From a691f6d8b70beed4cf2bb5f716b1e6d75ce788ed Mon Sep 17 00:00:00 2001
From: timofey <tim@ongoteam.yaconnect.com>
Date: Thu, 27 Apr 2023 04:50:49 +0000
Subject: [PATCH] CovariantFunctor for CompositionClass

---
 src/func/classes/composition.rs | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/src/func/classes/composition.rs b/src/func/classes/composition.rs
index fbcb62c..c614de7 100644
--- a/src/func/classes/composition.rs
+++ b/src/func/classes/composition.rs
@@ -166,3 +166,14 @@ impl<U: SharedFunctor + Functor, V: SharedFunctor> SharedFunctor for Composition
         U::fmap(V::unshare, U::unshare(sa))
     }
 }
+
+impl<U: CovariantFunctor + Functor, V: CovariantFunctor> CovariantFunctor
+    for CompositionClass<U, V>
+{
+    fn variate<'a: 'b, 'b, A: 'a>(fa: Self::F<'a, A>) -> Self::F<'b, A>
+    where
+        Self: 'a,
+    {
+        U::fmap(V::variate, U::variate(fa))
+    }
+}