syntax_data: {"ast_node_type":"other","tokens":[{"end":86,"kind":"keyword","start":0,"text":"if"}]}
source_snippet:         if self.default_mode_span.is_none_or(|(_, old_mutbl)| min_mutbl < old_mutbl) {
context_before:         let min_mutbl = implicit_deref_mutbls.min().unwrap();
context_after:             // This changes the default binding mode to `ref` or `ref mut`. Return the old mode so