{"ast_node_type":"variable","tokens":[{"end":73,"kind":"keyword","start":0,"text":"let"}]}
                        let inner_ty = match args[0].expect_ty().kind() {
                    ty::Adt(pin, args) if self.tcx.is_lang_item(pin.did(), hir::LangItem::Pin) => {
                            ty::Ref(_, ty, _) => *ty,