1 // Copyright 2017 The Rust Project Developers. See the COPYRIGHT
2 // file at the top-level directory of this distribution and at
3 // http://rust-lang.org/COPYRIGHT.
5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
8 // option. This file may not be copied, modified, or distributed
9 // except according to those terms.
11 #[derive(Copy, Clone, Debug, Eq, PartialEq)]
16 fn get(&self) -> Option<&Result<String, String>> {
20 fn mutate(&mut self) { }
24 let mut foo = Foo { };
26 // foo.get() returns type Option<&Result<String, String>>, so
27 // using `string` keeps borrow of `foo` alive. Hence calling
28 // `foo.mutate()` should be an error.
29 while let Some(Ok(string)) = foo.get() {
31 //~^ ERROR cannot borrow `foo` as mutable
32 println!("foo={:?}", *string);