struct Bar {
	c: usize
}

impl Bar {
	fn add(&mut self) {
		self.c += 1;
	}
}

fn test(bar: Option<&mut Bar>) {
    for _ in 0..10 {
    	if let Some(b) = bar {
	    	b.add();
	    }
	}
}

fn main() {
	let mut bar = Bar{c: 0};
	test(Some(&mut bar));
}