From 798a8f37e17474355b4bf7419e40cc0b994ad6c0 Mon Sep 17 00:00:00 2001
From: Alexey Kuleshevich <alexey@kuleshevi.ch>
Date: Sun, 25 Jul 2021 22:20:16 +0300
Subject: [PATCH 1/2] Add StatefulGen instance for Gen

---
 src/Test/QuickCheck.hs     |  1 +
 src/Test/QuickCheck/Gen.hs | 14 +++++++++++++-
 2 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/src/Test/QuickCheck.hs b/src/Test/QuickCheck.hs
index 405ced04..2376f53d 100644
--- a/src/Test/QuickCheck.hs
+++ b/src/Test/QuickCheck.hs
@@ -93,6 +93,7 @@ module Test.QuickCheck
 
     -- * The 'Gen' monad: combinators for building random generators
   , Gen
+  , QC(..)
     -- ** Generator combinators
   , choose
   , chooseInt
diff --git a/src/Test/QuickCheck/Gen.hs b/src/Test/QuickCheck/Gen.hs
index ee1507a7..537c5a10 100644
--- a/src/Test/QuickCheck/Gen.hs
+++ b/src/Test/QuickCheck/Gen.hs
@@ -1,4 +1,5 @@
 {-# LANGUAGE CPP #-}
+{-# LANGUAGE MultiParamTypeClasses #-}
 #ifndef NO_ST_MONAD
 {-# LANGUAGE Rank2Types #-}
 #endif
@@ -42,7 +43,9 @@ import Data.Word
 import Data.Int
 import Data.Bits
 import Control.Applicative
-
+#ifndef OLD_RANDOM
+import System.Random.Stateful
+#endif
 --------------------------------------------------------------------------
 -- ** Generator type
 
@@ -92,6 +95,15 @@ instance MonadFix Gen where
       let a = unGen (f a) r n
       in a
 
+#ifndef OLD_RANDOM
+data QC = QC
+
+instance StatefulGen QC Gen where
+  uniformWord32 QC = MkGen (\r _n -> runStateGen_ r uniformWord32)
+  uniformWord64 QC = MkGen (\r _n -> runStateGen_ r uniformWord64)
+  uniformShortByteString k QC =
+    MkGen (\r _n -> runStateGen_ r (uniformShortByteString k))
+#endif
 --------------------------------------------------------------------------
 -- ** Primitive generator combinators
 

From 79115356c56753894516e6943394ee3806b7974c Mon Sep 17 00:00:00 2001
From: Alexey Kuleshevich <alexey@kuleshevi.ch>
Date: Sun, 25 Jul 2021 22:42:07 +0300
Subject: [PATCH 2/2] Forgot some CPP

---
 src/Test/QuickCheck.hs | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/src/Test/QuickCheck.hs b/src/Test/QuickCheck.hs
index 2376f53d..1c91a681 100644
--- a/src/Test/QuickCheck.hs
+++ b/src/Test/QuickCheck.hs
@@ -93,7 +93,9 @@ module Test.QuickCheck
 
     -- * The 'Gen' monad: combinators for building random generators
   , Gen
+#ifndef OLD_RANDOM
   , QC(..)
+#endif
     -- ** Generator combinators
   , choose
   , chooseInt