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1 | // Copyright 2014 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. | |
4 | // | |
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. | |
10 | ||
11 | use std::ops::{Index, IndexMut}; | |
12 | ||
13 | struct Foo { | |
14 | x: isize, | |
15 | y: isize, | |
16 | } | |
17 | ||
c34b1796 | 18 | impl<'a> Index<&'a String> for Foo { |
1a4d82fc JJ |
19 | type Output = isize; |
20 | ||
c34b1796 | 21 | fn index(&self, z: &String) -> &isize { |
85aaf69f | 22 | if *z == "x" { |
1a4d82fc JJ |
23 | &self.x |
24 | } else { | |
25 | &self.y | |
26 | } | |
27 | } | |
28 | } | |
29 | ||
c34b1796 AL |
30 | impl<'a> IndexMut<&'a String> for Foo { |
31 | fn index_mut(&mut self, z: &String) -> &mut isize { | |
85aaf69f | 32 | if *z == "x" { |
1a4d82fc JJ |
33 | &mut self.x |
34 | } else { | |
35 | &mut self.y | |
36 | } | |
37 | } | |
38 | } | |
39 | ||
40 | struct Bar { | |
41 | x: isize, | |
42 | } | |
43 | ||
44 | impl Index<isize> for Bar { | |
45 | type Output = isize; | |
46 | ||
c34b1796 | 47 | fn index<'a>(&'a self, z: isize) -> &'a isize { |
1a4d82fc JJ |
48 | &self.x |
49 | } | |
50 | } | |
51 | ||
52 | fn main() { | |
53 | let mut f = Foo { | |
54 | x: 1, | |
55 | y: 2, | |
56 | }; | |
57 | let mut s = "hello".to_string(); | |
58 | let rs = &mut s; | |
c34b1796 | 59 | println!("{}", f[&s]); |
1a4d82fc | 60 | //~^ ERROR cannot borrow `s` as immutable because it is also borrowed as mutable |
c34b1796 | 61 | f[&s] = 10; |
1a4d82fc JJ |
62 | //~^ ERROR cannot borrow `s` as immutable because it is also borrowed as mutable |
63 | let s = Bar { | |
64 | x: 1, | |
65 | }; | |
66 | s[2] = 20; | |
67 | //~^ ERROR cannot assign to immutable indexed content | |
68 | } |