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]
62 lines
1.3 KiB
Rust
62 lines
1.3 KiB
Rust
// Copyright 2013 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.
|
|
|
|
/*
|
|
# ICE when returning struct with reference to trait
|
|
|
|
A function which takes a reference to a trait and returns a
|
|
struct with that reference results in an ICE.
|
|
|
|
This does not occur with concrete types, only with references
|
|
to traits.
|
|
*/
|
|
|
|
|
|
// original
|
|
trait Inner {
|
|
fn print(&self);
|
|
}
|
|
|
|
impl Inner for int {
|
|
fn print(&self) { print!("Inner: {}\n", *self); }
|
|
}
|
|
|
|
struct Outer<'a> {
|
|
inner: &'a Inner
|
|
}
|
|
|
|
impl<'a> Outer<'a> {
|
|
fn new(inner: &Inner) -> Outer {
|
|
Outer {
|
|
inner: inner
|
|
}
|
|
}
|
|
}
|
|
|
|
pub fn main() {
|
|
let inner = 5i;
|
|
let outer = Outer::new(&inner as &Inner);
|
|
outer.inner.print();
|
|
}
|
|
|
|
|
|
// minimal
|
|
trait MyTrait<T> { }
|
|
|
|
pub struct MyContainer<'a, T> {
|
|
foos: Vec<&'a MyTrait<T>> ,
|
|
}
|
|
|
|
impl<'a, T> MyContainer<'a, T> {
|
|
pub fn add (&mut self, foo: &'a MyTrait<T>) {
|
|
self.foos.push(foo);
|
|
}
|
|
}
|