Static rustc_lint::unused::UNUSED_IMPORT_BRACES[]

static UNUSED_IMPORT_BRACES: &Lint = &::lint::Lint{name: "UNUSED_IMPORT_BRACES",
              default_level: ::lint::Allow,
              desc: "unnecessary braces around an imported item",
              edition_deny: None,}
🔬 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?