syntax_data: {"ast_node_type":"variable","tokens":[{"end":75,"kind":"keyword","start":0,"text":"if"}]}
source_snippet:                 if let DefKind::TyAlias = self.collector.tcx.def_kind(id) {
context_before:                 let id = id.owner_id.def_id;
context_after:                     let items = self.collector.tcx.opaque_types_defined_by(id);