syntax_data: {"ast_node_type":"variable","tokens":[{"end":70,"kind":"keyword","start":0,"text":"let"}]}
source_snippet:         let layout = tcx.coroutine_layout(def_id, self.args).unwrap();
context_before:     ) -> impl Iterator<Item: Iterator<Item = Ty<'tcx>>> {
context_after:         layout.variant_fields.iter().map(move |variant| {