Static rustc_lint::unused::UNUSED_ATTRIBUTES[]

pub static UNUSED_ATTRIBUTES: &Lint = &::lint::Lint{name: "UNUSED_ATTRIBUTES",
              default_level: ::lint::Warn,
              desc: "detects attributes that were not used by the compiler",
              edition_lint_opts: None,
              report_in_external_macro: false,}
🔬 This is a nightly-only experimental API. (rustc_private)

this crate is being loaded from the sysroot, an unstable location; did you mean to load this crate from crates.io via Cargo.toml instead?