gistfile1.txt

    * The `Copy` trait no longer implemented automatically and `Sync`
      and `Share` aro no longer implemented automatically for types
      containing unsafe pointers. `Sync` and `Share` are now 'unsafe
      traits' for which implementations require an `unsafe impl`
      declaration. These changes are intended to prevent some footguns
      and are collectively known as [opt-in built-in traits][oibit]
      (though `Sync` and `Share` will soon become pure library types
      unknown to the compiler).