// Copyright 2016 The Rust Project Developers. See the COPYRIGHT // file at the top-level directory of this distribution and at // http://rust-lang.org/COPYRIGHT. // // Licensed under the Apache License, Version 2.0 or the MIT license // , at your // option. This file may not be copied, modified, or distributed // except according to those terms. #![feature(untagged_unions)] #[derive(Clone)] //~ ERROR the trait bound `U1: std::marker::Copy` is not satisfied union U1 { a: u8, } #[derive(Clone)] union U2 { a: u8, // OK } impl Copy for U2 {} #[derive(Clone, Copy)] union U3 { a: u8, // OK } #[derive(Clone, Copy)] union U4 { a: T, // OK } #[derive(Clone)] struct CloneNoCopy; fn main() { let u = U4 { a: CloneNoCopy }; let w = u.clone(); //~ ERROR no method named `clone` found for type `U4` }