sccache/docs/Rust.md

sccache includes support for caching Rust compilation. This includes many caveats, and is primarily focused on caching rustc invocations as produced by cargo. A (possibly-incomplete) list follows:

• --emit is required.
• --crate-name is required.
• Only link and dep-info are supported as --emit values, and link must be present.
• --out-dir is required.
• -o file is not supported.
• Compilation from stdin is not supported, a source file must be provided.
• Values from env! require Rust >= 1.46 to be tracked in caching.
• Procedural macros that read files from the filesystem may not be cached properly
• Target specs aren't hashed (e.g. custom target specs)

If you are using Rust 1.18 or later, you can ask cargo to wrap all compilation with sccache by setting RUSTC_WRAPPER=sccache in your build environment.