diff --git a/effectful-core/src/Effectful/Provider.hs b/effectful-core/src/Effectful/Provider.hs
index ff8f342..f5c5145 100644
--- a/effectful-core/src/Effectful/Provider.hs
+++ b/effectful-core/src/Effectful/Provider.hs
@@ -125,8 +125,8 @@ type instance DispatchOf (Provider e input f) = Static NoSideEffects
 
 data instance StaticRep (Provider e input f) where
   Provider
-    :: !(Env providerEs)
-    -> !(forall r. HasCallStack => input -> Eff (e : providerEs) r -> Eff providerEs (f r))
+    :: !(Env handlerEs)
+    -> !(forall r. HasCallStack => input -> Eff (e : handlerEs) r -> Eff handlerEs (f r))
     -> StaticRep (Provider e input f)
 
 -- | Run the 'Provider' effect with a given effect handler.
@@ -171,8 +171,8 @@ provideWith
   -> Eff (e : es) a
   -> Eff es (f a)
 provideWith input action = unsafeEff $ \es -> do
-  Provider providerEs handler <- getEnv es
-  (`unEff` providerEs)
+  Provider handlerEs handler <- getEnv es
+  (`unEff` handlerEs)
     -- Corresponds to thawCallStack in runProvider.
     . withFrozenCallStack handler input
     . unsafeEff $ \eProviderEs -> do
@@ -195,17 +195,21 @@ provideWith_ input = adapt . provideWith input
 -- Helpers
 
 relinkProvider :: Relinker StaticRep (Provider e input f)
-relinkProvider = Relinker $ \relink (Provider providerEs run) -> do
-  newHandlerEs <- relink providerEs
+relinkProvider = Relinker $ \relink (Provider handlerEs run) -> do
+  newHandlerEs <- relink handlerEs
   pure $ Provider newHandlerEs run
 
-copyRef :: HasCallStack => Env (e : providerEs) -> Env es -> IO (Env (e : es))
+copyRef
+  :: HasCallStack
+  => Env (e : handlerEs)
+  -> Env es
+  -> IO (Env (e : es))
 copyRef (Env hoffset hrefs hstorage) (Env offset refs0 storage) = do
   when (hstorage /= storage) $ do
     error "storages do not match"
   let size = sizeofPrimArray refs0 - offset
   mrefs <- newPrimArray (size + 1)
-  copyPrimArray mrefs 0 hrefs hoffset 1
+  writePrimArray mrefs 0 $ indexPrimArray hrefs hoffset
   copyPrimArray mrefs 1 refs0 offset size
   refs <- unsafeFreezePrimArray mrefs
   pure $ Env 0 refs storage
diff --git a/effectful-core/src/Effectful/Provider/List.hs b/effectful-core/src/Effectful/Provider/List.hs
index 7e7add2..75b2140 100644
--- a/effectful-core/src/Effectful/Provider/List.hs
+++ b/effectful-core/src/Effectful/Provider/List.hs
@@ -38,31 +38,32 @@ import Effectful.Internal.Effect
 import Effectful.Internal.Env (Env(..))
 import Effectful.Internal.Utils
 
--- | Provide a way to run a handler of a @list@ of effects with a given @input@.
+-- | Provide a way to run a handler of multiple @providedEs@ with a given
+-- @input@.
 --
 -- /Note:/ @f@ can be used to alter the return type of the handler. If that's
 -- unnecessary, use 'ProviderList_'.
-data ProviderList (list :: [Effect]) (input :: Type) (f :: Type -> Type) :: Effect
+data ProviderList (providedEs :: [Effect]) (input :: Type) (f :: Type -> Type) :: Effect
 
 -- | A restricted variant of 'ProviderList' with unchanged return type of the
 -- handler.
-type ProviderList_ list input = ProviderList list input Identity
+type ProviderList_ providedEs input = ProviderList providedEs input Identity
 
-type instance DispatchOf (ProviderList list input f) = Static NoSideEffects
+type instance DispatchOf (ProviderList providedEs input f) = Static NoSideEffects
 
-data instance StaticRep (ProviderList list input f) where
+data instance StaticRep (ProviderList providedEs input f) where
   ProviderList
-    :: KnownEffects list
-    => !(Env providerEs)
-    -> !(forall r. HasCallStack => input -> Eff (list ++ providerEs) r -> Eff providerEs (f r))
-    -> StaticRep (ProviderList list input f)
+    :: KnownEffects providedEs
+    => !(Env handlerEs)
+    -> !(forall r. HasCallStack => input -> Eff (providedEs ++ handlerEs) r -> Eff handlerEs (f r))
+    -> StaticRep (ProviderList providedEs input f)
 
 -- | Run the 'ProviderList' effect with a given handler.
 runProviderList
-  :: (HasCallStack, KnownEffects list)
-  => (forall r. HasCallStack => input -> Eff (list ++ es) r -> Eff es (f r))
+  :: (HasCallStack, KnownEffects providedEs)
+  => (forall r. HasCallStack => input -> Eff (providedEs ++ es) r -> Eff es (f r))
   -- ^ The handler.
-  -> Eff (ProviderList list input f : es) a
+  -> Eff (ProviderList providedEs input f : es) a
   -> Eff es a
 runProviderList providerList m = unsafeEff $ \es0 -> do
   inlineBracket
@@ -77,55 +78,55 @@ runProviderList providerList m = unsafeEff $ \es0 -> do
 -- | Run the 'Provider' effect with a given handler that doesn't change its
 -- return type.
 runProviderList_
-  :: (HasCallStack, KnownEffects list)
-  => (forall r. HasCallStack => input -> Eff (list ++ es) r -> Eff es r)
+  :: (HasCallStack, KnownEffects providedEs)
+  => (forall r. HasCallStack => input -> Eff (providedEs ++ es) r -> Eff es r)
   -- ^ The handler.
-  -> Eff (ProviderList_ list input : es) a
+  -> Eff (ProviderList_ providedEs input : es) a
   -> Eff es a
 runProviderList_ providerList = runProviderList $ \input -> coerce . providerList input
 
 -- | Run the handler.
 provideList
-  :: forall list f es a
-   . (HasCallStack, ProviderList list () f :> es)
-  => Eff (list ++ es) a
+  :: forall providedEs f es a
+   . (HasCallStack, ProviderList providedEs () f :> es)
+  => Eff (providedEs ++ es) a
   -> Eff es (f a)
-provideList = provideListWith @list ()
+provideList = provideListWith @providedEs ()
 
 -- | Run the handler with unchanged return type.
 provideList_
-  :: forall list es a
-   . (HasCallStack, ProviderList_ list () :> es)
-  => Eff (list ++ es) a
+  :: forall providedEs es a
+   . (HasCallStack, ProviderList_ providedEs () :> es)
+  => Eff (providedEs ++ es) a
   -> Eff es a
-provideList_ = provideListWith_ @list ()
+provideList_ = provideListWith_ @providedEs ()
 
 -- | Run the handler with a given input.
 provideListWith
-  :: forall list input f es a
-   . (HasCallStack, ProviderList list input f :> es)
+  :: forall providedEs input f es a
+   . (HasCallStack, ProviderList providedEs input f :> es)
   => input
   -- ^ The input to the handler.
-  -> Eff (list ++ es) a
+  -> Eff (providedEs ++ es) a
   -> Eff es (f a)
 provideListWith input action = unsafeEff $ \es -> do
-  ProviderList (providerEs :: Env providerEs) providerList <- do
-    getEnv @(ProviderList list input f) es
-  (`unEff` providerEs)
+  ProviderList (handlerEs :: Env handlerEs) providerList <- do
+    getEnv @(ProviderList providedEs input f) es
+  (`unEff` handlerEs)
     -- Corresponds to a thawCallStack in runProviderList.
     . withFrozenCallStack providerList input
     . unsafeEff $ \eHandlerEs -> do
-    unEff action =<< copyRefs @list @providerEs eHandlerEs es
+    unEff action =<< copyRefs @providedEs @handlerEs eHandlerEs es
 
 -- | Run the handler that doesn't change its return type with a given input.
 provideListWith_
-  :: forall list input es a
-   . (HasCallStack, ProviderList_ list input :> es)
+  :: forall providedEs input es a
+   . (HasCallStack, ProviderList_ providedEs input :> es)
   => input
   -- ^ The input to the handler.
-  -> Eff (list ++ es) a
+  -> Eff (providedEs ++ es) a
   -> Eff es a
-provideListWith_ input = adapt . provideListWith @list input
+provideListWith_ input = adapt . provideListWith @providedEs input
   where
     adapt :: Eff es (Identity a) -> Eff es a
     adapt = coerce
@@ -134,23 +135,23 @@ provideListWith_ input = adapt . provideListWith @list input
 -- Helpers
 
 relinkProviderList :: Relinker StaticRep (ProviderList e input f)
-relinkProviderList = Relinker $ \relink (ProviderList providerEs run) -> do
-  newHandlerEs <- relink providerEs
+relinkProviderList = Relinker $ \relink (ProviderList handlerEs run) -> do
+  newHandlerEs <- relink handlerEs
   pure $ ProviderList newHandlerEs run
 
 copyRefs
-  :: forall list providerEs es
-   . (HasCallStack, KnownEffects list)
-  => Env (list ++ providerEs)
+  :: forall providedEs handlerEs es
+   . (HasCallStack, KnownEffects providedEs)
+  => Env (providedEs ++ handlerEs)
   -> Env es
-  -> IO (Env (list ++ es))
+  -> IO (Env (providedEs ++ es))
 copyRefs (Env hoffset hrefs hstorage) (Env offset refs0 storage) = do
   when (hstorage /= storage) $ do
     error "storages do not match"
-  let size = sizeofPrimArray refs0 - offset
-      listSize = knownEffectsLength @list
-  mrefs <- newPrimArray (size + listSize)
-  copyPrimArray mrefs 0 hrefs hoffset listSize
-  copyPrimArray mrefs listSize refs0 offset size
+  let providedEsSize = knownEffectsLength @providedEs
+      esSize = sizeofPrimArray refs0 - offset
+  mrefs <- newPrimArray (providedEsSize + esSize)
+  copyPrimArray mrefs 0 hrefs hoffset providedEsSize
+  copyPrimArray mrefs providedEsSize refs0 offset esSize
   refs <- unsafeFreezePrimArray mrefs
   pure $ Env 0 refs storage