diff --git a/Data/Ascii/Blaze.hs b/Data/Ascii/Blaze.hs
--- a/Data/Ascii/Blaze.hs
+++ b/Data/Ascii/Blaze.hs
@@ -4,6 +4,9 @@
 
 import Data.Ascii.ByteString
 
+-- base
+import Data.Semigroup (Semigroup)
+
 -- blaze-builder
 import qualified Blaze.ByteString.Builder as Blaze
 
diff --git a/Data/Ascii/ByteString.hs b/Data/Ascii/ByteString.hs
--- a/Data/Ascii/ByteString.hs
+++ b/Data/Ascii/ByteString.hs
@@ -7,6 +7,7 @@
 import Data.Typeable (Typeable)
 import Data.String (IsString (..))
 import qualified Data.Char as C
+import Data.Semigroup (Semigroup)
 
 -- bytestring
 import qualified Data.ByteString as S
diff --git a/ascii.cabal b/ascii.cabal
--- a/ascii.cabal
+++ b/ascii.cabal
@@ -1,5 +1,5 @@
 Name:                ascii
-Version:             0.0.5
+Version:             0.0.5.1
 Synopsis:            Type-safe, bytestring-based ASCII values.
 Description:         Type-safe, bytestring-based ASCII values.
 License:             BSD3
@@ -28,4 +28,5 @@
                      , blaze-builder    >= 0.2.1.4       && < 0.5
                      , case-insensitive >= 0.2           && < 1.3
                      , hashable         >= 1.0           && < 1.3
+                     , semigroups
   Ghc-options:         -Wall