syntax_data: {"ast_node_type":"variable","tokens":[{"end":53,"kind":"keyword","start":0,"text":"let"}]}
source_snippet:         let base_fake_borrow_temps = &mut Vec::new();
context_before:     ) -> BlockAnd<PlaceBuilder<'tcx>> {
context_after:         let is_outermost_index = fake_borrow_temps.is_none();