syntax_data: {"ast_node_type":"other","tokens":[{"end":99,"kind":"keyword","start":0,"text":"///"}]}
source_snippet: /// 4. The fake borrows may be of places in inactive variants, e.g. here we need to fake borrow `x`
context_before: ///    ```
context_after: ///    and `(x as Some).0`, but when we reach the guard `x` may not be `Some`.