diff --git a/LICENSE b/LICENSE
new file mode 100644
--- /dev/null
+++ b/LICENSE
@@ -0,0 +1,30 @@
+Copyright (c) 2017 Confer Health, Inc.
+
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+    * Redistributions of source code must retain the above copyright
+      notice, this list of conditions and the following disclaimer.
+
+    * Redistributions in binary form must reproduce the above
+      copyright notice, this list of conditions and the following
+      disclaimer in the documentation and/or other materials provided
+      with the distribution.
+
+    * Neither the name of Confer Health nor the names of other
+      contributors may be used to endorse or promote products derived
+      from this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
diff --git a/composite-base.cabal b/composite-base.cabal
--- a/composite-base.cabal
+++ b/composite-base.cabal
@@ -1,21 +1,16 @@
 cabal-version: 1.12
 
--- This file has been generated from package.yaml by hpack version 0.34.5.
---
--- see: https://github.com/sol/hpack
---
--- hash: 1bd1f66bd3d38d9ed108f5b7c2e4d437903998f82224fddeefae706b03de417d
-
 name:           composite-base
-version:        0.7.6.0
+version:        0.8.3.0
 synopsis:       Shared utilities for composite-* packages.
 description:    Shared helpers for the various composite packages.
 category:       Records
-homepage:       https://github.com/ConferOpenSource/composite#readme
+homepage:       https://github.com/composite-hs/composite-base#readme
 author:         Confer Health, Inc.
 maintainer:     oss@vitalbio.com
 copyright:      2017 Confer Health, Inc., 2020-2021 Vital Biosciences
 license:        BSD3
+license-file:   LICENSE
 build-type:     Simple
 
 library
@@ -58,13 +53,13 @@
       base >=4.12 && <5
     , deepseq ==1.4.*
     , exceptions >=0.8.3 && <0.11
-    , lens >=4.15.4 && <5.2
+    , lens >=4.15.4 && <5.3
     , monad-control >=1.0.2.2 && <1.1
-    , mtl >=2.2.1 && <2.3
+    , mtl >=2.2.1 && <2.4
     , profunctors >=5.2.1 && <5.7
-    , template-haskell >=2.11.1.0 && <2.19
-    , text >=1.2.2.2 && <1.3
-    , transformers >=0.5.2.0 && <0.6
+    , template-haskell >=2.11.1.0 && <2.22
+    , text >=1.2.2.2 && <2.1
+    , transformers >=0.5.2.0 && <0.7
     , transformers-base >=0.4.4 && <0.5
     , unliftio-core >=0.1.0.0 && <0.3.0.0
     , vinyl >=0.5.3 && <0.15
@@ -111,13 +106,13 @@
     , deepseq ==1.4.*
     , exceptions >=0.8.3 && <0.11
     , hspec
-    , lens >=4.15.4 && <5.2
+    , lens >=4.15.4 && <5.3
     , monad-control >=1.0.2.2 && <1.1
-    , mtl >=2.2.1 && <2.3
+    , mtl >=2.2.1 && <2.4
     , profunctors >=5.2.1 && <5.7
-    , template-haskell >=2.11.1.0 && <2.19
-    , text >=1.2.2.2 && <1.3
-    , transformers >=0.5.2.0 && <0.6
+    , template-haskell >=2.11.1.0 && <2.21
+    , text >=1.2.2.2 && <2.1
+    , transformers >=0.5.2.0 && <0.7
     , transformers-base >=0.4.4 && <0.5
     , unliftio-core >=0.1.0.0 && <0.3.0.0
     , vinyl >=0.5.3 && <0.15
diff --git a/src/Composite/CoRecord.hs b/src/Composite/CoRecord.hs
--- a/src/Composite/CoRecord.hs
+++ b/src/Composite/CoRecord.hs
@@ -5,21 +5,26 @@
 
 import Prelude
 import Composite.Record (AllHave, HasInstances, (:->)(getVal, Val), reifyDicts, reifyVal, val, zipRecsWith)
-import Control.Lens (Prism', prism')
+import Control.DeepSeq (NFData, rnf)
+import Control.Lens (Prism', Wrapped, Unwrapped, prism', review, view, _Wrapped')
+import Control.Monad.Except (ExceptT, throwError, withExceptT)
+import Data.Functor.Contravariant (Contravariant(contramap))
 import Data.Functor.Identity (Identity(Identity), runIdentity)
-import Data.Kind (Constraint)
+import Data.Kind (Constraint, Type)
 import Data.Maybe (fromMaybe)
 import Data.Profunctor (dimap)
 import Data.Proxy (Proxy(Proxy))
+import Data.Text (Text, pack)
 import Data.Vinyl.Core (Dict(Dict), Rec((:&), RNil), RMap, RecApplicative, RecordToList, ReifyConstraint, recordToList, reifyConstraint, rmap, rpure)
 import Data.Vinyl.Functor (Compose(Compose, getCompose), Const(Const), (:.))
 import Data.Vinyl.Lens (RElem, type (∈), type (⊆), rget, rput, rreplace)
 import Data.Vinyl.TypeLevel (RecAll, RIndex)
+import GHC.TypeLits (KnownSymbol, symbolVal)
 
 -- FIXME? replace with int-index/union or at least lift ideas from there. This encoding is awkward to work with and not compositional.
 
 -- |@CoRef f rs@ represents a single value of type @f r@ for some @r@ in @rs@.
-data CoRec :: (u -> *) -> [u] -> * where
+data CoRec :: (u -> Type) -> [u] -> Type where
   -- |Witness that @r@ is an element of @rs@ using '∈' ('RElem' with 'RIndex') from Vinyl.
   CoVal :: r ∈ rs => !(f r) -> CoRec f rs
 
@@ -37,6 +42,13 @@
       f (Compose (Dict a)) b = Const $ a == b
       toRec = reifyConstraint . fieldToRec
 
+instance forall rs. (AllHave '[NFData] rs, RecApplicative rs) => NFData (CoRec Identity rs) where
+  rnf (CoVal (Identity x)) = rnf' x
+    where
+      rnfer :: Rec (Op ()) rs
+      rnfer = reifyDicts (Proxy @'[NFData]) (\ _ -> Op rnf)
+      rnf' = runOp (rget rnfer)
+
 -- |The common case of a 'CoRec' with @f ~ 'Identity'@, i.e. a regular value.
 type Field = CoRec Identity
 
@@ -159,10 +171,10 @@
 
 -- |Given a list of constraints @cs@ required to apply some function, apply the function to whatever value @r@ (not @f r@) which the 'CoRec' contains.
 onCoRec
-  :: forall (cs :: [* -> Constraint]) (f :: * -> *) (rs :: [*]) (b :: *) (proxy :: [* -> Constraint] -> *).
+  :: forall (cs :: [Type -> Constraint]) (f :: Type -> Type) (rs :: [Type]) (b :: Type) (proxy :: [Type -> Constraint] -> Type).
      (AllHave cs rs, Functor f, RecApplicative rs)
   => proxy cs
-  -> (forall (a :: *). HasInstances a cs => a -> b)
+  -> (forall (a :: Type). HasInstances a cs => a -> b)
   -> CoRec f rs
   -> f b
 onCoRec p f (CoVal x) = go <$> x
@@ -172,10 +184,10 @@
 
 -- |Given a list of constraints @cs@ required to apply some function, apply the function to whatever value @r@ which the 'Field' contains.
 onField
-  :: forall (cs :: [* -> Constraint]) (rs :: [*]) (b :: *) (proxy :: [* -> Constraint] -> *).
+  :: forall (cs :: [Type -> Constraint]) (rs :: [Type]) (b :: Type) (proxy :: [Type -> Constraint] -> Type).
      (AllHave cs rs, RecApplicative rs)
   => proxy cs
-  -> (forall (a :: *). HasInstances a cs => a -> b)
+  -> (forall (a :: Type). HasInstances a cs => a -> b)
   -> Field rs
   -> b
 onField p f x = runIdentity (onCoRec p f x)
@@ -190,6 +202,9 @@
 -- |An extractor function @f a -> b@ which can be passed to 'foldCoRec' to eliminate one possible alternative of a 'CoRec'.
 newtype Case' f b a = Case' { unCase' :: f a -> b }
 
+instance Functor f => Contravariant (Case' f b) where
+  contramap f (Case' r) = Case' $ \x -> r (fmap f x) 
+
 -- |A record of @Case'@ eliminators for each @r@ in @rs@ representing the pieces of a total function from @'CoRec' f@ to @b@.
 type Cases' f rs b = Rec (Case' f b) rs
 
@@ -212,6 +227,10 @@
 {-# INLINE matchCoRec #-}
 
 newtype Case b a = Case { unCase :: a -> b }
+
+instance Contravariant (Case b) where
+  contramap f (Case r) = Case $ r . f
+
 type Cases rs b = Rec (Case b) rs
 
 -- |Fold a 'Field' using 'Cases' which eliminate each possible value held by the 'Field', yielding the @b@ produced by whichever case matches.
@@ -237,3 +256,64 @@
 widenField r =
   fromMaybe (error "widenField should be provably total, isn't") $
     firstField (rreplace (fieldToRec r) (rpure Nothing))
+
+-- |Constraint showing that @rs ⊆ ss@ and giving enough power to widen a @'CoRec' f rs@ to @'CoRec' f ss@.
+type WiderCoRec rs ss = (FoldRec ss ss, RecApplicative rs, RecApplicative ss, rs ⊆ ss)
+
+-- |Constraint on a pair of types @r@ and @s@ which are 'Wrapped' around @'CoRec' f rs@ and @'CoRec' f ss@ respectively and observes that those types can be unwrapped and the former can be widened to the latter.
+type WrappedWiderCoRec f r rs s ss = (Wrapped r, Unwrapped r ~ CoRec f rs, Wrapped s, Unwrapped s ~ CoRec f ss, WiderCoRec rs ss)
+
+-- |'WrappedWiderCoRec' specialized to 'CoRec' 'Identity', i.e. 'Field'.
+type WrappedWiderField r rs s ss = WrappedWiderCoRec Identity r rs s ss
+
+-- |Widen a @'CoRec' f rs@ wrapped in @r@ to a @'CoRec' f ss@ wrapped in @s@.
+widenWrappedCoRec :: WrappedWiderCoRec f r rs s ss => r -> s
+widenWrappedCoRec = review _Wrapped' . widenCoRec . view _Wrapped'
+
+-- |Widen a @'Field' rs@ wrapped in @r@ to a @'Field' ss@ wrapped in @s@.
+widenWrappedField :: WrappedWiderField r rs s ss => r -> s
+widenWrappedField = review _Wrapped' . widenCoRec . view _Wrapped'
+
+-- |Widen a wrapped 'CoRec' using 'widenWrappedCoRec' and then throw it as an 'ExceptT' error, as a convenience when using 'CoRec' / 'Field' for building up error types by set union.
+throwWidened :: (Monad m, WrappedWiderCoRec f e er e' er') => e -> ExceptT e' m a
+throwWidened = throwError . widenWrappedCoRec
+
+-- |Catch a wrapped 'CoRec' thrown by an 'ExceptT' and widen it using 'widenWrappedCoRec' then rethrow it, as a convenience when using 'CoRec' / 'Field' for building up error types by set union.
+rethrowWidened :: (Functor m, WrappedWiderCoRec f e er e' er') => ExceptT e m a -> ExceptT e' m a
+rethrowWidened = withExceptT widenWrappedCoRec
+
+-- |Specialized type of 'Case' for 'Val', with the type parameters in a convenient order for type application, e.g.:
+--
+-- @
+--   valCase @"foo" (\ a -> ...)
+--     :& valCase @"bar" (\ b -> ...)
+--     :& RNil
+-- @
+valCase :: forall s a b. (a -> b) -> Case b (s :-> a)
+valCase f = Case $ \(Val a) -> f a
+
+-- |Specialized type of 'Case'' for 'Val', with the type parameters in a convenient order for type application, e.g.:
+--
+-- @
+--   valCase' @"foo" (\ fa -> ...)
+--     :& valCase' @"bar" (\ fb -> ...)
+--     :& RNil
+-- @
+valCase' :: forall s f a b. Functor f => (f a -> b) -> Case' f b (s :-> a)
+valCase' f = Case' $ \fva -> f (fmap getVal fva)
+
+-- |Make a 'Case' which yields the symbol text for a field @s :-> ()@. E.g.:
+--
+-- @
+--   keywordCase @"foo" (Identity (Val ())) == "foo"
+-- @
+keywordCase :: KnownSymbol s => Case Text (s :-> ())
+keywordCase = keywordCase' id
+
+-- |Make a 'Case'' which yields the symbol text for a field @s :-> ()@ as projected through the given function. E.g.:
+--
+-- @
+--   keywordCase @"foo" (<> "bar") (Identity (Val ())) == "foobar"
+-- @
+keywordCase' :: KnownSymbol s => (Text -> a) -> Case a (s :-> ())
+keywordCase' f = Case $ \(Val () :: s :-> ()) -> f (pack (symbolVal (Proxy @s)))
diff --git a/src/Composite/Record.hs b/src/Composite/Record.hs
--- a/src/Composite/Record.hs
+++ b/src/Composite/Record.hs
@@ -10,21 +10,23 @@
   , ReifyNames(reifyNames)
   , RecWithContext(rmapWithContext)
   , RDelete, RDeletable, rdelete
+  , rwiden
+  , _SingleVal
   ) where
 
 import Control.DeepSeq(NFData(rnf))
 import Control.Lens (Iso, iso)
 import Control.Lens.TH (makeWrapped)
-import Data.Functor.Identity (Identity(Identity))
+import Data.Functor.Identity (Identity(Identity), runIdentity)
 import Data.Functor.Contravariant (Contravariant(contramap))
-import Data.Kind (Constraint)
+import Data.Kind (Constraint, Type)
 import Data.List.NonEmpty (NonEmpty((:|)))
 import Data.Proxy (Proxy(Proxy))
 import Data.String (IsString)
 import Data.Text (Text, pack)
-import Data.Vinyl (Rec((:&), RNil), RecApplicative, rcast, recordToList, rpure)
+import Data.Vinyl (Rec((:&), RNil), RecApplicative, RMap, rcast, rdowncast, recordToList, rmap, rpure)
 import qualified Data.Vinyl as Vinyl
-import Data.Vinyl.Functor (Compose(Compose), Const(Const), (:.))
+import Data.Vinyl.Functor (Compose(Compose, getCompose), Const(Const), (:.))
 import Data.Vinyl.Lens (type (∈), type (⊆))
 import qualified Data.Vinyl.TypeLevel as Vinyl
 import Data.Vinyl.XRec(IsoHKD(HKD, toHKD, unHKD))
@@ -80,20 +82,12 @@
   traverse k (Val a) = Val <$> k a
   {-# INLINE traverse #-}
 instance Monad ((:->) s) where
-  return = Val
-  {-# INLINE return #-}
   Val a >>= k = k a
   {-# INLINE (>>=) #-}
 
 instance NFData a => NFData (s :-> a) where
   rnf (Val x) = rnf x
 
-instance NFData (Record '[]) where
-  rnf RNil = ()
-
-instance (NFData x, NFData (Record xs)) => NFData (Record (x : xs)) where
-  rnf (x :& xs) = rnf x `seq` rnf xs
-
 instance forall (s :: Symbol) a. (KnownSymbol s, Show a) => Show (s :-> a) where
   showsPrec p (Val a) = ((symbolVal (Proxy :: Proxy s) ++ " :-> ") ++) . showsPrec p a
 
@@ -299,14 +293,14 @@
 -- |Given a list of constraints @cs@, apply some function for each @r@ in the target record type @rs@ with proof that those constraints hold for @r@,
 -- generating a record with the result of each application.
 reifyDicts
-  :: forall u. forall (cs :: [u -> Constraint]) (f :: u -> *) (rs :: [u]) (proxy :: [u -> Constraint] -> *).
+  :: forall u. forall (cs :: [u -> Constraint]) (f :: u -> Type) (rs :: [u]) (proxy :: [u -> Constraint] -> Type).
      (AllHave cs rs, RecApplicative rs)
   => proxy cs
   -> (forall proxy' (a :: u). HasInstances a cs => proxy' a -> f a)
   -> Rec f rs
 reifyDicts x f = go x (rpure (Const ())) f
   where
-    go :: forall (f :: u -> *) (cs :: [u -> Constraint]) (rs' :: [u]) (proxy :: [u -> Constraint] -> *). AllHave cs rs'
+    go :: forall (f :: u -> Type) (cs :: [u -> Constraint]) (rs' :: [u]) (proxy :: [u -> Constraint] -> Type). AllHave cs rs'
        => proxy cs
        -> Rec (Const ()) rs'
        -> (forall proxy' (a :: u). HasInstances a cs => proxy' a -> f a)
@@ -316,18 +310,18 @@
 {-# INLINE reifyDicts #-}
 
 -- |Class which reifies the symbols of a record composed of ':->' fields as 'Text'.
-class ReifyNames (rs :: [*]) where
+class ReifyNames (rs :: [Type]) where
   -- |Given a @'Rec' f rs@ where each @r@ in @rs@ is of the form @s ':->' a@, make a record which adds the 'Text' for each @s@.
   reifyNames :: Rec f rs -> Rec ((,) Text :. f) rs
 
 instance ReifyNames '[] where
   reifyNames _ = RNil
 
-instance forall (s :: Symbol) a (rs :: [*]). (KnownSymbol s, ReifyNames rs) => ReifyNames (s :-> a ': rs) where
+instance forall (s :: Symbol) a (rs :: [Type]). (KnownSymbol s, ReifyNames rs) => ReifyNames (s :-> a ': rs) where
   reifyNames (fa :& rs) = Compose ((,) (pack $ symbolVal (Proxy @s)) fa) :& reifyNames rs
 
 -- |Class with 'Data.Vinyl.rmap' but which gives the natural transformation evidence that the value its working over is contained within the overall record @ss@.
-class RecWithContext (ss :: [*]) (ts :: [*]) where
+class RecWithContext (ss :: [Type]) (ts :: [Type]) where
   -- |Apply a natural transformation from @f@ to @g@ to each field of the given record, except that the natural transformation can be mildly unnatural by having
   -- evidence that @r@ is in @ss@.
   rmapWithContext :: proxy ss -> (forall r. r ∈ ss => f r -> g r) -> Rec f ts -> Rec g ts
@@ -335,7 +329,7 @@
 instance RecWithContext ss '[] where
   rmapWithContext _ _ _ = RNil
 
-instance forall r (ss :: [*]) (ts :: [*]). (r ∈ ss, RecWithContext ss ts) => RecWithContext ss (r ': ts) where
+instance forall r (ss :: [Type]) (ts :: [Type]). (r ∈ ss, RecWithContext ss ts) => RecWithContext ss (r ': ts) where
   rmapWithContext proxy n (r :& rs) = n r :& rmapWithContext proxy n rs
 
 -- |Type function which removes the first element @r@ from a list @rs@, and doesn't expand if @r@ is not present in @rs@.
@@ -349,3 +343,14 @@
 -- |Remove an element @r@ from a @'Rec' f rs@. Note this is just a type constrained 'rcast'.
 rdelete :: RDeletable r rs => proxy r -> Rec f rs -> Rec f (RDelete r rs)
 rdelete _ = rcast
+
+-- |Widen a record from @'Record' rs@ to @'Rec' 'Maybe' ss@. Note this is just a type constrainted 'rdowncast'.
+rwiden :: (RecApplicative ss, RMap rs, RMap ss, rs ⊆ ss) => Record rs -> Rec Maybe ss
+rwiden = rmap (fmap runIdentity . getCompose) . rdowncast
+
+-- |'Iso' which observes that a record with a single field @s@ with value @a@ is isomorphic to the value alone.
+_SingleVal :: forall s a b. Iso (Record '[s :-> a]) (Record '[s :-> b]) a b
+_SingleVal =
+  let toA :: Record '[s :-> a] -> a = getVal . runIdentity . Vinyl.rget @(s :-> a)
+      fromA x = Identity (Val x) :& RNil
+   in iso toA fromA
diff --git a/src/Composite/TH.hs b/src/Composite/TH.hs
--- a/src/Composite/TH.hs
+++ b/src/Composite/TH.hs
@@ -22,6 +22,9 @@
 #if MIN_VERSION_template_haskell(2,17,0)
   , Specificity(SpecifiedSpec)
 #endif
+#if MIN_VERSION_template_haskell(2,21,0)
+  , BndrVis
+#endif
   )
 import Language.Haskell.TH.Lens (_TySynD)
 
@@ -146,11 +149,19 @@
 withOpticsAndProxies = withBoilerplate True True
 
 #if MIN_VERSION_template_haskell(2,17,0)
+#if MIN_VERSION_template_haskell(2,21,0)
+tyUnitToSpec :: Specificity -> TyVarBndr BndrVis -> TyVarBndr Specificity
+#else
 tyUnitToSpec :: Specificity -> TyVarBndr () -> TyVarBndr Specificity
-tyUnitToSpec x (PlainTV n ()) = PlainTV n x
-tyUnitToSpec x (KindedTV n () k) = KindedTV n x k
+#endif
+tyUnitToSpec x (PlainTV n _) = PlainTV n x
+tyUnitToSpec x (KindedTV n _ k) = KindedTV n x k
 
+#if MIN_VERSION_template_haskell(2,21,0)
+fieldDecUnitToSpec :: Specificity -> FieldDec BndrVis -> FieldDec Specificity
+#else
 fieldDecUnitToSpec :: Specificity -> FieldDec () -> FieldDec Specificity
+#endif
 fieldDecUnitToSpec x (FieldDec n b t v) = FieldDec n (map (tyUnitToSpec x) b) t v
 
 data FieldDec a = FieldDec
@@ -186,7 +197,9 @@
 #endif
   pure $ decs <> concat proxyDecs <> concat lensDecs <> concat prismDecs
 
-#if MIN_VERSION_template_haskell(2,17,0)
+#if MIN_VERSION_template_haskell(2,21,0)
+fieldDecMay :: (Name, [TyVarBndr BndrVis], Type) -> Maybe (FieldDec BndrVis)
+#elif MIN_VERSION_template_haskell(2,17,0)
 fieldDecMay :: (Name, [TyVarBndr ()], Type) -> Maybe (FieldDec ())
 #else
 fieldDecMay :: (Name, [TyVarBndr], Type) -> Maybe FieldDec
@@ -210,7 +223,9 @@
 prismNameFor = mkName . ("_" ++) . nameBase
 proxyNameFor = mkName . (++ "_") . over _head toLower . nameBase
 
-#if MIN_VERSION_template_haskell(2,17,0)
+#if MIN_VERSION_template_haskell(2,21,0)
+proxyDecFor :: FieldDec BndrVis -> Q [Dec]
+#elif MIN_VERSION_template_haskell(2,17,0)
 proxyDecFor :: FieldDec () -> Q [Dec]
 #else
 proxyDecFor :: FieldDec -> Q [Dec]
diff --git a/src/Control/Monad/Composite/Context.hs b/src/Control/Monad/Composite/Context.hs
--- a/src/Control/Monad/Composite/Context.hs
+++ b/src/Control/Monad/Composite/Context.hs
@@ -46,6 +46,7 @@
 import qualified Control.Monad.Writer.Lazy as Lazy
 import qualified Control.Monad.Writer.Strict as Strict
 import Control.Monad.Writer.Class (MonadWriter(writer, tell, listen, pass))
+import Data.Kind (Type)
 
 import Control.Monad.IO.Unlift
   ( MonadUnliftIO
@@ -59,7 +60,7 @@
 
 -- |Class of monad (stacks) which have context reading functionality baked in. Similar to 'Control.Monad.Reader.MonadReader' but can coexist with a
 -- another monad that provides 'Control.Monad.Reader.MonadReader' and requires the context to be a record.
-class Monad m => MonadContext (c :: [*]) m | m -> c where
+class Monad m => MonadContext (c :: [Type]) m | m -> c where
   -- |Fetch the context record from the environment.
   askContext :: m (Record c)
 
@@ -123,7 +124,7 @@
 askField l = asksContext $ view l
 
 -- |Monad transformer which adds an implicit environment which is a record. Isomorphic to @ReaderT (Record c) m@.
-newtype ContextT (c :: [*]) (m :: (* -> *)) a = ContextT { runContextT :: Record c -> m a }
+newtype ContextT (c :: [Type]) (m :: (Type -> Type)) a = ContextT { runContextT :: Record c -> m a }
 
 -- |Run some action in a given context, equivalent to 'runContextT' but with the arguments flipped.
 runInContext :: Record c -> ContextT c m a -> m a
diff --git a/test/RecordSpec.hs b/test/RecordSpec.hs
--- a/test/RecordSpec.hs
+++ b/test/RecordSpec.hs
@@ -1,3 +1,8 @@
+{-# LANGUAGE CPP #-}
+#if __GLASGOW_HASKELL__ >= 902
+{-# OPTIONS_GHC -Wno-incomplete-uni-patterns #-}
+#endif
+
 module RecordSpec where
 
 import Composite.Record