{"ast_node_type":"import","tokens":[{"end":87,"kind":"keyword","start":0,"text":"//"}]}
            // use knowledge of built-in binary ops, which can sometimes help inference
        if self.is_builtin_binop(&lhs_ty, &rhs_ty, op) {
            let builtin_ret = self.enforce_builtin_binop_types(&lhs_ty, &rhs_ty, op);