syntax_data: {"ast_node_type":"other","tokens":[{"end":78,"kind":"keyword","start":0,"text":"//"}]}
source_snippet:     // the operations that involve the mutation, i.e. within the `borrow_mut`.
context_before:     // reason for the `Formatter`/`BlockFormatter` split; `BlockFormatter` has
context_after:     analysis: RefCell<&'mir mut A>,