diff --git a/proto-lens.cabal b/proto-lens.cabal
--- a/proto-lens.cabal
+++ b/proto-lens.cabal
@@ -1,5 +1,5 @@
 name:                proto-lens
-version:             0.1.0.3
+version:             0.1.0.4
 synopsis:            A lens-based implementation of protocol buffers in Haskell.
 description:
   The proto-lens library provides to protocol buffers using modern
@@ -36,7 +36,7 @@
                 , base >= 4.8 && < 4.10
                 , bytestring == 0.10.*
                 , containers == 0.5.*
-                , data-default-class == 0.0.*
+                , data-default-class >= 0.0 && < 0.2
                 , lens-family == 1.2.*
                 , parsec == 3.1.*
                 , pretty == 1.1.*
diff --git a/src/Data/ProtoLens/TextFormat/Parser.hs b/src/Data/ProtoLens/TextFormat/Parser.hs
--- a/src/Data/ProtoLens/TextFormat/Parser.hs
+++ b/src/Data/ProtoLens/TextFormat/Parser.hs
@@ -19,6 +19,7 @@
 import Data.Functor.Identity (Identity)
 import Data.List (intercalate)
 import Data.Maybe (catMaybes)
+import Data.Monoid (mconcat)
 import Data.Text.Lazy (Text)
 import Data.Word (Word8)
 import Numeric (readOct, readHex)