rust/src/test/run-pass/cfg_attr.rs
Alex Crichton 3cb9fa26ef std: Rename Show/String to Debug/Display
This commit is an implementation of [RFC 565][rfc] which is a stabilization of
the `std::fmt` module and the implementations of various formatting traits.
Specifically, the following changes were performed:

[rfc]: https://github.com/rust-lang/rfcs/blob/master/text/0565-show-string-guidelines.md

* The `Show` trait is now deprecated, it was renamed to `Debug`
* The `String` trait is now deprecated, it was renamed to `Display`
* Many `Debug` and `Display` implementations were audited in accordance with the
  RFC and audited implementations now have the `#[stable]` attribute
  * Integers and floats no longer print a suffix
  * Smart pointers no longer print details that they are a smart pointer
  * Paths with `Debug` are now quoted and escape characters
* The `unwrap` methods on `Result` now require `Display` instead of `Debug`
* The `Error` trait no longer has a `detail` method and now requires that
  `Display` must be implemented. With the loss of `String`, this has moved into
  libcore.
* `impl<E: Error> FromError<E> for Box<Error>` now exists
* `derive(Show)` has been renamed to `derive(Debug)`. This is not currently
  warned about due to warnings being emitted on stage1+

While backwards compatibility is attempted to be maintained with a blanket
implementation of `Display` for the old `String` trait (and the same for
`Show`/`Debug`) this is still a breaking change due to primitives no longer
implementing `String` as well as modifications such as `unwrap` and the `Error`
trait. Most code is fairly straightforward to update with a rename or tweaks of
method calls.

[breaking-change]
Closes #21436
2015-01-20 22:36:13 -08:00

60 lines
1.6 KiB
Rust

// Copyright 2014 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 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
// compile-flags:--cfg set1 --cfg set2
#![allow(dead_code)]
use std::fmt::Debug;
struct NotDebugable;
#[cfg_attr(set1, derive(Debug))]
struct Set1;
#[cfg_attr(notset, derive(Debug))]
struct Notset(NotDebugable);
#[cfg_attr(not(notset), derive(Debug))]
struct NotNotset;
#[cfg_attr(not(set1), derive(Debug))]
struct NotSet1(NotDebugable);
#[cfg_attr(all(set1, set2), derive(Debug))]
struct AllSet1Set2;
#[cfg_attr(all(set1, notset), derive(Debug))]
struct AllSet1Notset(NotDebugable);
#[cfg_attr(any(set1, notset), derive(Debug))]
struct AnySet1Notset;
#[cfg_attr(any(notset, notset2), derive(Debug))]
struct AnyNotsetNotset2(NotDebugable);
#[cfg_attr(all(not(notset), any(set1, notset)), derive(Debug))]
struct Complex;
#[cfg_attr(any(notset, not(any(set1, notset))), derive(Debug))]
struct ComplexNot(NotDebugable);
#[cfg_attr(any(target_endian = "little", target_endian = "big"), derive(Debug))]
struct KeyValue;
fn is_show<T: Debug>() {}
fn main() {
is_show::<Set1>();
is_show::<NotNotset>();
is_show::<AllSet1Set2>();
is_show::<AnySet1Notset>();
is_show::<Complex>();
is_show::<KeyValue>();
}