diff --git a/circat.cabal b/circat.cabal
index cccd914..258ef55 100755
--- a/circat.cabal
+++ b/circat.cabal
@@ -47,6 +47,7 @@ Library
                     Circat.Shift
                     Circat.Mealy
                     Circat.Scan
+                    Circat.Doubli
                     Circat.Complex
                     Circat.FFT
                     Circat.Circuit
diff --git a/src/Circat/Circuit.hs b/src/Circat/Circuit.hs
index 09369cc..98e9eda 100644
--- a/src/Circat/Circuit.hs
+++ b/src/Circat/Circuit.hs
@@ -125,6 +125,7 @@ import TypeUnary.Vec hiding (get)
 
 -- TODO: Eliminate most of the following, as I move data types out of circat
 import Circat.Misc (Unit,(:*),(<~),Unop,Binop)
+import Circat.Doubli
 import Circat.Complex
 import Circat.Category
 import Circat.Classes
@@ -207,7 +208,7 @@ data Buses :: * -> * where
   BoolB   :: Source -> Buses Bool
   IntB    :: Source -> Buses Int
   FloatB  :: Source -> Buses Float
-  DoubleB :: Source -> Buses Double
+  DoubleB :: Source -> Buses Doubli
   PairB   :: Buses a -> Buses b -> Buses (a :* b)
   FunB    :: (a :> b) -> Buses (a -> b)
   IsoB    :: Buses (Rep a) -> Buses a
@@ -298,7 +299,7 @@ instance GenBuses Float  where
   delay = primDelay
   ty = const FloatT
 
-instance GenBuses Double  where
+instance GenBuses Doubli  where
   genBuses' = genBus DoubleB 64
   delay = primDelay
   ty = const DoubleT
@@ -334,9 +335,15 @@ isoErr nm = error (nm ++ ": IsoB")
 pairB :: Buses a :* Buses b -> Buses (a :* b)
 pairB (a,b) = PairB a b
 
+-- Workaround for "spurious non-exhaustive warning with GADT and newtypes"
+-- <https://ghc.haskell.org/trac/ghc/ticket/6124>.
+#define BogusMatch(name) name _ = error "BogusMatch"
+#define BogusAlt _ -> error "BogusMatch"
+
 unUnitB :: Buses Unit -> Unit
 unUnitB UnitB    = ()
 unUnitB (IsoB _) = isoErr "unUnitB"
+BogusMatch(unUnitB)
 
 unPairB :: Buses (a :* b) -> Buses a :* Buses b
 #if 0
@@ -346,14 +353,14 @@ unPairB (IsoB _)    = isoErr "unPairB"
 -- Lazier
 unPairB w = (a,b)
  where
-
    a = case w of
          PairB p _ -> p
          IsoB _    -> isoErr "unPairB"
+         BogusAlt
    b = case w of
          PairB _ q -> q
          IsoB _    -> isoErr "unPairB"
-
+         BogusAlt
 --    (a,b) = case w of
 --              PairB p q -> (p,q)
 --              IsoB _    -> isoErr "unPairB"
@@ -363,6 +370,7 @@ unPairB w = (a,b)
 unFunB :: Buses (a -> b) -> (a :> b)
 unFunB (FunB circ) = circ
 unFunB (IsoB _)    = isoErr "unFunB"
+BogusMatch(unFunB)
 
 exlB :: Buses (a :* b) -> Buses a
 exlB = fst . unPairB
@@ -801,7 +809,7 @@ class SourceToBuses a where toBuses :: Source -> Buses a
 instance SourceToBuses Bool   where toBuses = BoolB
 instance SourceToBuses Int    where toBuses = IntB
 instance SourceToBuses Float  where toBuses = FloatB
-instance SourceToBuses Double where toBuses = DoubleB
+instance SourceToBuses Doubli where toBuses = DoubleB
 
 sourceB :: SourceToBuses a => Source -> CircuitM (Maybe (Buses a))
 sourceB = justA . toBuses
diff --git a/src/Circat/Doubli.hs b/src/Circat/Doubli.hs
new file mode 100644
index 0000000..6855df0
--- /dev/null
+++ b/src/Circat/Doubli.hs
@@ -0,0 +1,24 @@
+{-# LANGUAGE GeneralizedNewtypeDeriving #-}
+{-# OPTIONS_GHC -Wall #-}
+
+-- {-# OPTIONS_GHC -fno-warn-unused-imports #-} -- TEMP
+-- {-# OPTIONS_GHC -fno-warn-unused-binds   #-} -- TEMP
+
+----------------------------------------------------------------------
+-- |
+-- Module      :  Circat.Doubli
+-- Copyright   :  (c) 2016 Conal Elliott
+-- License     :  BSD3
+--
+-- Maintainer  :  conal@conal.net
+-- Stability   :  experimental
+-- 
+-- newtype wrapper around Double to work around a problem finding instances
+-- defined in GHC.Float.
+----------------------------------------------------------------------
+
+module Circat.Doubli where
+
+newtype Doubli = Doubli Double
+ deriving (Enum,Eq,Floating,Fractional,Num,Ord,Read,Real,RealFloat,RealFrac,Show)
+
diff --git a/src/Circat/Prim.hs b/src/Circat/Prim.hs
index 93831de..6c86f37 100644
--- a/src/Circat/Prim.hs
+++ b/src/Circat/Prim.hs
@@ -59,6 +59,7 @@ import Circat.Circuit (GenBuses,(:>)
 import Circat.Misc
 import Circat.ShowUtils (Show'(..))
 import Circat.Show (showsApp1)
+import Circat.Doubli
 
 {--------------------------------------------------------------------
     Literals
@@ -70,7 +71,7 @@ data Lit :: * -> * where
   BoolL   :: Bool   -> Lit Bool
   IntL    :: Int    -> Lit Int
   FloatL  :: Float  -> Lit Float
-  DoubleL :: Double -> Lit Double
+  DoubleL :: Doubli -> Lit Doubli
 
 -- The Unit argument is just for uniformity
 
@@ -91,7 +92,7 @@ instance HasLit Unit   where toLit = UnitL
 instance HasLit Bool   where toLit = BoolL
 instance HasLit Int    where toLit = IntL
 instance HasLit Float  where toLit = FloatL
-instance HasLit Double where toLit = DoubleL
+instance HasLit Doubli where toLit = DoubleL
 
 -- TODO: Do I still need this stuff?