: Bool = std.mem.contains(span, true) && !std.mem.contains(span, false)
    let lenOk: Bool = std.mem.len(span) == 3 && !std.mem.isEmpty(span)
    let ok: Bool = copied == 3 && copiedValues && filled == 2 && filledValues && containsOk && lenOk
    if ok {
        check world.out.write("std mem bool copy items ok\n")
    }
}