// 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 or the MIT license // , at your // option. This file may not be copied, modified, or distributed // except according to those terms. struct boxed_int { f: &int, } fn get(bi: &r/boxed_int) -> &r/int { bi.f } fn with(bi: &r/boxed_int) { // Here, the upcast is allowed because the `boxed_int` type is // contravariant with respect to `&r`. See also // compile-fail/regions-infer-invariance-due-to-mutability.rs let bi: &blk/boxed_int/&blk = bi; assert *get(bi) == 22; } fn main() { let g = 22; let foo = boxed_int { f: &g }; with(&foo); }