src/test/run-pass/issue-32008.rs

   1 // Copyright 2017 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 // Tests that binary operators allow subtyping on both the LHS and RHS,
  12 // and as such do not introduce unnecesarily strict lifetime constraints.
  13
  14 use std::ops::Add;
  15
  16 struct Foo;
  17
  18 impl<'a> Add<&'a Foo> for &'a Foo {
  19     type Output = ();
  20     fn add(self, rhs: &'a Foo) {}
  21 }
  22
  23 fn try_to_add(input: &Foo) {
  24     let local = Foo;
  25
  26     // Manual reborrow worked even with invariant trait search.
  27     &*input + &local;
  28
  29     // Direct use of the reference on the LHS requires additional
  30     // subtyping before searching (invariantly) for `LHS: Add<RHS>`.
  31     input + &local;
  32 }
  33
  34 fn main() {
  35 }