{"ast_node_type":"other","tokens":[{"end":20,"kind":"keyword","start":0,"text":"//"}]}
            // here.
            // FIXME: dyn types may not have principal trait and we don't want to return auto trait
            TyKind::Dyn(dyn_ty) => dyn_ty.bounds.skip_binders().interned().first().and_then(|b| {