1.45.1 post

posts/2020-07-30-Rust-1.45.1.md

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+---
+layout: post
+title: "Announcing Rust 1.45.1"
+author: The Rust Release Team
+release: true
+---
+
+The Rust team is happy to announce a new version of Rust, 1.45.1. Rust is a
+programming language that is empowering everyone to build reliable and
+efficient software.
+
+If you have a previous version of Rust installed via rustup, getting Rust
+1.45.1 is as easy as:
+
+```console
+rustup update stable
+```
+
+If you don't have it already, you can [get `rustup`][install] from the
+appropriate page on our website, and check out the [detailed release notes for
+1.45.1][notes] on GitHub.
+
+[install]: https://www.rust-lang.org/install.html
+[notes]: https://github.com/rust-lang/rust/blob/master/RELEASES.md#version-1451-2020-07-30
+
+## What's in 1.45.1 stable
+
+1.45.1 contains a collection of fixes, including one soundness fix. All patches
+in 1.45.1 address bugs that affect only the 1.45.0 release; prior releases are
+not affected by the bugs fixed in this release.
+
+### Fix const propagation with references
+
+In Rust 1.45.0, `rustc`'s const propagation pass did not properly handle
+encountering references when determining whether to propagate a given constant,
+which could lead to incorrect behavior. Our releases are run through [crater],
+and we did not detect it, which helps us be fairly confident that this affects a
+very small set of code in the wild (if any).
+
+The conditions necessary to cause this bug are highly unlikely to occur in
+practice: the code must have inputs consisting of entirely constant values and
+no control flow or function calls in between.
+
+```rust
+struct Foo {
+    x: u32,
+}
+
+fn main() {
+    let mut foo = Foo { x: 42 };
+    let x = &mut foo.x;
+    *x = 13;
+    let y = foo;
+    println!("{}", y.x); // -> 42; expected result: 13
+}
+```
+
+## Contributors to 1.45.1
+
+Many people came together to create Rust 1.45.1. We couldn't have done it
+without all of you. [Thanks!](https://thanks.rust-lang.org/rust/1.45.1/)
+
+[crater]: https://github.com/rust-lang/crater