{"ast_node_type":"variable","tokens":[{"end":77,"kind":"keyword","start":0,"text":"let"}]}
            let ty = PlaceRef::ty(&place_base, self.body, self.infcx.tcx).ty;
            // using a type annotation in the closure argument instead leads to a lifetime error.
            ty.ty_adt_def().filter(|adt| adt.is_union()).map(|_| ty)