{"ast_node_type":"variable","tokens":[{"end":81,"kind":"keyword","start":0,"text":"let"}]}
                let vtable_entries = self.vtable_entries(data_a.principal(), ty);
                    self.tcx.supertrait_vtable_slot((src_pointee_ty, dest_pointee_ty));
                if let Some(entry_idx) = vptr_entry_idx {