diff --git a/semver.cabal b/semver.cabal
--- a/semver.cabal
+++ b/semver.cabal
@@ -1,5 +1,5 @@
 name:                  semver
-version:               0.1.1
+version:               0.1.2
 synopsis:              Representation, manipulation, and de/serialisation of Semantic Versions.
 homepage:              https://github.com/brendanhay/semver
 license:               OtherLicense
diff --git a/src/Data/SemVer.hs b/src/Data/SemVer.hs
--- a/src/Data/SemVer.hs
+++ b/src/Data/SemVer.hs
@@ -79,7 +79,6 @@
 import           Data.Function              (on)
 import           Data.List                  (intersperse)
 import           Data.Monoid
-import           Data.String
 import           Data.Text                  (Text)
 import qualified Data.Text                  as Text
 import qualified Data.Text.Lazy             as LText
@@ -108,11 +107,6 @@
         (INum  _, _)       -> LT
         (IText _, _)       -> GT
 
-instance IsString Identifier where
-    fromString s
-        | all isDigit s = INum  (read s)
-        | otherwise     = IText (fromString s)
-
 instance NFData Identifier where
     rnf (INum  n) = rnf n
     rnf (IText t) = rnf t
@@ -196,7 +190,7 @@
 -- let Right v = fromText "1.2.3+40"
 -- let alpha   = Delimiters \'m\' \'p\' \'r\' \'d\' \'i\'
 --
--- Data.Text.Lazy.Builder.toLazyText ("app01-" <> toDelimitedBuilder alpha v <> ".dmz.internal")
+-- Data.Text.Lazy.Builder.toLazyText (\"app01-\" <> toDelimitedBuilder alpha v <> \".dmz.internal\")
 -- @
 --
 -- Would result in the following 'LText.Text':