diff --git a/mono-traversable/mono-traversable.cabal b/mono-traversable/mono-traversable.cabal
index c8cad759..da954c6f 100644
--- a/mono-traversable/mono-traversable.cabal
+++ b/mono-traversable/mono-traversable.cabal
@@ -5,7 +5,7 @@ cabal-version: 1.12
 -- see: https://github.com/sol/hpack
 
 name:           mono-traversable
-version:        1.0.17.0
+version:        1.0.17.1
 synopsis:       Type classes for mapping, folding, and traversing monomorphic containers
 description:    Please see the README at <https://www.stackage.org/package/mono-traversable>
 category:       Data
diff --git a/mono-traversable/package.yaml b/mono-traversable/package.yaml
index bae7facd..0c7ff52e 100644
--- a/mono-traversable/package.yaml
+++ b/mono-traversable/package.yaml
@@ -1,5 +1,5 @@
 name:        mono-traversable
-version:     1.0.17.0
+version:     1.0.17.1
 synopsis:    Type classes for mapping, folding, and traversing monomorphic containers
 description: Please see the README at <https://www.stackage.org/package/mono-traversable>
 category:    Data
diff --git a/mono-traversable/src/Data/Containers.hs b/mono-traversable/src/Data/Containers.hs
index 6b4ac042..31322e8a 100644
--- a/mono-traversable/src/Data/Containers.hs
+++ b/mono-traversable/src/Data/Containers.hs
@@ -4,6 +4,7 @@
 {-# LANGUAGE TypeFamilies #-}
 {-# LANGUAGE MultiParamTypeClasses #-}
 {-# LANGUAGE CPP #-}
+{-# LANGUAGE TypeOperators #-}
 -- | Warning: This module should be considered highly experimental.
 module Data.Containers where
 
diff --git a/mono-traversable/src/Data/MonoTraversable/Unprefixed.hs b/mono-traversable/src/Data/MonoTraversable/Unprefixed.hs
index 326ee27d..9318deb4 100644
--- a/mono-traversable/src/Data/MonoTraversable/Unprefixed.hs
+++ b/mono-traversable/src/Data/MonoTraversable/Unprefixed.hs
@@ -1,6 +1,7 @@
 {-# LANGUAGE CPP #-}
 {-# LANGUAGE FlexibleContexts #-}
 {-# LANGUAGE TypeFamilies #-}
+{-# LANGUAGE TypeOperators #-}
 -- | The functions in "Data.MonoTraversable" are all prefixed with the letter
 -- @o@ to avoid conflicts with their polymorphic counterparts. This module
 -- exports the same identifiers without the prefix, for all cases where the
diff --git a/mono-traversable/src/Data/Sequences.hs b/mono-traversable/src/Data/Sequences.hs
index e6d05038..2d82ee60 100644
--- a/mono-traversable/src/Data/Sequences.hs
+++ b/mono-traversable/src/Data/Sequences.hs
@@ -5,6 +5,7 @@
 {-# LANGUAGE ConstraintKinds #-}
 {-# LANGUAGE MultiParamTypeClasses #-}
 {-# LANGUAGE FunctionalDependencies #-}
+{-# LANGUAGE TypeOperators #-}
 -- | Abstractions over sequential data structures, like lists and vectors.
 module Data.Sequences where
 
diff --git a/mutable-containers/bench/deque.hs b/mutable-containers/bench/deque.hs
index 41e116e6..117adb0e 100644
--- a/mutable-containers/bench/deque.hs
+++ b/mutable-containers/bench/deque.hs
@@ -1,5 +1,6 @@
 {-# LANGUAGE ConstraintKinds #-}
 {-# LANGUAGE TypeFamilies    #-}
+{-# LANGUAGE TypeOperators #-}
 import Control.Monad
 import Gauge.Main
 import Data.Mutable
diff --git a/mutable-containers/bench/ref.hs b/mutable-containers/bench/ref.hs
index ee0fff0d..a78b8f11 100644
--- a/mutable-containers/bench/ref.hs
+++ b/mutable-containers/bench/ref.hs
@@ -1,4 +1,5 @@
 {-# LANGUAGE TypeFamilies #-}
+{-# LANGUAGE TypeOperators #-}
 import Control.Monad
 import Gauge.Main
 import Data.Mutable
diff --git a/mutable-containers/mutable-containers.cabal b/mutable-containers/mutable-containers.cabal
index ce4f5ae7..2cd3d339 100644
--- a/mutable-containers/mutable-containers.cabal
+++ b/mutable-containers/mutable-containers.cabal
@@ -5,7 +5,7 @@ cabal-version: 1.12
 -- see: https://github.com/sol/hpack
 
 name:           mutable-containers
-version:        0.3.4.1
+version:        0.3.4.2
 synopsis:       Abstractions and concrete implementations of mutable containers
 description:    See docs and README at <http://www.stackage.org/package/mutable-containers>
 category:       Data
diff --git a/mutable-containers/package.yaml b/mutable-containers/package.yaml
index c007e8c6..331327b5 100644
--- a/mutable-containers/package.yaml
+++ b/mutable-containers/package.yaml
@@ -1,5 +1,5 @@
 name:        mutable-containers
-version:     0.3.4.1
+version:     0.3.4.2
 synopsis:    Abstractions and concrete implementations of mutable containers
 description: See docs and README at <http://www.stackage.org/package/mutable-containers>
 category:    Data
diff --git a/mutable-containers/src/Data/Mutable/Class.hs b/mutable-containers/src/Data/Mutable/Class.hs
index 8f05f2e5..67686c11 100644
--- a/mutable-containers/src/Data/Mutable/Class.hs
+++ b/mutable-containers/src/Data/Mutable/Class.hs
@@ -2,6 +2,7 @@
 {-# LANGUAGE FlexibleContexts  #-}
 {-# LANGUAGE FlexibleInstances #-}
 {-# LANGUAGE TypeFamilies      #-}
+{-# LANGUAGE TypeOperators #-}
 -- | Various typeclasses for mutable containers.
 module Data.Mutable.Class
     ( PrimMonad
diff --git a/mutable-containers/test/Spec.hs b/mutable-containers/test/Spec.hs
index 53cb6cc3..9ae4eaad 100644
--- a/mutable-containers/test/Spec.hs
+++ b/mutable-containers/test/Spec.hs
@@ -1,5 +1,6 @@
 {-# LANGUAGE TypeFamilies #-}
 {-# LANGUAGE FlexibleContexts #-}
+{-# LANGUAGE TypeOperators #-}
 
 import Control.Monad             (forM_)
 import Data.Mutable