diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -30,8 +30,10 @@
       - run: du -hd3 ~/.cabal ~/.ghc || true
 
       - run: haddock --version || sudo apt-get install ghc-haddock
-      - run: ghc   --version
-      - run: cabal --version
+      - run: ghc     --version
+      - run: cabal   --version
+      - run: haddock --version
+      - run: ghc-pkg list
 
       - name: Check out repository
         uses: actions/checkout@v2
@@ -86,8 +88,10 @@
       - run: make --version || apt-get update
       - run: make --version || apt-get install make
 
-      - run: ghc   --version
-      - run: cabal --version
+      - run: ghc     --version
+      - run: cabal   --version
+      - run: haddock --version
+      - run: ghc-pkg list
 
       - name: Check out repository
         uses: actions/checkout@v2
@@ -117,15 +121,8 @@
           key:          v1-${{ runner.os }}-stack-${{ hashFiles('stack.yaml') }}
           restore-keys: v1-${{ runner.os }}-stack-
 
-      - name: Check out repository
-        uses: actions/checkout@v2
-      - run: make test-via-stack
+      - run: stack --version
 
-  test-with-hugs:
-    runs-on: ubuntu-latest
-    needs: build-and-test
-    steps:
-      - run: sudo apt-get install hugs
       - name: Check out repository
         uses: actions/checkout@v2
-      - run: make hugs-test
+      - run: make test-via-stack
diff --git a/Makefile b/Makefile
--- a/Makefile
+++ b/Makefile
@@ -97,9 +97,6 @@
 test-via-stack:
 	stack test speculate:test:engine --ghc-options="$(GHCFLAGS) -O0" --system-ghc --no-install-ghc --no-terminal
 
-hugs-test:
-	echo 'Hugs is not supported at the moment'
-
 legacy-test:
 	make clean  &&  make -j8 GHC=ghc-8.2   &&  make quick-test -j8 GHC=ghc-8.2
 	make clean  &&  make -j8 GHC=ghc-8.0   &&  make quick-test -j8 GHC=ghc-8.0
diff --git a/eg/binarytree.hs b/eg/binarytree.hs
--- a/eg/binarytree.hs
+++ b/eg/binarytree.hs
@@ -95,8 +95,6 @@
 instance Name (BT a) where name _ = "t"
 instance Name Word2 where name _ = "x"
 
-deriving instance Typeable Word2 -- for GHC <= 7.8
-
 type Item = Word2
 
 main :: IO ()
diff --git a/eg/binarytree0.hs b/eg/binarytree0.hs
--- a/eg/binarytree0.hs
+++ b/eg/binarytree0.hs
@@ -91,8 +91,6 @@
 instance Name (BT a) where name _ = "t"
 instance Name Word2 where name _ = "x"
 
-deriving instance Typeable Word2 -- for GHC <= 7.8
-
 type Item = Word2
 
 main :: IO ()
diff --git a/eg/digraphs.hs b/eg/digraphs.hs
--- a/eg/digraphs.hs
+++ b/eg/digraphs.hs
@@ -10,7 +10,6 @@
 #else
 deriving instance Typeable Digraph
 #endif
-deriving instance Typeable Nat
 #endif
 
 instance Ord a => Ord (Digraph a) where
diff --git a/speculate.cabal b/speculate.cabal
--- a/speculate.cabal
+++ b/speculate.cabal
@@ -1,5 +1,5 @@
 name:                speculate
-version:             0.4.8
+version:             0.4.10
 synopsis:            discovery of properties about Haskell functions
 description:
   Speculate automatically discovers laws about Haskell functions.
@@ -69,7 +69,8 @@
                   , test/update-diff
                   , test/sdist
 
-tested-with: GHC==8.10
+tested-with: GHC==9.0
+           , GHC==8.10
            , GHC==8.8
            , GHC==8.6
            , GHC==8.4
@@ -85,7 +86,7 @@
 source-repository this
   type:            git
   location:        https://github.com/rudymatela/speculate
-  tag:             v0.4.8
+  tag:             v0.4.10
 
 
 library
diff --git a/stack.yaml b/stack.yaml
--- a/stack.yaml
+++ b/stack.yaml
@@ -4,5 +4,5 @@
 - .
 
 extra-deps:
-- leancheck-0.9.6
-- express-0.1.10
+- leancheck-0.9.10
+- express-0.1.14