// run-pass // Test that we can coerce an `@Object` to an `&Object` trait Foo { fn foo(&self) -> usize; fn bar(&mut self) -> usize; } impl Foo for usize { fn foo(&self) -> usize { *self } fn bar(&mut self) -> usize { *self += 1; *self } } fn do_it_mut(obj: &mut dyn Foo) { let x = obj.bar(); let y = obj.foo(); assert_eq!(x, y); do_it_imm(obj, y); } fn do_it_imm(obj: &dyn Foo, v: usize) { let y = obj.foo(); assert_eq!(v, y); } pub fn main() { let mut x: usize = 22; let obj = &mut x as &mut dyn Foo; do_it_mut(obj); do_it_imm(obj, 23); do_it_mut(obj); }