{"ast_node_type":"variable","tokens":[{"end":71,"kind":"keyword","start":0,"text":"let"}]}
                let lhs_ty = self.typeck_results.node_type(lhs.hir_id);
            hir::ExprKind::Binary(ref op, lhs, rhs) => {
                let rhs_ty = self.typeck_results.node_type(rhs.hir_id);