make target an associated type

packages/generational-box/src/unsync.rs

@@ -92,7 +92,7 @@ impl AnyStorage for UnsyncStorage {
     type Ref<R: ?Sized + 'static> = GenerationalRef<Ref<'static, R>>;
     type Mut<W: ?Sized + 'static> = GenerationalRefMut<RefMut<'static, W>>;
 
-    fn try_map<I, U: ?Sized + 'static>(
+    fn try_map<I: ?Sized, U: ?Sized + 'static>(
         _self: Self::Ref<I>,
         f: impl FnOnce(&I) -> Option<&U>,
     ) -> Option<Self::Ref<U>> {