syntax_data: {"ast_node_type":"other","tokens":[{"end":88,"kind":"keyword","start":0,"text":"relation.cx().mk_args_from_iter(iter::zip(a_arg.iter(),"}]}
source_snippet:     relation.cx().mk_args_from_iter(iter::zip(a_arg.iter(), b_arg.iter()).map(|(a, b)| {
context_before: ) -> RelateResult<I, I::GenericArgs> {
context_after:         relation.relate_with_variance(ty::Invariant, VarianceDiagInfo::default(), a, b)