385     use std::{cell::Cell, rc::Rc};  in test_drain()
387     struct Counter(Rc<Cell<u32>>);  in test_drain()
397     let a = Rc::new(Cell::new(0));  in test_drain()
398     let b = Rc::new(Cell::new(0));  in test_drain()
399     let c = Rc::new(Cell::new(0));  in test_drain()
467     use std::{cell::Cell, rc::Rc};  in test_retain()
477     struct Counter(Rc<Cell<u32>>);  in test_retain()
485     let c = Rc::new(Cell::new(0));  in test_retain()
488     map.insert(1, Counter(Rc::clone(&c)));  in test_retain()
489     map.insert(2, Counter(Rc::clone(&c)));  in test_retain()
490     map.insert(3, Counter(Rc::clone(&c)));  in test_retain()
491     map.insert(4, Counter(Rc::clone(&c)));  in test_retain()