// Copyright 2014 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 or the MIT license // , at your // option. This file may not be copied, modified, or distributed // except according to those terms. struct MyPtr<'a>(&'a mut uint); impl<'a> Deref for MyPtr<'a> { fn deref<'b>(&'b self) -> &'b uint { self.0 } } trait Tr { fn poke(&self, s: &mut uint); } impl Tr for uint { fn poke(&self, s: &mut uint) { *s = 2; } } fn main() { let s = &mut 1u; MyPtr(s).poke(s); //~^ ERROR cannot borrow `*s` as mutable more than once at a time }