{"ast_node_type":"variable","tokens":[{"end":67,"kind":"keyword","start":0,"text":"if"}]}
                        if let ty::Adt(def, args) = metadata.kind()
                        // `std::mem::uninitialized::<&dyn Trait>()`, for example.
                            && tcx.is_lang_item(def.did(), LangItem::DynMetadata)