syntax_data: {"ast_node_type":"other","tokens":[{"end":71,"kind":"keyword","start":0,"text":"expanded_cache:"}]}
source_snippet:     expanded_cache: FxHashMap<(DefId, GenericArgsRef<'tcx>), Ty<'tcx>>,
context_before:     // optimization for some large types produced by async fn trees.
context_after:     primary_def_id: Option<DefId>,