Announce Rust 1.92 stable release

content/Rust-1.92.0.md

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+path = "2025/12/11/Rust-1.92.0"
+title = "Announcing Rust 1.92.0"
+authors = ["The Rust Release Team"]
+aliases = ["releases/1.92.0"]
+
+[extra]
+release = true
++++
+
+The Rust team is happy to announce a new version of Rust, 1.92.0. Rust is a programming language empowering everyone to build reliable and efficient software.
+
+If you have a previous version of Rust installed via `rustup`, you can get 1.92.0 with:
+
+```console
+$ rustup update stable
+```
+
+If you don't have it already, you can [get `rustup`](https://www.rust-lang.org/install.html) from the appropriate page on our website, and check out the [detailed release notes for 1.92.0](https://doc.rust-lang.org/stable/releases.html#version-1920-2025-12-11).
+
+If you'd like to help us out by testing future releases, you might consider updating locally to use the beta channel (`rustup default beta`) or the nightly channel (`rustup default nightly`). Please [report](https://github.com/rust-lang/rust/issues/new/choose) any bugs you might come across!
+
+## What's in 1.92.0 stable
+
+### Deny-by-default never type lints
+
+The language and compiler teams continue to work on stabilization of the [never type](https://doc.rust-lang.org/stable/std/primitive.never.html). In this release the [`never_type_fallback_flowing_into_unsafe`](https://doc.rust-lang.org/beta/rustc/lints/listing/deny-by-default.html#dependency-on-unit-never-type-fallback) and [`dependency_on_unit_never_type_fallback`](https://doc.rust-lang.org/beta/rustc/lints/listing/deny-by-default.html#dependency-on-unit-never-type-fallback) future compatibility lints were made deny-by-default, meaning they will cause a compilation error when detected.
+
+It's worth noting that while this can result in compilation errors, it is still a *lint;* these lints can all be `#[allow]`ed. These lints also will only fire when building the affected crates directly, not when they are built as dependencies (though a warning will be reported by Cargo in such cases).
+
+These lints detect code which is likely to be broken by the never type stabilization. It is highly advised to fix them if they are reported in your crate graph.
+
+We believe there to be approximately 500 crates affected by this lint. Despite that, we believe this to be acceptable, as lints are not a breaking change and it will allow for stabilizing the never type in the future. For more in-depth justification, the Language Team's assessment can be read here: [rust-lang/rust#146167#issuecomment-3363795006](https://github.com/rust-lang/rust/pull/146167#issuecomment-3363795006).
+
+### `unused_must_use` no longer warns about `Result<(), UninhabitedType>`
+
+Rust's `unused_must_use` lint warns when ignoring the return value of a function, if the function or its return type is annotated with `#[must_use]`. For instance, this warns if ignoring a return type of `Result`, to remind you to use `?`, or something like `.expect("...")`.
+
+However, some functions return `Result`, but the error type they use is not actually "inhabited", meaning it can never exist in real code (e.g. the [`!`](https://doc.rust-lang.org/std/primitive.never.html) or [`Infallible`](https://doc.rust-lang.org/std/convert/enum.Infallible.html) types).
+
+The `unused_must_use` lint now no longer warns on `Result<(), UninhabitedType>`, or on `ControlFlow<UninhabitedType, ()>`. For instance, it will not warn on `Result<(), Infallible>`. This avoids having to check for an error that can never happen.
+
+```rust
+use core::convert::Infallible;
+fn can_never_fail() -> Result<(), Infallible> {
+    // ...
+    Ok(())
+}
+
+fn main() {
+    can_never_fail();
+}
+```
+
+This is particularly useful with the common pattern of a trait with an associated error type, where the error type may *sometimes* be infallible:
+
+```rust
+trait UsesAssocErrorType {
+    type Error;
+    fn method(&self) -> Result<(), Self::Error>;
+}
+
+struct CannotFail;
+impl UsesAssocErrorType for CannotFail {
+    type Error = core::convert::Infallible;
+    fn method(&self) -> Result<(), Self::Error> {
+        Ok(())
+    }
+}
+
+struct CanFail;
+impl UsesAssocErrorType for CanFail {
+    type Error = std::io::Error;
+    fn method(&self) -> Result<(), Self::Error> {
+        Err(std::io::Error::other("something went wrong"))
+    }
+}
+
+fn main() {
+    CannotFail.method(); // No warning
+    CanFail.method(); // Warning: unused `Result` that must be used
+}
+```
+
+### Emit unwind tables even when `-Cpanic=abort` is enabled on linux
+
+Backtraces with `-Cpanic=abort` previously worked in Rust 1.22 but were broken in Rust 1.23, as we stopped emitting unwind tables with `-Cpanic=abort`. In Rust 1.45 a workaround in the form of `-Cforce-unwind-tables=yes` was stabilized.
+
+In Rust 1.92 unwind tables will be emitted by default even when `-Cpanic=abort` is specified, allowing for backtraces to work properly. If unwind tables are not desired then users should use `-Cforce-unwind-tables=no` to explicitly disable them being emitted.
+
+### Validate input to `#[macro_export]`
+
+Over the past few releases, many changes were made to the way built-in attributes are processed in the compiler. This should greatly improve the error messages and warnings Rust gives for built-in attributes and especially make these diagnostics more consistent among all of the over 100 built-in attributes.
+
+To give a small example, in this release specifically, Rust became stricter in checking what arguments are allowed to `macro_export` by [upgrading that check to a "deny-by-default lint" that will be reported in dependencies](https://github.com/rust-lang/rust/pull/143857). 
+
+### Stabilized APIs
+
+- [`NonZero<u{N}>::div_ceil`](https://doc.rust-lang.org/stable/std/num/struct.NonZero.html#method.div_ceil)
+- [`Location::file_as_c_str`](https://doc.rust-lang.org/stable/std/panic/struct.Location.html#method.file_as_c_str)
+- [`RwLockWriteGuard::downgrade`](https://doc.rust-lang.org/stable/std/sync/struct.RwLockWriteGuard.html#method.downgrade)
+- [`Box::new_zeroed`](https://doc.rust-lang.org/stable/std/boxed/struct.Box.html#method.new_zeroed)
+- [`Box::new_zeroed_slice`](https://doc.rust-lang.org/stable/std/boxed/struct.Box.html#method.new_zeroed_slice)
+- [`Rc::new_zeroed`](https://doc.rust-lang.org/stable/std/rc/struct.Rc.html#method.new_zeroed)
+- [`Rc::new_zeroed_slice`](https://doc.rust-lang.org/stable/std/rc/struct.Rc.html#method.new_zeroed_slice)
+- [`Arc::new_zeroed`](https://doc.rust-lang.org/stable/std/sync/struct.Arc.html#method.new_zeroed)
+- [`Arc::new_zeroed_slice`](https://doc.rust-lang.org/stable/std/sync/struct.Arc.html#method.new_zeroed_slice)
+- [`btree_map::Entry::insert_entry`](https://doc.rust-lang.org/stable/std/collections/btree_map/enum.Entry.html#method.insert_entry)
+- [`btree_map::VacantEntry::insert_entry`](https://doc.rust-lang.org/stable/std/collections/btree_map/struct.VacantEntry.html#method.insert_entry)
+- [`impl Extend<proc_macro::Group> for proc_macro::TokenStream`](https://doc.rust-lang.org/stable/proc_macro/struct.TokenStream.html#impl-Extend%3CGroup%3E-for-TokenStream)
+- [`impl Extend<proc_macro::Literal> for proc_macro::TokenStream`](https://doc.rust-lang.org/stable/proc_macro/struct.TokenStream.html#impl-Extend%3CLiteral%3E-for-TokenStream)
+- [`impl Extend<proc_macro::Punct> for proc_macro::TokenStream`](https://doc.rust-lang.org/stable/proc_macro/struct.TokenStream.html#impl-Extend%3CPunct%3E-for-TokenStream)
+- [`impl Extend<proc_macro::Ident> for proc_macro::TokenStream`](https://doc.rust-lang.org/stable/proc_macro/struct.TokenStream.html#impl-Extend%3CIdent%3E-for-TokenStream)
+
+These previously stable APIs are now stable in const contexts:
+
+- [`<[_]>::rotate_left`](https://doc.rust-lang.org/stable/std/primitive.slice.html#method.rotate_left)
+- [`<[_]>::rotate_right`](https://doc.rust-lang.org/stable/std/primitive.slice.html#method.rotate_right)
+
+### Other changes
+
+Check out everything that changed in [Rust](https://github.com/rust-lang/rust/releases/tag/1.92.0), [Cargo](https://doc.rust-lang.org/nightly/cargo/CHANGELOG.html#cargo-192-2025-12-11), and [Clippy](https://github.com/rust-lang/rust-clippy/blob/master/CHANGELOG.md#rust-192).
+
+## Contributors to 1.92.0
+
+Many people came together to create Rust 1.92.0. We couldn't have done it without all of you. [Thanks!](https://thanks.rust-lang.org/rust/1.92.0/)
+
+[platform-support]: https://doc.rust-lang.org/rustc/platform-support.html