-
Notifications
You must be signed in to change notification settings - Fork 12.3k
Commit
This commit does not belong to any branch on this repository, and may belong to a fork outside of the repository.
auto merge of #17784 : bkoropoff/rust/issue-17780, r=pcwalton
This fixes a soundness problem where `Fn` unboxed closures can mutate free variables in the environment.
The following presently builds:
```rust
#![feature(unboxed_closures, overloaded_calls)]
fn main() {
let mut x = 0u;
let _f = |&:| x = 42;
}
```
However, this is equivalent to writing the following, which borrowck rightly rejects:
```rust
struct F<'a> {
x: &'a mut uint
}
impl<'a> Fn<(),()> for F<'a> {
#[rust_call_abi_hack]
fn call(&self, _: ()) {
*self.x = 42; // error: cannot assign to data in a `&` reference
}
}
fn main() {
let mut x = 0u;
let _f = F { x: &mut x };
}
```
This problem is unique to unboxed closures; boxed closures cannot be invoked through an immutable reference and are not subject to it.
This change marks upvars of `Fn` unboxed closures as freely aliasable in mem_categorization, which causes borrowck to reject attempts to mutate or mutably borrow them.
@zwarich pointed out that even with this change, there are remaining soundness issues related to regionck (issue #17403). This region issue affects boxed closures as well.
Closes issue #17780- Loading branch information
Showing
9 changed files
with
135 additions
and
36 deletions.
There are no files selected for viewing
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,50 @@ | ||
| // 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. | ||
|
|
||
| #![feature(unboxed_closures, overloaded_calls)] | ||
|
|
||
| fn set(x: &mut uint) { *x = 5; } | ||
|
|
||
| fn main() { | ||
| // By-ref captures | ||
| { | ||
| let mut x = 0u; | ||
| let _f = |&:| x = 42; | ||
| //~^ ERROR cannot assign to data in a free | ||
| // variable from an immutable unboxed closure | ||
|
|
||
| let mut y = 0u; | ||
| let _g = |&:| set(&mut y); | ||
| //~^ ERROR cannot borrow data mutably in a free | ||
| // variable from an immutable unboxed closure | ||
|
|
||
| let mut z = 0u; | ||
| let _h = |&mut:| { set(&mut z); |&:| z = 42; }; | ||
| //~^ ERROR cannot assign to data in a | ||
| // free variable from an immutable unboxed closure | ||
| } | ||
| // By-value captures | ||
| { | ||
| let mut x = 0u; | ||
| let _f = move |&:| x = 42; | ||
| //~^ ERROR cannot assign to data in a free | ||
| // variable from an immutable unboxed closure | ||
|
|
||
| let mut y = 0u; | ||
| let _g = move |&:| set(&mut y); | ||
| //~^ ERROR cannot borrow data mutably in a free | ||
| // variable from an immutable unboxed closure | ||
|
|
||
| let mut z = 0u; | ||
| let _h = move |&mut:| { set(&mut z); move |&:| z = 42; }; | ||
| //~^ ERROR cannot assign to data in a free | ||
| // variable from an immutable unboxed closure | ||
| } | ||
| } |
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters