src/test/run-pass/regions-infer-reborrow-ref-mut-recurse.rs

   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 // Test an edge case in region inference: the lifetime of the borrow
  12 // of `*x` must be extended to at least 'a.
  13
  14 // pretty-expanded FIXME #23616
  15
  16 fn foo<'a,'b>(x: &'a &'b mut isize) -> &'a isize {
  17     let y = &*x; // should be inferred to have type &'a &'b mut isize...
  18
  19     // ...because if we inferred, say, &'x &'b mut isize where 'x <= 'a,
  20     // this reborrow would be illegal:
  21     &**y
  22 }
  23
  24 pub fn main() {
  25     /* Just want to know that it compiles. */
  26 }