| // Copyright 2015 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. |
| |
| // Check that we properly record borrows when we are doing an |
| // overloaded, autoderef of a value obtained via an overloaded index |
| // operator. The accounting of the all the implicit things going on |
| // here is rather subtle. Issue #20232. |
| |
| // revisions: ast mir |
| //[mir]compile-flags: -Z borrowck=mir |
| |
| use std::ops::{Deref, Index}; |
| |
| struct MyVec<T> { x: T } |
| |
| impl<T> Index<usize> for MyVec<T> { |
| type Output = T; |
| fn index(&self, _: usize) -> &T { |
| &self.x |
| } |
| } |
| |
| struct MyPtr<T> { x: T } |
| |
| impl<T> Deref for MyPtr<T> { |
| type Target = T; |
| fn deref(&self) -> &T { |
| &self.x |
| } |
| } |
| |
| struct Foo { f: usize } |
| |
| fn main() { |
| let mut v = MyVec { x: MyPtr { x: Foo { f: 22 } } }; |
| let i = &v[0].f; |
| v = MyVec { x: MyPtr { x: Foo { f: 23 } } }; |
| //[ast]~^ ERROR cannot assign to `v` |
| //[mir]~^^ ERROR cannot assign to `v` because it is borrowed |
| read(*i); |
| } |
| |
| fn read(_: usize) { } |