| // Copyright 2012 The Rust Project Developers. See the COPYRIGHT |
| // file at the top-level directory of this distribution and at |
| // http://rust-lang.org/COPYRIGHT. |
| // |
| // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or |
| // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license |
| // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your |
| // option. This file may not be copied, modified, or distributed |
| // except according to those terms. |
| |
| #![allow(warnings)] |
| |
| // Here the type of `c` is `Option<?T>`, where `?T` is unconstrained. |
| // Because there is data-flow from the `{ return; }` block, which |
| // diverges and hence has type `!`, into `c`, we will default `?T` to |
| // `!`, and hence this code compiles rather than failing and requiring |
| // a type annotation. |
| |
| fn main() { |
| let c = Some({ return; }); |
| c.unwrap(); |
| } |
