a675778cfb
Add lint for holding RefCell Ref across an await Fixes #6008 This introduces the lint await_holding_refcell_ref. For async functions, we iterate over all types in generator_interior_types and look for `core::cell::Ref` or `core::cell::RefMut`. If we find one then we emit a lint. Heavily cribs from: https://github.com/rust-lang/rust-clippy/pull/5439 changelog: introduce the await_holding_refcell_ref lint