type IntWindow {
    values: Span<i32>,
}

fn second(values: Span<i32>) -> i32 {
    return values[1]
}

fn middle(values: Span<i32>) -> Span<i32> {
    return values[1..4]
}

fn spanTail(values: Span<i32>) -> Span<i32> {
    return values[2..5]
}

pub fn main(world: World) -> Void raises {
    let values: [5]i32 = [10, 20, 30, 40, 50]
    let span: Span<i32> = values
    let start: usize = 1
    let end: usize = 4
    let fromArray: Span<i32> = values[start..end]
    let fromSpan: Span<i32> = span[start..end]
    let window: IntWindow = IntWindow { values: middle(span) }
    if values[2] == 30 && second(span) == 20 && fromArray[0] == 20 && fromArray[2] == 40 && fromSpan[1] == 30 && window.values[2] == 40 && spanTail(span)[0] == 30 {
        check world.out.write("generic spans ok\n")
    }
}