rust/src/test/compile-fail/borrowck-pat-reassign-sometimes-binding.rs

// 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.

// xfail-pretty -- comments are infaithfully preserved

fn main() {
    let mut x = None;
    match x { //~ NOTE loan of mutable local variable granted here
      None => {
        // It is ok to reassign x here, because there is in
        // fact no outstanding loan of x!
        x = Some(0);
      }
      Some(ref _i) => {
        x = Some(1); //~ ERROR assigning to mutable local variable prohibited due to outstanding loan
      }
    }
    copy x; // just to prevent liveness warnings
}