{"ast_node_type":"other","tokens":[{"end":60,"kind":"keyword","start":0,"text":"(FlatSet::Elem(left),"}]}
            (FlatSet::Elem(left), FlatSet::Elem(right)) => {
            // Both sides are known, do the actual computation.
                match self.ecx.binary_op(op, &left, &right).discard_err() {