In particular: - `unwrap_unchecked()` for `Option`. - `unwrap_unchecked()` and `unwrap_err_unchecked()` for `Result`. These complement other `*_unchecked()` methods in `core` etc. Currently there are a couple of places it may be used inside rustc (`LinkedList`, `BTree`). It is also easy to find other repositories with similar functionality. Fixes #48278. Signed-off-by: Miguel Ojeda <ojeda@kernel.org>