Static rustc_lint::unused::UNUSED_PARENS[]

pub(super) static UNUSED_PARENS: &Lint = &::lint::Lint{name: "UNUSED_PARENS",
              default_level: ::lint::Warn,
              desc:
                  "`if`, `match`, `while` and `return` do not need parentheses",
              edition_lint_opts: 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?