Toolchains

A Rust build in Bazel selects its compiler, standard library, and companion tools through a set of registered Bazel toolchains. rules_rust ships one toolchain type per companion tool so that Rust, rust-analyzer, and rustfmt can be resolved independently.

Most users register toolchains via the rust module extension (see Bzlmod) rather than declaring these rules directly. The rules below exist for users who need to define custom toolchains — for example, to point at a locally built rustc or to add a target triple that the extension doesn't cover.

Toolchain rules

• rust_toolchain — Declare a Rust compilation toolchain: the rustc binary, standard library, linker, and per-target compilation settings.
• rustfmt_toolchain — Declare a toolchain providing the rustfmt binary used by rustfmt rules.
• rust_analyzer_toolchain — Declare a toolchain providing the rust-analyzer binary and proc-macro server used by the rust_analyzer integration.

Data rules

• rust_stdlib_filegroup — Group the files of a Rust standard library archive into a target that can be attached to a rust_toolchain via the rust_std attribute.