message: Don't create HashMap<K, V> when not needed
diff: @@ -27,13 +27,12 @@ fn test_map<S: BuildHasher>(mut map: HashMap<i32, i32, S>) {
  }
  fn main() {
  - let _map : HashMap<i32, i32, BuildHasherDefault<collections::hash_map::DefaultHasher>> = Default::default();
  -
  // TODO: Implement random number generation on OS X
  if cfg!(not(target_os = "macos")) {
  let map_normal: HashMap<i32, i32> = HashMap::new();
  test_map(map_normal);
  } else {
  - test_map(_map);
  + let map : HashMap<i32, i32, BuildHasherDefault<collections::hash_map::DefaultHasher>> = Default::default();
  + test_map(map);
  }
  }
  