/// because we sometimes need to use SimplifiedTypeGen values as stable sorting
/// keys (in which case we use a DefPathHash as id-type) but in the general case
/// the non-stable but fast to construct DefId-version is the better choice.
-#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash, PartialOrd, Ord, RustcEncodable, RustcDecodable)]
+#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash, PartialOrd, Ord, TyEncodable, TyDecodable)]
pub enum SimplifiedTypeGen<D>
where
D: Copy + Debug + Ord + Eq,