diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,8 @@
+# 1.0.1.0
+
+- Added `subsume` to `Control.Monad.Freer` for deduplicating effects.
+- Added `gets` to `Control.Monad.Freer.State` ([#1](https://github.com/lexi-lambda/freer-simple/pull/1)).
+
 # 1.0.0.0
 
 - Initial release.
diff --git a/freer-simple.cabal b/freer-simple.cabal
--- a/freer-simple.cabal
+++ b/freer-simple.cabal
@@ -1,9 +1,11 @@
--- This file has been generated from package.yaml by hpack version 0.18.1.
+-- This file has been generated from package.yaml by hpack version 0.20.0.
 --
 -- see: https://github.com/sol/hpack
+--
+-- hash: 1b33b14be04bebcd0fa94c86502cf8b40f41ecf708b33c723951b76d9ef4f017
 
 name:           freer-simple
-version:        1.0.0.0
+version:        1.0.1.0
 synopsis:       Implementation of a friendly effect system for Haskell.
 description:    An implementation of an effect system for Haskell (a fork of
                 <http://hackage.haskell.org/package/freer-effects freer-effects>), which is
@@ -43,8 +45,8 @@
   default-extensions: ConstraintKinds DataKinds DeriveFunctor FlexibleContexts FlexibleInstances FunctionalDependencies GADTs LambdaCase MultiParamTypeClasses RankNTypes ScopedTypeVariables TypeApplications TypeOperators
   ghc-options: -Wall -Wcompat -Wincomplete-record-updates -Wincomplete-uni-patterns -Wredundant-constraints
   build-depends:
-      base >= 4.9 && < 5
-    , natural-transformation >= 0.2
+      base >=4.9 && <5
+    , natural-transformation >=0.2
     , transformers-base
   exposed-modules:
       Control.Monad.Freer
@@ -71,7 +73,7 @@
   default-extensions: ConstraintKinds DataKinds DeriveFunctor FlexibleContexts FlexibleInstances FunctionalDependencies GADTs LambdaCase MultiParamTypeClasses RankNTypes ScopedTypeVariables TypeApplications TypeOperators
   ghc-options: -Wall -Wcompat -Wincomplete-record-updates -Wincomplete-uni-patterns -Wredundant-constraints
   build-depends:
-      base >= 4.9 && < 5
+      base >=4.9 && <5
     , freer-simple
   other-modules:
       Capitalize
@@ -79,6 +81,7 @@
       Coroutine
       Fresh
       Trace
+      Paths_freer_simple
   default-language: Haskell2010
 
 test-suite unit
@@ -89,8 +92,8 @@
   default-extensions: ConstraintKinds DataKinds DeriveFunctor FlexibleContexts FlexibleInstances FunctionalDependencies GADTs LambdaCase MultiParamTypeClasses RankNTypes ScopedTypeVariables TypeApplications TypeOperators
   ghc-options: -Wall -Wcompat -Wincomplete-record-updates -Wincomplete-uni-patterns -Wredundant-constraints
   build-depends:
-      base >= 4.9 && < 5
-    , QuickCheck
+      QuickCheck
+    , base >=4.9 && <5
     , freer-simple
     , tasty
     , tasty-hunit
@@ -103,6 +106,7 @@
       Tests.NonDet
       Tests.Reader
       Tests.State
+      Paths_freer_simple
   default-language: Haskell2010
 
 benchmark core
@@ -113,10 +117,12 @@
   default-extensions: ConstraintKinds DataKinds DeriveFunctor FlexibleContexts FlexibleInstances FunctionalDependencies GADTs LambdaCase MultiParamTypeClasses RankNTypes ScopedTypeVariables TypeApplications TypeOperators
   ghc-options: -Wall -Wcompat -Wincomplete-record-updates -Wincomplete-uni-patterns -Wredundant-constraints -O2
   build-depends:
-      base >= 4.9 && < 5
+      base >=4.9 && <5
     , criterion
-    , extensible-effects
+    , extensible-effects <2
     , free
     , freer-simple
     , mtl
+  other-modules:
+      Paths_freer_simple
   default-language: Haskell2010
diff --git a/src/Control/Monad/Freer.hs b/src/Control/Monad/Freer.hs
--- a/src/Control/Monad/Freer.hs
+++ b/src/Control/Monad/Freer.hs
@@ -217,6 +217,7 @@
     -- *** Basic effect handlers
   , interpret
   , interpose
+  , subsume
     -- *** Derived effect handlers
   , reinterpret
   , reinterpret2
@@ -264,6 +265,12 @@
 interpose :: forall eff effs. Member eff effs => (eff ~> Eff effs) -> Eff effs ~> Eff effs
 interpose f = interposeWith (\e -> (f e >>=))
 {-# INLINE interpose #-}
+
+-- | Interprets an effect in terms of another identical effect. This can be used
+-- to eliminate duplicate effects.
+subsume :: forall eff effs. Member eff effs => Eff (eff ': effs) ~> Eff effs
+subsume = interpret send
+{-# INLINE subsume #-}
 
 -- | Like 'interpret', but instead of removing the interpreted effect @f@,
 -- reencodes it in some new effect @g@.
diff --git a/src/Control/Monad/Freer/State.hs b/src/Control/Monad/Freer/State.hs
--- a/src/Control/Monad/Freer/State.hs
+++ b/src/Control/Monad/Freer/State.hs
@@ -27,6 +27,7 @@
   , get
   , put
   , modify
+  , gets
 
     -- * State Handlers
   , runState
@@ -60,6 +61,11 @@
 -- @(s -> s)@.
 modify :: forall s effs. Member (State s) effs => (s -> s) -> Eff effs ()
 modify f = fmap f get >>= put
+
+-- | Retrieve a specific component of the current state using the provided
+-- projection function.
+gets :: forall s a effs. Member (State s) effs => (s -> a) -> Eff effs a
+gets f = f <$> get
 
 -- | Handler for 'State' effects.
 runState :: forall s effs a. s -> Eff (State s ': effs) a -> Eff effs (a, s)
diff --git a/src/Data/OpenUnion/Internal.hs b/src/Data/OpenUnion/Internal.hs
--- a/src/Data/OpenUnion/Internal.hs
+++ b/src/Data/OpenUnion/Internal.hs
@@ -1,3 +1,4 @@
+{-# OPTIONS_GHC -Wno-redundant-constraints #-} -- Due to use of TypeError.
 {-# OPTIONS_HADDOCK not-home #-}
 
 {-# LANGUAGE AllowAmbiguousTypes #-}