Rust 1.64: What's New, Release History & Support Lifecycle

What Is New in Rust 1.64

How does the stabilized IntoFuture trait improve async code ergonomics?

IntoFuture lets you .await on any type that can be converted into a Future, removing the explicit .send() call.

In practice you can turn a builder that previously required:

let response = StorageRequest::new()
    .set_debug(true)
    .send()
    .await?;

into a single await step:

let response = StorageRequest::new()
    .set_debug(true)
    .await?;

This matters if you want a more fluent API without exposing the intermediate future type. Implementing IntoFuture does require a named future (often a boxed one) but future work on TAIT will make it lighter.

What C-compatible FFI types are now available in core and alloc?

core::ffi and alloc::ffi now expose the full set of c_* type aliases (e.g., c_uint, c_ulong) and CString utilities without pulling in std.

Example usage in a no-std environment:

use core::ffi::{c_int, CStr};

extern "C" {
    fn libc_function(arg: c_int) -> c_int;
}

alloc::ffi::CString can be used when you have an allocator but not the full standard library, simplifying embedded FFI code.

How can Cargo workspace inheritance and multi-target builds reduce duplication?

Cargo now lets you define common package metadata at the workspace level and pass multiple --target flags to build several binaries at once.

• Workspace inheritance: put shared fields like version, repository, or rust-version under [workspace.package] or [workspace.dependencies] to keep them in sync.
• Multi-target builds: run cargo build --target x86_64-unknown-linux-gnu --target aarch64-apple-darwin or set an array of targets in .cargo/config.toml under build.target.

This matters for teams maintaining libraries for both desktop and embedded platforms, as it eliminates repetitive Cargo.toml entries and enables a single CI step for all targets.

What tooling updates arrived via rustup in 1.64?

rust-analyzer is shipped as a rustup component, making installation and version management easier.

To add it run rustup component add rust-analyzer. The installed binary can be invoked with rustup run stable rust-analyzer. Future rustup releases will proxy the command so you can call rust-analyzer directly.

Most users will still prefer the upstream rust-analyzer releases for more frequent updates, but the rustup component ensures a baseline version is always available on supported platforms.