Specifying a Rust Toolchain
By default, Render uses the latest stable Rust toolchain, but you can specify a different toolchain by adding a file called
rust-toolchain at the root of your repo. It should contain a single line specifying the version. For example:
You can also use the
RUSTUP_TOOLCHAIN environment variable and set the value to a valid version. The environment variables overrides the version in toolchain files.
cargo +nightly...the specified toolchain must already be installed. You can install new toolchains using `rustup` as part of your build command.
Learn more about specifying a Rust toolchain.