syntax_data: {"ast_node_type":"variable","tokens":[{"end":60,"kind":"keyword","start":0,"text":"let"}]}
source_snippet:         let variances = cx.variances_of(self.def_id.into());
context_before:     pub fn iter_captured_args(self, cx: I) -> impl Iterator<Item = (usize, I::GenericArg)> {
context_after:         std::iter::zip(self.args.iter(), variances.iter()).enumerate().filter_map(