// Copyright 2016 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 or the MIT license // , at your // option. This file may not be copied, modified, or distributed // except according to those terms. // rustc-env:RUST_NEW_ERROR_FORMAT fn main() { let mut v = vec![Some("foo"), Some("bar")]; v.push(v.pop().unwrap()); }