Rust Release Notes & Changelog

Language

• Add allow-by-default raw_borrows_via_references lint that checks for references that decay immediately into raw borrows
• Extend unconditional_panic lint to function calls that panic when the chunks/windows size is zero
• Stabilize C-variadic function definitions
• Stabilize the ability to use #[unsafe(naked)] functions to define C-variadic functions (#![feature(c_variadic_naked_functions)]).
• Trait methods are now resolved on an adjusted never type (producing a FCW)

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• rustc: fix miscompilation in generating vtables

Language

• Allow shortening lifetime of &mut when unsize-coercing, even in an invariant position. For example, you can now coerce a Cell<&'long mut i32> to a Cell<&'short mut dyn Send>. Such shortenings were already previously allowed when coercing a &mut to a &, or coercing a & to a &.
• Add deny-by-default invalid_runtime_symbol_definitions lint and warn-by-default suspicious_runtime_symbol_definitions lint
  • The lints currently specifically targets core runtime symbols like memcmp, memset, strlen, ... and is planned to be expanded in the next few releases.

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• rustc: Fix miscompilation in LLVM optimization This backports an LLVM submodule bump to include the LLVM-side fix and a revert of the rustc change that is one known trigger for the bug. The rustc side revert should not be strictly necessary but is done out of abundance of caution.

Language

• Consider Result<T, Uninhabited> and ControlFlow<Uninhabited, T> to be equivalent to T for must use lint
• Add allow-by-default dead_code_pub_in_binary lint for unused pub items in binary crates
• Stabilize the div32, lam-bh, lamcas, ld-seq-sa and scq target features
• Stabilize cfg(target_has_atomic_primitive_alignment)
• Allow trailing self in imports in more cases

Platform Support

• nvptx64-nvidia-cuda: drop support for old architectures and old ISAs

Refer to Rust's platform support page for more information on Rust's tiered platform support.

Stabilized APIs

• Default for RepeatN

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• Cargo: fix timeout/retry behavior
• Cargo: apply patches for CVE-2025-15661, CVE-2026-55199, and CVE-2026-55200 to libssh2
• rustc: fix miscompilation in MIR optimization

Language

• Allow passing expr metavariable to cfg
• Always coerce never types in tuple expressions
• Avoid incorrect inference guidance of function arguments in rare cases
• Support s390x vector registers in inline assembly
• Allow using constants of type ManuallyDrop as patterns (fixing a regression introduced in 1.94.0)

Compiler

• Enable link relaxation feature for LoongArch Linux targets
• Update riscv64gc-unknown-fuchsia baseline to RVA22 + vector

Libraries

• Support iterating over ranges of NonZero integers

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Language

• Stabilize if let guards on match arms
• irrefutable_let_patterns lint no longer lints on let chains
• Support importing path-segment keywords with renaming
• Stabilize inline assembly for PowerPC and PowerPC64
• const-eval: be more consistent in the behavior of padding during typed copies
• Const blocks are no longer evaluated to determine if expressions involving fallible operations can implicitly be constant-promoted.. Expressions whose ability to implicitly be promoted would depend on the result of a const block are no longer implicitly promoted.

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• Fix std::thread::spawn on wasm32-wasip1-threads
• Remove new methods added to std::os::windows::fs::OpenOptionsExt The new methods were unstable, but the trait itself is not sealed and so cannot be extended with non-default methods.
• Clippy: fix ICE in match_same_arms
• Cargo: update tar to 0.4.45 This resolves CVE-2026-33055 and CVE-2026-33056. Users of crates.io are not affected. See blog for more details.