src/test/compile-fail/on-unimplemented/on-impl.rs

   1 // Copyright 2016 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 if the on_unimplemented message override works
  12
  13 #![feature(on_unimplemented)]
  14 #![feature(rustc_attrs)]
  15
  16 #[rustc_on_unimplemented = "invalid"]
  17 trait Index<Idx: ?Sized> {
  18     type Output: ?Sized;
  19     fn index(&self, index: Idx) -> &Self::Output;
  20 }
  21
  22 #[rustc_on_unimplemented = "a usize is required to index into a slice"]
  23 impl Index<usize> for [i32] {
  24     type Output = i32;
  25     fn index(&self, index: usize) -> &i32 {
  26         &self[index]
  27     }
  28 }
  29
  30 #[rustc_error]
  31 fn main() {
  32     Index::<u32>::index(&[1, 2, 3] as &[i32], 2u32);
  33     //~^ ERROR E0277
  34     //~| NOTE a usize is required
  35     //~| NOTE required by
  36 }