-Subproject commit 1abfbaa70313fdf527cf799ffd9b9a096a62105c
+Subproject commit 266d429a48468371d2d90669f6a30dd659bb4bdb
+++ /dev/null
-# `rvalue_static_promotion`
-
-The tracking issue for this feature is: [#38865]
-
-[#38865]: https://github.com/rust-lang/rust/issues/38865
-
-------------------------
-
-The `rvalue_static_promotion` feature allows directly creating `'static` references to
-constant `rvalue`s, which in particular allowing for more concise code in the common case
-in which a `'static` reference is all that's needed.
-
-
-## Examples
-
-```rust
-#![feature(rvalue_static_promotion)]
-
-fn main() {
- let DEFAULT_VALUE: &'static u32 = &42;
- assert_eq!(*DEFAULT_VALUE, 42);
-}
-```
let promotable = self.tcx.rvalue_promotable_to_static.borrow().get(&id).cloned()
.unwrap_or(false);
- // When the corresponding feature isn't toggled, only promote `[T; 0]`.
+ // Always promote `[T; 0]` (even when e.g. borrowed mutably).
let promotable = match expr_ty.sty {
ty::TyArray(_, 0) => true,
- _ => promotable && self.tcx.sess.features.borrow().rvalue_static_promotion,
+ _ => promotable,
};
// Compute maximum lifetime of this rvalue. This is 'static if
// Allows `repr(align(u16))` struct attribute (RFC 1358)
(active, repr_align, "1.17.0", Some(33626)),
- // See rust-lang/rfcs#1414. Allows code like `let x: &'static u32 = &42` to work.
- (active, rvalue_static_promotion, "1.15.1", Some(38865)),
-
// Used to preserve symbols (see llvm.used)
(active, used, "1.18.0", Some(40289)),
(accepted, associated_consts, "1.20.0", Some(29646)),
// Usage of the `compile_error!` macro
(accepted, compile_error, "1.20.0", Some(40872)),
+ // See rust-lang/rfcs#1414. Allows code like `let x: &'static u32 = &42` to work.
+ (accepted, rvalue_static_promotion, "1.21.0", Some(38865)),
);
// If you change this, please modify src/doc/unstable-book as well. You must
// Test lifetimes are linked properly when we take reference
// to interior.
+fn id<T>(x: T) -> T { x }
+
struct Foo(isize);
fn foo<'a>() -> &'a isize {
- let &Foo(ref x) = &Foo(3); //~ ERROR borrowed value does not live long enough
+ let &Foo(ref x) = &id(Foo(3)); //~ ERROR borrowed value does not live long enough
x
}
+++ /dev/null
-// Copyright 2017 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.
-
-#[allow(unused_variables)]
-fn main() {
- let x: &'static u32 = &42; //~ error: does not live long enough
- let y: &'static Option<u32> = &None; //~ error: does not live long enough
-}
// This file must never have a trailing newline
+fn id<T>(x: T) -> T { x }
+
fn main() {
let x = Some(3);
- let y = x.as_ref().unwrap_or(&5); //~ ERROR: borrowed value does not live long enough
+ let y = x.as_ref().unwrap_or(&id(5)); //~ ERROR: borrowed value does not live long enough
}
#![feature(fn_traits)]
+fn id<T>(x: T) -> T { x }
+
pub fn foo<'a, F: Fn(&'a ())>(bar: F) {
bar.call((
- &(), //~ ERROR borrowed value does not live long enough
+ &id(()), //~ ERROR borrowed value does not live long enough
));
}
fn main() {}
// option. This file may not be copied, modified, or distributed
// except according to those terms.
+fn id<T>(x: T) -> T { x }
+
const FOO: usize = 3;
-fn foo() -> &'static usize { &FOO }
+fn foo() -> &'static usize { &id(FOO) }
//~^ ERROR: borrowed value does not live long enough
fn main() {
// option. This file may not be copied, modified, or distributed
// except according to those terms.
-// Regression test for issue #27591.
+// Regression test for issue #27592.
fn write<'a, F: ::std::ops::FnOnce()->::std::fmt::Arguments<'a> + 'a>(fcn: F) {
use std::fmt::Write;
}
fn main() {
- write(|| format_args!("{}", "Hello world"));
+ write(|| format_args!("{}", String::from("Hello world")));
//~^ ERROR borrowed value does not live long enough
//~| ERROR borrowed value does not live long enough
}
// are treated as rvalues and their lifetime is not bounded to
// the static scope.
+fn id<T>(x: T) -> T { x }
+
struct Test;
enum MyEnum {
}
fn structLifetime<'a>() -> &'a Test {
- let testValue = &Test; //~ ERROR borrowed value does not live long enough
+ let testValue = &id(Test);
+ //~^ ERROR borrowed value does not live long enough
testValue
}
fn variantLifetime<'a>() -> &'a MyEnum {
- let testValue = &MyEnum::Variant1; //~ ERROR borrowed value does not live long enough
+ let testValue = &id(MyEnum::Variant1);
+ //~^ ERROR borrowed value does not live long enough
testValue
}
// option. This file may not be copied, modified, or distributed
// except according to those terms.
+fn id<T>(x: T) -> T { x }
+
fn f(_x: &isize) -> &isize {
- return &3; //~ ERROR borrowed value does not live long enough
+ return &id(3); //~ ERROR borrowed value does not live long enough
}
fn main() {
// option. This file may not be copied, modified, or distributed
// except according to those terms.
+fn id<T>(x: T) -> T { x }
+
fn foo(cond: bool) {
// Here we will infer a type that uses the
// region of the if stmt then block:
let mut x;
if cond {
- x = &3; //~ ERROR borrowed value does not live long enough
+ x = &id(3); //~ ERROR borrowed value does not live long enough
assert_eq!(*x, 3);
}
}
// option. This file may not be copied, modified, or distributed
// except according to those terms.
+fn id<T>(x: T) -> T { x }
+
struct StateMachineIter<'a> {
statefn: &'a StateMachineFunc<'a>
}
}
fn state1(self_: &mut StateMachineIter) -> Option<&'static str> {
- self_.statefn = &(state2 as StateMachineFunc);
+ self_.statefn = &id(state2 as StateMachineFunc);
//~^ ERROR borrowed value does not live long enough
return Some("state1");
}
fn state2(self_: &mut StateMachineIter) -> Option<(&'static str)> {
- self_.statefn = &(state3 as StateMachineFunc);
+ self_.statefn = &id(state3 as StateMachineFunc);
//~^ ERROR borrowed value does not live long enough
return Some("state2");
}
fn state3(self_: &mut StateMachineIter) -> Option<(&'static str)> {
- self_.statefn = &(finished as StateMachineFunc);
+ self_.statefn = &id(finished as StateMachineFunc);
//~^ ERROR borrowed value does not live long enough
return Some("state3");
}
fn state_iter() -> StateMachineIter<'static> {
StateMachineIter {
- statefn: &(state1 as StateMachineFunc) //~ ERROR borrowed value does not live long enough
+ statefn: &id(state1 as StateMachineFunc)
+ //~^ ERROR borrowed value does not live long enough
}
}
#![feature(box_syntax)]
+fn id<T>(x: T) -> T { x }
+
fn f<T:'static>(_: T) {}
fn main() {
let x: Box<_> = box 3;
f(x);
- let x = &3; //~ ERROR borrowed value does not live long enough
+ let x = &id(3); //~ ERROR borrowed value does not live long enough
f(x);
}
// option. This file may not be copied, modified, or distributed
// except according to those terms.
-#![feature(rvalue_static_promotion)]
-
#[allow(unused_variables)]
fn main() {
let x: &'static u32 = &42;
// except according to those terms.
fn f() {
- let x = [1].iter();
+ let x = vec![1].iter();
}
fn main() {
error[E0597]: borrowed value does not live long enough
- --> $DIR/borrowck-let-suggestion.rs:12:23
+ --> $DIR/borrowck-let-suggestion.rs:12:27
|
-12 | let x = [1].iter();
- | --- ^ temporary value dropped here while still borrowed
+12 | let x = vec![1].iter();
+ | ------- ^ temporary value dropped here while still borrowed
| |
| temporary value created here
13 | }
| - temporary value needs to live until here
|
= note: consider using a `let` binding to increase its lifetime
+ = note: this error originates in a macro outside of the current crate
error: aborting due to previous error
// option. This file may not be copied, modified, or distributed
// except according to those terms.
+fn id<T>(x: T) -> T { x }
+
fn f() {
let old = ['o']; // statement 0
let mut v1 = Vec::new(); // statement 1
let mut v3 = Vec::new(); // statement 5
- v3.push(&'x'); // statement 6
+ v3.push(&id('x')); // statement 6
//~^ ERROR borrowed value does not live long enough
//~| NOTE temporary value created here
//~| NOTE temporary value only lives until here
let mut v4 = Vec::new(); // (sub) statement 0
- v4.push(&'y');
+ v4.push(&id('y'));
//~^ ERROR borrowed value does not live long enough
//~| NOTE temporary value created here
//~| NOTE temporary value only lives until here
let mut v5 = Vec::new(); // statement 8
- v5.push(&'z');
+ v5.push(&id('z'));
//~^ ERROR borrowed value does not live long enough
//~| NOTE temporary value created here
//~| NOTE temporary value only lives until here
error[E0597]: `young[..]` does not live long enough
- --> $DIR/borrowck-let-suggestion-suffixes.rs:52:1
+ --> $DIR/borrowck-let-suggestion-suffixes.rs:54:1
|
-19 | v2.push(&young[0]); // statement 4
+21 | v2.push(&young[0]); // statement 4
| -------- borrow occurs here
...
-52 | }
+54 | }
| ^ `young[..]` dropped here while still borrowed
|
= note: values in a scope are dropped in the opposite order they are created
error[E0597]: borrowed value does not live long enough
- --> $DIR/borrowck-let-suggestion-suffixes.rs:24:18
+ --> $DIR/borrowck-let-suggestion-suffixes.rs:26:22
|
-24 | v3.push(&'x'); // statement 6
- | --- ^ temporary value dropped here while still borrowed
+26 | v3.push(&id('x')); // statement 6
+ | ------- ^ temporary value dropped here while still borrowed
| |
| temporary value created here
...
-52 | }
+54 | }
| - temporary value needs to live until here
|
= note: consider using a `let` binding to increase its lifetime
error[E0597]: borrowed value does not live long enough
- --> $DIR/borrowck-let-suggestion-suffixes.rs:34:22
+ --> $DIR/borrowck-let-suggestion-suffixes.rs:36:26
|
-34 | v4.push(&'y');
- | --- ^ temporary value dropped here while still borrowed
+36 | v4.push(&id('y'));
+ | ------- ^ temporary value dropped here while still borrowed
| |
| temporary value created here
...
-40 | } // (statement 7)
+42 | } // (statement 7)
| - temporary value needs to live until here
|
= note: consider using a `let` binding to increase its lifetime
error[E0597]: borrowed value does not live long enough
- --> $DIR/borrowck-let-suggestion-suffixes.rs:45:18
+ --> $DIR/borrowck-let-suggestion-suffixes.rs:47:22
|
-45 | v5.push(&'z');
- | --- ^ temporary value dropped here while still borrowed
+47 | v5.push(&id('z'));
+ | ------- ^ temporary value dropped here while still borrowed
| |
| temporary value created here
...
-52 | }
+54 | }
| - temporary value needs to live until here
|
= note: consider using a `let` binding to increase its lifetime
// option. This file may not be copied, modified, or distributed
// except according to those terms.
+fn id<T>(x: T) -> T { x }
+
fn main() {
let v = vec![
- &3
+ &id(3)
];
for &&x in &v {
error[E0597]: borrowed value does not live long enough
- --> $DIR/issue-15480.rs:14:6
+ --> $DIR/issue-15480.rs:16:6
|
-13 | &3
- | - temporary value created here
-14 | ];
+15 | &id(3)
+ | ----- temporary value created here
+16 | ];
| ^ temporary value dropped here while still borrowed
...
-19 | }
+21 | }
| - temporary value needs to live until here
|
= note: consider using a `let` binding to increase its lifetime
#![feature(box_syntax)]
+fn id<T>(x: T) -> T { x }
+
trait Foo { }
impl<'a> Foo for &'a isize { }
fn main() {
let blah;
{
- let ss: &isize = &1;
+ let ss: &isize = &id(1);
blah = box ss as Box<Foo>;
}
}
error[E0597]: borrowed value does not live long enough
- --> $DIR/regions-close-over-borrowed-ref-in-obj.rs:22:5
+ --> $DIR/regions-close-over-borrowed-ref-in-obj.rs:24:5
|
-20 | let ss: &isize = &1;
- | - temporary value created here
-21 | blah = box ss as Box<Foo>;
-22 | }
+22 | let ss: &isize = &id(1);
+ | ----- temporary value created here
+23 | blah = box ss as Box<Foo>;
+24 | }
| ^ temporary value dropped here while still borrowed
-23 | }
+25 | }
| - temporary value needs to live until here
error: aborting due to previous error
fn main() {
let y;
{
- let x: &[isize] = &[1, 2, 3, 4, 5];
+ let x: &[isize] = &vec![1, 2, 3, 4, 5];
y = &x[1..];
}
}
error[E0597]: borrowed value does not live long enough
--> $DIR/slice-borrow.rs:18:5
|
-16 | let x: &[isize] = &[1, 2, 3, 4, 5];
- | --------------- temporary value created here
+16 | let x: &[isize] = &vec![1, 2, 3, 4, 5];
+ | ------------------- temporary value created here
17 | y = &x[1..];
18 | }
| ^ temporary value dropped here while still borrowed
19 | }
| - temporary value needs to live until here
+ |
+ = note: this error originates in a macro outside of the current crate
error: aborting due to previous error
projects / rust.git / commitdiff