diff --git a/Data/Double/Extra/Types.hs b/Data/Double/Extra/Types.hs
--- a/Data/Double/Extra/Types.hs
+++ b/Data/Double/Extra/Types.hs
@@ -1,3 +1,4 @@
+{-# LANGUAGE RoleAnnotations #-}
 module Data.Double.Extra.Types
  ( DoublePrecision(..)
  , DoubleExponential(..)
@@ -13,12 +14,15 @@
 
 newtype DoublePrecision (i :: Nat) = DoublePrecision Double
   deriving (Eq,Enum,Ord,Show,Read,Generic,NFData,Num,Fractional,Floating,Real,RealFrac)
+type role DoublePrecision phantom
 
 newtype DoubleExponential (i :: Nat) = DoubleExponential Double
   deriving (Eq,Enum,Ord,Show,Read,Generic,NFData,Num,Fractional,Floating,Real,RealFrac)
+type role DoubleExponential phantom
 
 newtype DoubleFixed (i :: Nat) = DoubleFixed Double
   deriving (Eq,Enum,Ord,Show,Read,Generic,NFData,Num,Fractional,Floating,Real,RealFrac)
+type role DoubleFixed phantom
 
 newtype DoubleShortest = DoubleShortest Double
   deriving (Eq,Enum,Ord,Show,Read,Generic,NFData,Num,Fractional,Floating,Real,RealFrac)
diff --git a/double-extra.cabal b/double-extra.cabal
--- a/double-extra.cabal
+++ b/double-extra.cabal
@@ -1,5 +1,5 @@
 name:                double-extra
-version:             0.1.0.3
+version:             0.1.0.4
 synopsis:            Missing presentations for Double numbers (fixed, scientific etc.)
 description:         Please see README.md
 homepage:            https://github.com/tolysz/double-extra#readme