diff --git a/Data/Vector/Unboxed/Deriving.hs b/Data/Vector/Unboxed/Deriving.hs
--- a/Data/Vector/Unboxed/Deriving.hs
+++ b/Data/Vector/Unboxed/Deriving.hs
@@ -16,46 +16,22 @@
 Maintainer:  vector-th-unbox@liyang.hu
 Stability:   experimental
 Portability: non-portable
-
-Writing @Unbox@ instances for new data types is tedious and formulaic. More
-often than not, there is a straightforward mapping of the new type onto some
-existing one already imbued with an @Unbox@ instance. The
-<http://hackage.haskell.org/package/vector/docs/Data-Vector-Unboxed.html example>
-from the @vector@ package represents @Complex a@ as pairs @(a, a)@. Using
-'derivingUnbox', we can define the same instances much more succinctly:
-
->derivingUnbox "Complex"
->    [t| (Unbox a) ⇒ Complex a → (a, a) |]
->    [| \ (r :+ i) → (r, i) |]
->    [| \ (r, i) → r :+ i |]
-
-Requires the @MultiParamTypeClasses@, @TemplateHaskell@, @TypeFamilies@ and
-probably the @FlexibleInstances@ @LANGUAGE@ extensions. Note that GHC 7.4
-(but not earlier nor later) needs the 'G.Vector' and 'M.MVector' class
-method names to be in scope in order to define the appropriate instances:
-
->#if __GLASGOW_HASKELL__ == 704
->import qualified Data.Vector.Generic
->import qualified Data.Vector.Generic.Mutable
->#endif
-
-Consult the <https://github.com/liyang/vector-th-unbox/blob/master/tests/sanity.hs sanity test>
-for a working example.
 -}
 
-module Data.Vector.Unboxed.Deriving (derivingUnbox) where
+module Data.Vector.Unboxed.Deriving
+    ( -- $usage
+      derivingUnbox
+    ) where
 
 import Control.Arrow
 import Control.Applicative
 import Control.Monad
+import Data.Char (isAlphaNum)
 import qualified Data.Vector.Generic as G
 import qualified Data.Vector.Generic.Mutable as M
 import Data.Vector.Unboxed.Base (MVector (..), Vector (..), Unbox)
 import Language.Haskell.TH
 
-consUnbox :: String -> (Name, Name)
-consUnbox name = (mkName $ "MV_" ++ name, mkName $ "V_" ++ name)
-
 -- Create a @Pat@ bound to the given name and an @Exp@ for said binding.
 newPatExp :: String -> Q (Pat, Exp)
 newPatExp = fmap (VarP &&& VarE) . newName
@@ -66,7 +42,10 @@
 
 common :: String -> Q Common
 common name = do
-    let (mvName, vName) = consUnbox name
+    -- A bit looser than “Haskell 2010: §2.4 Identifiers and Operators”…
+    unless (all (\ c -> c == '\'' || c == '#' || isAlphaNum c) name) $ do
+        fail (show name ++ " is not a valid constructor suffix!")
+    let (mvName, vName) = (mkName $ "MV_" ++ name, mkName $ "V_" ++ name)
     i <- newPatExp "idx"
     n <- newPatExp "len"
     mv  <- first (ConP mvName . (:[])) <$> newPatExp "mvec"
@@ -108,7 +87,7 @@
 constraint. Thus:
 
 >derivingUnbox "Maybe"
->    [t| (Default a, Unbox a) ⇒ Maybe a → (Bool, a) |]
+>    [t| ∀ a. (Default a, Unbox a) ⇒ Maybe a → (Bool, a) |]
 >    [| maybe (False, def) (\ x → (True, x)) |]
 >    [| \ (b, x) → if b then Just x else Nothing |]
 -}
@@ -164,4 +143,34 @@
     return [ InstanceD cxts (ConT ''Unbox `AppT` typ) []
         , newtypeMVector, instanceMVector
         , newtypeVector, instanceVector ]
+
+#undef __GLASGOW_HASKELL__
+{-$usage
+
+Writing @Unbox@ instances for new data types is tedious and formulaic. More
+often than not, there is a straightforward mapping of the new type onto some
+existing one already imbued with an @Unbox@ instance. The
+<http://hackage.haskell.org/package/vector/docs/Data-Vector-Unboxed.html example>
+from the @vector@ package represents @Complex a@ as pairs @(a, a)@. Using
+'derivingUnbox', we can define the same instances much more succinctly:
+
+>derivingUnbox "Complex"
+>    [t| ∀ a. (Unbox a) ⇒ Complex a → (a, a) |]
+>    [| \ (r :+ i) → (r, i) |]
+>    [| \ (r, i) → r :+ i |]
+
+Requires the @MultiParamTypeClasses@, @TemplateHaskell@, @TypeFamilies@ and
+probably the @FlexibleInstances@ @LANGUAGE@ extensions. Note that GHC 7.4
+(but not earlier nor later) needs the 'G.Vector' and 'M.MVector' class
+method names to be in scope in order to define the appropriate instances:
+
+>#if __GLASGOW_HASKELL__ == 704
+>import qualified Data.Vector.Generic
+>import qualified Data.Vector.Generic.Mutable
+>#endif
+
+Consult the <https://github.com/liyang/vector-th-unbox/blob/master/tests/sanity.hs sanity test>
+for a working example.
+
+-}
 
diff --git a/tests/sanity.hs b/tests/sanity.hs
--- a/tests/sanity.hs
+++ b/tests/sanity.hs
@@ -1,5 +1,6 @@
 {-# LANGUAGE CPP #-}
 {-# LANGUAGE MultiParamTypeClasses #-}
+{-# LANGUAGE RankNTypes #-}
 {-# LANGUAGE TemplateHaskell #-}
 {-# LANGUAGE TypeFamilies #-}
 {-# LANGUAGE UnicodeSyntax #-}
@@ -17,7 +18,7 @@
 import Data.Vector.Unboxed.Deriving
 
 derivingUnbox "Maybe"
-    [t| (Default a, Unbox a) ⇒ Maybe a → (Bool, a) |]
+    [t| ∀ a. (Default a, Unbox a) ⇒ Maybe a → (Bool, a) |]
     [| maybe (False, def) (\ x → (True, x)) |]
     [| \ (b, x) → if b then Just x else Nothing |]
 
diff --git a/vector-th-unbox.cabal b/vector-th-unbox.cabal
--- a/vector-th-unbox.cabal
+++ b/vector-th-unbox.cabal
@@ -1,5 +1,5 @@
 name:           vector-th-unbox
-version:        0.2.1.0
+version:        0.2.1.1
 synopsis:       Deriver for Data.Vector.Unboxed using Template Haskell
 description:
     A Template Haskell deriver for unboxed vectors, given a pair of coercion
@@ -26,7 +26,7 @@
         Data.Vector.Unboxed.Deriving
 
     build-depends:
-        base >= 4.3 && < 5,
+        base >= 4.5 && < 5,
         template-haskell >= 2.5,
         vector >= 0.7