| // run-pass |
| #![allow(dead_code)] |
| // pretty-expanded FIXME #23616 |
| |
| use std::rc::Rc; |
| |
| fn lub_short<'a, T>(_: &[&'a T], _: &[&'a T]) {} |
| |
| // The two arguments are a subtype of their LUB, after coercion. |
| fn long_and_short<'a, T>(xs: &[&'static T; 1], ys: &[&'a T; 1]) { |
| lub_short(xs, ys); |
| } |
| |
| // The argument coerces to a subtype of the return type. |
| fn long_to_short<'a, 'b, T>(xs: &'b [&'static T; 1]) -> &'b [&'a T] { |
| xs |
| } |
| |
| // Rc<T> is covariant over T just like &T. |
| fn long_to_short_rc<'a, T>(xs: Rc<[&'static T; 1]>) -> Rc<[&'a T]> { |
| xs |
| } |
| |
| // LUB-coercion (if-else/match/array) coerces `xs: &'b [&'static T: N]` |
| // to a subtype of the LUB of `xs` and `ys` (i.e., `&'b [&'a T]`), |
| // regardless of the order they appear (in if-else/match/array). |
| fn long_and_short_lub1<'a, 'b, T>(xs: &'b [&'static T; 1], ys: &'b [&'a T]) { |
| let _order1 = [xs, ys]; |
| let _order2 = [ys, xs]; |
| } |
| |
| // LUB-coercion should also have the exact same effect when `&'b [&'a T; N]` |
| // needs to be coerced, i.e., the resulting type is not &'b [&'static T], but |
| // rather the `&'b [&'a T]` LUB. |
| fn long_and_short_lub2<'a, 'b, T>(xs: &'b [&'static T], ys: &'b [&'a T; 1]) { |
| let _order1 = [xs, ys]; |
| let _order2 = [ys, xs]; |
| } |
| |
| fn main() {} |