Cargo Features

rust_bundler_cp has no features set by default.

[dependencies]
rust_bundler_cp = { version = "0.3.16", features = ["inner_rustfmt"] }
inner_rustfmt = rustfmt-nightly

Features from optional dependencies

In crates that don't use the dep: syntax, optional dependencies automatically become Cargo features. These features may have been created by mistake, and this functionality may be removed in the future.

rustfmt-nightly inner_rustfmt?