diff --git a/genvalidity-text.cabal b/genvalidity-text.cabal
--- a/genvalidity-text.cabal
+++ b/genvalidity-text.cabal
@@ -1,13 +1,13 @@
-cabal-version: >= 1.10
+cabal-version: 1.12
 
--- This file has been generated from package.yaml by hpack version 0.29.6.
+-- This file has been generated from package.yaml by hpack version 0.31.1.
 --
 -- see: https://github.com/sol/hpack
 --
--- hash: 0b74a2109a1d1a01ef347a56e9eb34ceafe87cdd703a165cc25c976325210d43
+-- hash: ea9d370a4d6e4e02b556f3e585c751532a53c5c09c0268d232ac5a3e7d861fea
 
 name:           genvalidity-text
-version:        0.5.1.0
+version:        0.6.0.0
 synopsis:       GenValidity support for Text
 description:    Please see README.md
 category:       Testing
@@ -16,7 +16,7 @@
 author:         Tom Sydney Kerckhove
 maintainer:     syd.kerckhove@gmail.com,
                 nick.van.den.broeck666@gmail.com
-copyright:      Copyright: (c) 2016-2018 Tom Sydney Kerckhove
+copyright:      Copyright: (c) 2016-2019 Tom Sydney Kerckhove
 license:        MIT
 license-file:   LICENSE
 build-type:     Simple
diff --git a/src/Data/GenValidity/Text.hs b/src/Data/GenValidity/Text.hs
--- a/src/Data/GenValidity/Text.hs
+++ b/src/Data/GenValidity/Text.hs
@@ -1,63 +1,39 @@
 {-# OPTIONS_GHC -fno-warn-orphans #-}
 {-# LANGUAGE CPP #-}
-
+#if MIN_VERSION_base(4,9,0)
+{-# LANGUAGE TypeOperators #-}
+{-# LANGUAGE DataKinds #-}
+{-# LANGUAGE UndecidableInstances #-}
+#endif
 module Data.GenValidity.Text where
 
 import Data.GenValidity
 import Data.Validity.Text ()
 
 import Test.QuickCheck
-
-import Control.Monad
 #if !MIN_VERSION_base(4,8,0)
 import Control.Applicative ((<*>), pure)
 import Data.Functor ((<$>))
 #endif
 import qualified Data.Text as ST
-import qualified Data.Text.Array as A
-import qualified Data.Text.Internal as ST
 import qualified Data.Text.Internal.Lazy as LT
-
-instance GenUnchecked ST.Text where
-    genUnchecked =
-        sized $ \n -> do
-            size <- upTo n
-            arr <-
-                do ins <- replicateM size arbitrary
-                   return $
-                       A.run $ do
-                           arr <- A.new size
-                           forM_ (zip [0 ..] ins) $ uncurry $ A.unsafeWrite arr
-                           return arr
-            off <- upTo $ max 0 (size - 1)
-            let len = size - off
-            pure $ ST.Text arr off len
-    shrinkUnchecked _ = []
-
+import qualified Data.Text.Lazy as LT
+#if MIN_VERSION_base(4,9,0)
+import GHC.TypeLits
+#endif
 instance GenValid ST.Text where
     genValid =
         sized $ \n -> do
-            size <- upTo n
-            chars <- resize size $ genListOf arbitrary
+            chars <- resize n $ genListOf arbitrary
             return $ ST.pack chars
     shrinkValid = fmap ST.pack . shrinkValid . ST.unpack
-
-instance GenInvalid ST.Text
-
-instance GenUnchecked LT.Text where
-    genUnchecked =
-        sized $ \n ->
-            case n of
-                0 -> pure LT.Empty
-                _ -> do
-                    (a, b) <- genSplit n
-                    st <- resize a genUnchecked
-                    lt <- resize b genUnchecked
-                    pure $ LT.Chunk st lt
-    shrinkUnchecked LT.Empty = []
-    shrinkUnchecked (LT.Chunk st lt) =
-        [LT.Chunk st' lt' | (st', lt') <- shrinkUnchecked (st, lt)]
-
+#if MIN_VERSION_base(4,9,0)
+-- If you see this error and want to learn more, have a look at docs/BYTESTRING.md
+instance GHC.TypeLits.TypeError ('GHC.TypeLits.Text "The GenUnchecked Data.Text.Text is disabled:" 'GHC.TypeLits.:$$: 'GHC.TypeLits.Text "Do not instantiate GenUnchecked, instantiate GenValid instead") =>
+         GenUnchecked ST.Text where
+    genUnchecked = error "unreachable"
+    shrinkUnchecked = error "unreachable"
+#endif
 instance GenValid LT.Text where
     genValid =
         sized $ \n ->
@@ -68,9 +44,14 @@
                     st <- ST.cons <$> genValid <*> resize a genValid
                     lt <- resize b genValid
                     pure $ LT.Chunk st lt
-
-instance GenInvalid LT.Text
-
+    shrinkValid = fmap LT.fromChunks . shrinkValid . LT.toChunks
+#if MIN_VERSION_base(4,9,0)
+-- If you see this error and want to learn more, have a look at docs/BYTESTRING.md
+instance GHC.TypeLits.TypeError ('GHC.TypeLits.Text "The GenUnchecked Data.Text.Lazy.Text is disabled:" 'GHC.TypeLits.:$$: 'GHC.TypeLits.Text "Do not instantiate GenUnchecked, instantiate GenValid instead") =>
+         GenUnchecked LT.Text where
+    genUnchecked = error "unreachable"
+    shrinkUnchecked = error "unreachable"
+#endif
 -- | 'textStartingWith c' generates a 'Text' value that starts with 'c'.
 textStartingWith :: Char -> Gen ST.Text
 textStartingWith c =
diff --git a/test/Data/GenValidity/TextSpec.hs b/test/Data/GenValidity/TextSpec.hs
--- a/test/Data/GenValidity/TextSpec.hs
+++ b/test/Data/GenValidity/TextSpec.hs
@@ -45,23 +45,20 @@
         [ "A chuck with this strict text:"
         , showTextDebug st
         , "and this rest of the lazy text:"
-        , showLazyTextDebug lt, ""
+        , showLazyTextDebug lt
+        , ""
         ]
 
 spec :: Spec
 spec = do
     describe "Strict Text" $ do
-        genValiditySpec @ST.Text
+        genValidSpec @ST.Text
         describe "genValid" $ do
             it "is always empty when resized to 0" $
                 forAll (resize 0 genValid) (`shouldSatisfy` ST.null)
             it "generates valid text" $
                 forAll (genValid) $ \t ->
                     unless (isValid t) $ expectationFailure $ showTextDebug t
-        describe "genUnchecked `suchThat` isValid" $
-            it "generates valid text" $
-            forAll ((genUnchecked :: Gen ST.Text) `suchThat` isValid) $ \t ->
-                unless (isValid t) $ expectationFailure $ showTextDebug t
         describe "textStartingWith" $ do
             it "is never empty" $
                 forAll arbitrary $ \c ->
@@ -93,7 +90,7 @@
                 forAll (textWithoutAnyOf cs) $ \text ->
                     ST.unpack text `shouldNotSatisfy` (\t -> any (`elem` t) cs)
     describe "Lazy Text" $ do
-        genValiditySpec @LT.Text
+        genValidSpec @LT.Text
         describe "genValid" $ do
             it "is always empty when resized to 0" $
                 forAll (resize 0 genValid) (`shouldSatisfy` LT.null)
@@ -101,7 +98,3 @@
                 forAll (genValid) $ \t ->
                     unless (isValid t) $
                     expectationFailure $ showLazyTextDebug t
-        describe "genUnchecked `suchThat` isValid" $
-            it "generates valid text" $
-            forAll ((genUnchecked :: Gen LT.Text) `suchThat` isValid) $ \t ->
-                unless (isValid t) $ expectationFailure $ showLazyTextDebug t