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Summary: Rust 1.88.0 Release (June 26, 2025)

🚀 Installation

• Update via rustup update stable.
• Switch to beta/nightly using rustup default beta|nightly.

🔧 Key Features in 1.88.0

Let Chains (Rust 2024 Edition Only)

• Allows chaining of let statements with && in if and while.
• Supports both refutable and irrefutable patterns.
• Improves readability by reducing nesting.

if let A(x) = some_func() && let B(y) = x && y > 0 { ... }

Naked Functions

• Define low-level functions without compiler-generated prologue/epilogue.
• Use #[unsafe(naked)] and naked_asm! block for full control.

#[unsafe(naked)]
pub unsafe extern "sysv64" fn f(a: u64, b: u64) -> u64 {
    core::arch::naked_asm!("lea rax, [rdi + rsi]", "ret");
}

Boolean Configuration in cfg

• Now supports cfg(true) and cfg(false) for clearer conditional compilation.
• Replaces prior use of cfg(all()) or cfg(any()) for unconditional flags.

Cargo Cache Auto-Cleanup

• Cargo now garbage-collects unused cached crates:
  • Downloaded files: deleted after 3 months of inactivity.
  • Local files: deleted after 1 month.
• Behavior adjustable via cache.auto-clean-frequency.

✅ Stabilized APIs

New Stable APIs

• Cell::update, HashMap::extract_if, hint::select_unpredictable, and more.

Now Const-Stable

• NonNull<T>::replace, std::ptr::swap_nonoverlapping, Cell methods, etc.

📉 Other Changes

• i686-pc-windows-gnu demoted to Tier 2 (still supported, less tested).

🙌 Contributors

• Rust 1.88.0 was made possible by numerous community contributions. Thank you!

For full details, check the Rust 1.88.0 release notes.