3 // Fast path, main can see the concrete type returned.
4 fn before() -> impl FnMut(i32) {
5 let mut p = Box::new(0);
9 fn send<T: Send>(_: T) {}
16 // Deferred path, main has to wait until typeck finishes,
17 // to check if the return type of after is Send.
18 fn after() -> impl FnMut(i32) {
19 let mut p = Box::new(0);