syntax_data: {"ast_node_type":"other","tokens":[{"end":29,"kind":"keyword","start":0,"text":"f(&new_value,"}]}
source_snippet:         f(&new_value, self)?;
context_before:         let (new_value, _) = self.name_all_regions(value, mode)?;
context_after:         self.region_index = old_region_index;