vendor/derivative/tests/rustc-deriving-hash.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 #![allow(non_camel_case_types)]
  12
  13 #[cfg(feature = "use_core")]
  14 extern crate core;
  15
  16 #[macro_use]
  17 extern crate derivative;
  18
  19 use std::hash::{Hash, Hasher};
  20 use std::collections::hash_map::DefaultHasher;
  21
  22 #[derive(Derivative)]
  23 #[derivative(Hash)]
  24 struct Person {
  25     id: u16,
  26     name: String,
  27     phone: u64,
  28 }
  29
  30 // test for hygiene name collisions
  31 #[derive(Derivative)]
  32 #[derivative(Hash)] struct __H__H;
  33 #[derive(Derivative)]
  34 #[allow(dead_code)] #[derivative(Hash)] struct Collision<__H> ( __H );
  35 // TODO(rustc) #[derivative(Hash)] enum Collision<__H> { __H { __H__H: __H } }
  36
  37 #[derive(Derivative)]
  38 #[derivative(Hash)]
  39 enum E { A=1, B }
  40
  41 fn hash<T: Hash>(t: &T) -> u64 {
  42     let mut s = DefaultHasher::new();
  43     t.hash(&mut s);
  44     s.finish()
  45 }
  46
  47 struct FakeHasher<'a>(&'a mut Vec<u8>);
  48 impl<'a> Hasher for FakeHasher<'a> {
  49     fn finish(&self) -> u64 {
  50         unimplemented!()
  51     }
  52
  53     fn write(&mut self, bytes: &[u8]) {
  54         self.0.extend(bytes);
  55     }
  56 }
  57
  58 fn fake_hash(v: &mut Vec<u8>, e: E) {
  59     e.hash(&mut FakeHasher(v));
  60 }
  61
  62 #[test]
  63 fn main() {
  64     let person1 = Person {
  65         id: 5,
  66         name: "Janet".to_string(),
  67         phone: 555_666_777,
  68     };
  69     let person2 = Person {
  70         id: 5,
  71         name: "Bob".to_string(),
  72         phone: 555_666_777,
  73     };
  74     assert_eq!(hash(&person1), hash(&person1));
  75     assert!(hash(&person1) != hash(&person2));
  76
  77     // test #21714
  78     let mut va = vec![];
  79     let mut vb = vec![];
  80     fake_hash(&mut va, E::A);
  81     fake_hash(&mut vb, E::B);
  82     assert!(va != vb);
  83 }