6f99a27886
This implements RFC 39. Omitted lifetimes in return values will now be
inferred to more useful defaults, and an error is reported if a lifetime
in a return type is omitted and one of the two lifetime elision rules
does not specify what it should be.
This primarily breaks two uncommon code patterns. The first is this:
unsafe fn get_foo_out_of_thin_air() -> &Foo {
...
}
This should be changed to:
unsafe fn get_foo_out_of_thin_air() -> &'static Foo {
...
}
The second pattern that needs to be changed is this:
enum MaybeBorrowed<'a> {
Borrowed(&'a str),
Owned(String),
}
fn foo() -> MaybeBorrowed {
Owned(format!("hello world"))
}
Change code like this to:
enum MaybeBorrowed<'a> {
Borrowed(&'a str),
Owned(String),
}
fn foo() -> MaybeBorrowed<'static> {
Owned(format!("hello world"))
}
Closes #15552.
[breaking-change]
49 lines
1.3 KiB
Rust
49 lines
1.3 KiB
Rust
// Copyright 2012-2014 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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// ignore-pretty
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// (Closes #7911) Test that we can use the same self expression
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// with different mutability in macro in two methods
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#![allow(unused_variable)] // unused foobar_immut + foobar_mut
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#![feature(macro_rules)]
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trait FooBar {}
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struct Bar(i32);
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struct Foo { bar: Bar }
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impl FooBar for Bar {}
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trait Test {
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fn get_immut(&self) -> &FooBar;
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fn get_mut(&mut self) -> &mut FooBar;
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}
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macro_rules! generate_test(($type_:path, $slf:ident, $field:expr) => (
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impl Test for $type_ {
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fn get_immut(&$slf) -> &FooBar {
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&$field as &FooBar
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}
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fn get_mut(&mut $slf) -> &mut FooBar {
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&mut $field as &mut FooBar
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}
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}
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))
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generate_test!(Foo, self, self.bar)
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pub fn main() {
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let mut foo: Foo = Foo { bar: Bar(42) };
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{ let foobar_immut = foo.get_immut(); }
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{ let foobar_mut = foo.get_mut(); }
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}
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