/// Only needed to prevent lifetime elision
struct Context {
    start: usize,
    end: usize,
}

impl Context {
    fn new(start: usize, end: usize) -> Self {
        Self { start, end }
    }
}

/// Some kind of genralized ArrayIter as you want.
struct SliceWrapper<'a, T>(&'a [T]);

impl<'a, T> SliceWrapper<'a, T> {
    fn with_context(i: &'a [T], c: &Context) -> SliceWrapper<'a, T> {
        SliceWrapper( &i[c.start..c.end] )
    }
}

fn main() {
    let mut array = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9];
    let c = Context::new(2, 4);
    let sw = SliceWrapper::with_context(&array, &c);

    // this fails because array is still borrowed immutable by sw
    // array[4] = 15;

    for number in sw.0.iter() {
        print!("{},", number);
    }
}