| // 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. |
| |
| enum Either<T, U> { Left(T), Right(U) } |
| |
| struct X(Either<(usize,usize), fn()>); |
| |
| impl X { |
| pub fn with<F>(&self, blk: F) where F: FnOnce(&Either<(usize, usize), fn()>) { |
| let X(ref e) = *self; |
| blk(e) |
| } |
| } |
| |
| fn main() { |
| let mut x = X(Either::Right(main as fn())); |
| (&mut x).with( |
| |opt| { //~ ERROR cannot borrow `x` as mutable more than once at a time |
| match opt { |
| &Either::Right(ref f) => { |
| x = X(Either::Left((0, 0))); |
| (*f)() |
| }, |
| _ => panic!() |
| } |
| }) |
| } |
