pub trait InferCtxtBuilderExt<'tcx> {
fn enter_canonical_trait_query<K, R>(
&mut self,
canonical_key: &Canonical<'tcx, K>,
operation: impl FnOnce(&ObligationCtxt<'_, 'tcx>, K) -> Fallible<R>
) -> Fallible<CanonicalizedQueryResponse<'tcx, R>>
where
K: TypeFoldable<'tcx>,
R: Debug + TypeFoldable<'tcx>,
Canonical<'tcx, QueryResponse<'tcx, R>>: ArenaAllocatable<'tcx>;
}