// 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. use std::fmt; #[deny(warnings)] trait Foo { fn foo(&self) -> (Self, Self); } //~^ ERROR the trait bound `Self: std::marker::Sized` is not satisfied //~| WARNING hard error impl Foo for T { fn foo(&self) -> (Self, Self) { (*self, *self) } } #[deny(warnings)] fn main() { assert_eq!((11).foo(), (11, 11)); let junk: Box = Box::new(42); //~^ ERROR the trait cannot require that `Self : Sized` //~| WARNING hard error let f = format!("{:?}", junk); assert_eq!(f, "42"); }