syntax_data: {"ast_node_type":"variable","tokens":[{"end":84,"kind":"keyword","start":0,"text":"if"}]}
source_snippet:         if let ty::Alias(ty::Opaque, ty::AliasTy { def_id, args, .. }) = *t.kind() {
context_before:     fn fold_ty(&mut self, t: Ty<'tcx>) -> Ty<'tcx> {
context_after:             self.expand_opaque_ty(def_id, args).unwrap_or(t)