diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
new file mode 100644
--- /dev/null
+++ b/.github/workflows/build.yml
@@ -0,0 +1,130 @@
+# Builds and tests this Haskell project on "GitHub Actions"
+#
+# 2021  Rudy Matela
+#
+# some docs: https://github.com/haskell/actions/tree/main/setup
+name: build
+on: [push]
+jobs:
+  build-and-test:
+    runs-on: ubuntu-latest
+    steps:
+
+      - name: Cache ~/.cabal/packages
+        uses: actions/cache@v2
+        with:
+          path: ~/.cabal/packages
+          key:          v1-${{ runner.os }}-cabal-packages-${{ hashFiles('hello.cabal') }}
+          restore-keys: v1-${{ runner.os }}-cabal-packages-
+
+      - name: Cache ~/.cabal and ~/.ghc
+        uses: actions/cache@v2
+        with:
+          path: |
+            ~/.cabal
+            !~/.cabal/packages
+            ~/.ghc
+          key:          v1-${{ runner.os }}-cabal-ghc-latest-${{ hashFiles('hello.cabal') }}
+          restore-keys: v1-${{ runner.os }}-cabal-ghc-latest-
+
+      - run: du -hd3 ~/.cabal ~/.ghc || true
+
+      - run: haddock --version || sudo apt-get install ghc-haddock
+      - run: ghc     --version
+      - run: cabal   --version
+      - run: haddock --version
+      - run: ghc-pkg list
+
+      - name: Check out repository
+        uses: actions/checkout@v2
+
+      - run: cabal update
+      - run: make install-dependencies
+
+      - run: make
+      - run: make test
+      - run: make haddock
+      - run: make test-sdist
+      - run: make test-via-cabal
+
+
+  test-with-ghc:
+    strategy:
+      matrix:
+        ghc:
+          - '9.4'
+          - '9.2'
+          - '9.0'
+          - '8.10'
+          - '8.8'
+          - '8.6'
+          - '8.4'
+          - '8.2'
+          - '8.0'
+          - '7.10'
+          - '7.8'
+    runs-on: ubuntu-latest
+    needs: build-and-test
+    container: haskell:${{ matrix.ghc }}
+    steps:
+      - name: Cache ~/.cabal/packages
+        uses: actions/cache@v2
+        with:
+          path: ~/.cabal/packages
+          key:          v1-${{ runner.os }}-cabal-packages-${{ hashFiles('hello.cabal') }}
+          restore-keys: v1-${{ runner.os }}-cabal-packages-
+
+      - name: Cache ~/.cabal and ~/.ghc
+        uses: actions/cache@v2
+        with:
+          path: |
+            ~/.cabal
+            !~/.cabal/packages
+            ~/.ghc
+          key:          v1-${{ runner.os }}-cabal-ghc-${{ matrix.ghc }}-${{ hashFiles('hello.cabal') }}
+          restore-keys: v1-${{ runner.os }}-cabal-ghc-${{ matrix.ghc }}-
+
+      - run: du -hd3 ~/.cabal ~/.ghc || true
+
+      - run: make --version || rm /etc/apt/sources.list.d/*.list # faster update
+      - run: make --version || apt-get update
+      - run: make --version || apt-get install make
+
+      - run: ghc     --version
+      - run: cabal   --version
+      - run: haddock --version
+      - run: ghc-pkg list
+
+      - name: Check out repository
+        uses: actions/checkout@v2
+
+      - run: cabal update
+      - run: make install-dependencies
+
+      - run: make
+      - run: make test
+      - run: make haddock
+      - run: make test-sdist
+      - run: make test-via-cabal
+
+  test-with-stack:
+    runs-on: ubuntu-latest
+    needs: build-and-test
+    steps:
+      - name: Setup Haskell's GHC and Cabal as required by current Stackage LTS
+        uses: haskell/actions/setup@v1
+        with: # lts-19.19
+          ghc-version: '9.0.2'
+          cabal-version: '3.4'
+
+      - uses: actions/cache@v2
+        with:
+          path: ~/.stack
+          key:          v1-${{ runner.os }}-stack-${{ hashFiles('stack.yaml') }}
+          restore-keys: v1-${{ runner.os }}-stack-
+
+      - run: stack --version
+
+      - name: Check out repository
+        uses: actions/checkout@v2
+      - run: make test-via-stack
diff --git a/.travis.yml b/.travis.yml
deleted file mode 100644
--- a/.travis.yml
+++ /dev/null
@@ -1,90 +0,0 @@
-# .travis.yml file for leancheck-instances
-#
-# Copyright:   (c) 2017-2020 Rudy Matela
-# License:     3-Clause BSD  (see the file LICENSE)
-# Maintainer:  Rudy Matela <rudy@matela.com.br>
-
-language: c  # not really
-
-notifications:
-  email:
-    on_failure: change
-
-sudo: false
-
-cache:
-  directories:
-  - $HOME/.ghc
-  - $HOME/.cabal
-  - $HOME/.stack
-
-before_install:
-- export PATH=/opt/ghc/$GHCVER/bin:/opt/cabal/$CABALVER/bin:$PATH
-- ghc --version
-- cabal --version
-- haddock --version
-- du -hd3 ~/.cabal ~/.ghc || true
-- du -hd4 ~/.stack || true
-- rm -f ~/.cabal/config && cabal update
-# Download and unpack the stack executable
-# "Once Travis whitelists the stack.dev files," simply include stack in the
-# addons section. -- https://docs.haskellstack.org/en/stable/travis_ci/
-- mkdir -p ~/.local/bin
-- export PATH=$HOME/.local/bin:$PATH
-- travis_retry curl -L https://www.stackage.org/stack/linux-x86_64 | tar xz --wildcards --strip-components=1 -C ~/.local/bin '*/stack'
-- stack config set system-ghc --global true
-- stack --version
-- cabal install leancheck bytestring nats text || cabal install leancheck bytestring nats text --lib
-
-script:
-- make && make test
-- make haddock
-- make test-sdist
-- cabal test --ghc-option=-O0
-- stack --resolver $STACKVER --no-terminal --skip-ghc-check test --ghc-options=-O0
-
-matrix:
-  allow_failures:
-  - ghc: 'head'
-  include:
-  - ghc: 'head'
-    env:                   GHCVER=head         CABALVER=head   STACKVER=nightly-2020-03-28
-    addons: {apt: {packages: [ghc-head,   cabal-install-head], sources: hvr-ghc}}
-  - ghc: '8.10'
-    env:                   GHCVER=8.10.1       CABALVER=3.2    STACKVER=nightly-2020-03-28
-    addons: {apt: {packages: [ghc-8.10.1, cabal-install-3.2],  sources: hvr-ghc}}
-  - ghc: '8.8'
-    env:                   GHCVER=8.8.3        CABALVER=3.0    STACKVER=lts-15.5
-    addons: {apt: {packages: [ghc-8.8.3,  cabal-install-3.0],  sources: hvr-ghc}}
-  - ghc: '8.6'
-    env:                   GHCVER=8.6.5        CABALVER=2.4    STACKVER=lts-14.27
-    addons: {apt: {packages: [ghc-8.6.5,  cabal-install-2.4],  sources: hvr-ghc}}
-  - ghc: '8.4'
-    env:                   GHCVER=8.4.4        CABALVER=2.2    STACKVER=lts-12.26
-    addons: {apt: {packages: [ghc-8.4.4,  cabal-install-2.2],  sources: hvr-ghc}}
-  - ghc: '8.2'
-    env:                   GHCVER=8.2.2        CABALVER=2.0    STACKVER=lts-11.22
-    addons: {apt: {packages: [ghc-8.2.2,  cabal-install-2.0],  sources: hvr-ghc}}
-  - ghc: '8.0'
-    env:                   GHCVER=8.0.2        CABALVER=1.24   STACKVER=lts-9.21
-    addons: {apt: {packages: [ghc-8.0.2,  cabal-install-1.24], sources: hvr-ghc}}
-  - ghc: '7.10'
-    env:                   GHCVER=7.10.3       CABALVER=1.22   STACKVER=lts-6.35
-    addons: {apt: {packages: [ghc-7.10.3, cabal-install-1.22], sources: hvr-ghc}}
-  # we only support stack with GHC >= 7.10
-  - ghc: '7.8'
-    env:                   GHCVER=7.8.4        CABALVER=1.18
-    addons: {apt: {packages: [ghc-7.8.4,  cabal-install-1.18], sources: hvr-ghc}}
-    before_install:
-    - export PATH=/opt/ghc/$GHCVER/bin:/opt/cabal/$CABALVER/bin:$PATH
-    - ghc --version
-    - cabal --version
-    - haddock --version
-    - rm -f ~/.cabal/config && cabal update
-    - cabal install Cabal==1.18.*
-    - cabal install leancheck bytestring nats text
-    script:
-    - make && make test
-    - make haddock HADDOCKFLAGS=
-    - make test-sdist
-    - cabal test
diff --git a/Makefile b/Makefile
--- a/Makefile
+++ b/Makefile
@@ -1,6 +1,6 @@
 # Makefile for leancheck-instances
 #
-# Copyright:   (c) 2015-2018 Rudy Matela
+# Copyright:   (c) 2015-2022 Rudy Matela
 # License:     3-Clause BSD  (see the file LICENSE)
 # Maintainer:  Rudy Matela <rudy@matela.com.br>
 TESTS = test/main      \
@@ -11,9 +11,10 @@
 	bench/tiers
 GHCIMPORTDIRS = src:test
 # -dynamic is needed only for src/Test/LeanCheck/Derive.hs and test/derive.hs
-GHCFLAGS = -O2 $(shell grep -q "Arch Linux" /etc/lsb-release && echo -dynamic)
-HADDOCKFLAGS = --no-print-missing-docs \
+GHCFLAGS = -v0 -O2 $(shell grep -q "Arch Linux" /etc/lsb-release && echo -dynamic)
+HADDOCKFLAGS = \
   $(shell grep -q "Arch Linux" /etc/lsb-release && echo --optghc=-dynamic)
+INSTALL_DEPS = leancheck bytestring nats text --avoid-reinstalls
 
 all: mk/toplibs
 
@@ -50,10 +51,12 @@
 	./test/sdist
 
 test-via-cabal:
-	cabal test
+	cabal configure --enable-tests --enable-benchmarks --ghc-options="$(GHCFLAGS) -O0"
+	cabal build
+	cabal test main
 
 test-via-stack:
-	stack test
+	stack test leancheck-instances:test:main --ghc-options="$(GHCFLAGS) -O0" --system-ghc --no-install-ghc --no-terminal
 
 legacy-test: # needs ghc-8.2 .. ghc-7.8 installed as such
 	make clean  &&  make test GHC=ghc-8.2  GHCFLAGS="-Werror -dynamic"
diff --git a/README.md b/README.md
--- a/README.md
+++ b/README.md
@@ -173,8 +173,8 @@
 [quickcheck-instances]:                  https://hackage.haskell.org/package/quickcheck-instances
 [leancheck-instances]:                   https://hackage.haskell.org/package/leancheck-instances
 
-[build-status]: https://travis-ci.org/rudymatela/leancheck-instances.svg?branch=master
-[build-log]:    https://travis-ci.org/rudymatela/leancheck-instances
+[build-log]:    https://github.com/rudymatela/leancheck-instances/actions/workflows/build.yml
+[build-status]: https://github.com/rudymatela/leancheck-instances/actions/workflows/build.yml/badge.svg
 [hackage-version]: https://img.shields.io/hackage/v/leancheck-instances.svg
 [leancheck-instances-on-hackage]:          https://hackage.haskell.org/package/leancheck-instances
 [stackage-lts-badge]:                      https://stackage.org/package/leancheck-instances/badge/lts
diff --git a/bench/tiers.hs b/bench/tiers.hs
--- a/bench/tiers.hs
+++ b/bench/tiers.hs
@@ -1,6 +1,6 @@
 -- tiers.hs -- prints tiers of values up to a certain point
 --
--- Copyright (c) 2015-2018 Rudy Matela.
+-- Copyright (c) 2015-2022 Rudy Matela.
 -- Distributed under the 3-Clause BSD licence (see the file LICENSE).
 import Test.LeanCheck
 import Test.LeanCheck.Instances
diff --git a/changelog.md b/changelog.md
--- a/changelog.md
+++ b/changelog.md
@@ -1,6 +1,13 @@
 Changelog for leancheck-instances
 =================================
 
+v0.0.5
+------
+
+* add `Listable Void` instance;
+* CI using GitHub actions instead of Travis;
+
+
 v0.0.4
 ------
 
diff --git a/eg/test-text.hs b/eg/test-text.hs
--- a/eg/test-text.hs
+++ b/eg/test-text.hs
@@ -1,6 +1,6 @@
 -- test-list.hs -- example program, testing Data.List using LeanCheck
 --
--- Copyright (c) 2017-2018 Rudy Matela.
+-- Copyright (c) 2017-2022 Rudy Matela.
 -- Distributed under the 3-Clause BSD licence (see the file LICENSE).
 import Test.LeanCheck
 import Test.LeanCheck.Instances
diff --git a/leancheck-instances.cabal b/leancheck-instances.cabal
--- a/leancheck-instances.cabal
+++ b/leancheck-instances.cabal
@@ -1,6 +1,6 @@
 -- Cabal file for leancheck-instances
 name:                leancheck-instances
-version:             0.0.4
+version:             0.0.5
 synopsis:            Common LeanCheck instances
 description:
   Listable instances for types provided by the Haskell Platform.
@@ -21,7 +21,7 @@
                , TODO.md
                , changelog.md
 extra-source-files: .gitignore
-                  , .travis.yml
+                  , .github/workflows/build.yml
                   , Makefile
                   , bench/tiers.hs
                   , eg/test-text.hs
@@ -36,7 +36,10 @@
                   , test/diff/*.out
                   , test/diff/eg/*.out
                   , test/sdist
-tested-with: GHC==8.10
+tested-with: GHC==9.4
+           , GHC==9.2
+           , GHC==9.0
+           , GHC==8.10
            , GHC==8.8
            , GHC==8.6
            , GHC==8.4
@@ -53,7 +56,7 @@
 source-repository this
   type:            git
   location:        https://github.com/rudymatela/leancheck-instances
-  tag:             v0.0.4
+  tag:             v0.0.5
 
 library
   exposed-modules: Test.LeanCheck.Instances
@@ -63,6 +66,7 @@
                  , Test.LeanCheck.Instances.Natural
                  , Test.LeanCheck.Instances.ByteString
                  , Test.LeanCheck.Instances.Containers
+                 , Test.LeanCheck.Instances.Void
                  , Test.LeanCheck.WithInstances
   hs-source-dirs: src
   build-depends: base >= 4 && < 5
diff --git a/mk/depend.mk b/mk/depend.mk
--- a/mk/depend.mk
+++ b/mk/depend.mk
@@ -2,6 +2,7 @@
   bench/tiers.hs \
   mk/toplibs
 bench/tiers.o: \
+  src/Test/LeanCheck/Instances/Void.hs \
   src/Test/LeanCheck/Instances/Time.hs \
   src/Test/LeanCheck/Instances/Text.hs \
   src/Test/LeanCheck/Instances.hs \
@@ -14,6 +15,7 @@
   eg/test-text.hs \
   mk/toplibs
 eg/test-text.o: \
+  src/Test/LeanCheck/Instances/Void.hs \
   src/Test/LeanCheck/Instances/Time.hs \
   src/Test/LeanCheck/Instances/Text.hs \
   src/Test/LeanCheck/Instances.hs \
@@ -23,6 +25,7 @@
   src/Test/LeanCheck/Instances/Array.hs \
   eg/test-text.hs
 mk/All.o: \
+  src/Test/LeanCheck/Instances/Void.hs \
   src/Test/LeanCheck/Instances/Time.hs \
   src/Test/LeanCheck/Instances/Text.hs \
   src/Test/LeanCheck/Instances.hs \
@@ -32,6 +35,7 @@
   src/Test/LeanCheck/Instances/Array.hs \
   mk/All.hs
 mk/Toplibs.o: \
+  src/Test/LeanCheck/Instances/Void.hs \
   src/Test/LeanCheck/Instances/Time.hs \
   src/Test/LeanCheck/Instances/Text.hs \
   src/Test/LeanCheck/Instances.hs \
@@ -51,6 +55,7 @@
 src/Test/LeanCheck/Instances/Natural.o: \
   src/Test/LeanCheck/Instances/Natural.hs
 src/Test/LeanCheck/Instances.o: \
+  src/Test/LeanCheck/Instances/Void.hs \
   src/Test/LeanCheck/Instances/Time.hs \
   src/Test/LeanCheck/Instances/Text.hs \
   src/Test/LeanCheck/Instances.hs \
@@ -62,8 +67,11 @@
   src/Test/LeanCheck/Instances/Text.hs
 src/Test/LeanCheck/Instances/Time.o: \
   src/Test/LeanCheck/Instances/Time.hs
+src/Test/LeanCheck/Instances/Void.o: \
+  src/Test/LeanCheck/Instances/Void.hs
 src/Test/LeanCheck/WithInstances.o: \
   src/Test/LeanCheck/WithInstances.hs \
+  src/Test/LeanCheck/Instances/Void.hs \
   src/Test/LeanCheck/Instances/Time.hs \
   src/Test/LeanCheck/Instances/Text.hs \
   src/Test/LeanCheck/Instances.hs \
@@ -73,6 +81,7 @@
   src/Test/LeanCheck/Instances/Array.hs
 test/main.o: \
   test/main.hs \
+  src/Test/LeanCheck/Instances/Void.hs \
   src/Test/LeanCheck/Instances/Time.hs \
   src/Test/LeanCheck/Instances/Text.hs \
   src/Test/LeanCheck/Instances.hs \
@@ -85,6 +94,7 @@
   mk/toplibs
 test/text.o: \
   test/text.hs \
+  src/Test/LeanCheck/Instances/Void.hs \
   src/Test/LeanCheck/Instances/Time.hs \
   src/Test/LeanCheck/Instances/Text.hs \
   src/Test/LeanCheck/Instances.hs \
diff --git a/mk/ghcdeps b/mk/ghcdeps
--- a/mk/ghcdeps
+++ b/mk/ghcdeps
@@ -2,7 +2,7 @@
 #
 # ghcdeps: generate Haskell make dependencies for compiling with GHC.
 #
-# Copyright (c) 2015-2020 Rudy Matela.
+# Copyright (c) 2015-2021 Rudy Matela.
 # Distributed under the 3-Clause BSD licence.
 #
 # From a list of files provided on standard input,
@@ -46,4 +46,5 @@
 	rm -f tmp.mk
 done |
 sort |
+grep -v "^Loaded package environment from " |
 sed -e 's,  *, \\\n  ,g'
diff --git a/mk/haddock-i b/mk/haddock-i
--- a/mk/haddock-i
+++ b/mk/haddock-i
@@ -2,7 +2,7 @@
 #
 # haddock-i: list haddock's -i parameters.
 #
-# Copyright (c) 2015-2020 Rudy Matela.
+# Copyright (c) 2015-2021 Rudy Matela.
 # Distributed under the 3-Clause BSD licence.
 #
 # $ haddock-i <package1> <package2> ... <packageN>
diff --git a/mk/haskell.mk b/mk/haskell.mk
--- a/mk/haskell.mk
+++ b/mk/haskell.mk
@@ -1,6 +1,6 @@
 # Implicit rules for compiling Haskell code.
 #
-# Copyright (c) 2015-2020 Rudy Matela.
+# Copyright (c) 2015-2021 Rudy Matela.
 # Distributed under the 3-Clause BSD licence.
 #
 # You can optionally configure the "Configuration variables" below in your main
@@ -21,6 +21,7 @@
 GHC ?= ghc
 GHCCMD = $(GHC) -i$(GHCIMPORTDIRS) $(GHCFLAGS)
 HADDOCK ?= haddock
+CABAL_INSTALL = $(shell cabal --version | grep -q "version [0-2]\." && echo 'cabal install' || echo 'cabal v1-install')
 
 # Hugs Parameters
 HUGSIMPORTDIRS ?= "/usr/lib/hugs/packages/*"
@@ -46,19 +47,13 @@
 
 LIB_DEPS ?= base
 ALL_DEPS ?= $(LIB_DEPS)
+INSTALL_DEPS ?=
 
 PKGNAME = $(shell cat *.cabal | grep "^name:"    | sed -e "s/name: *//")
-HADDOCK_VERSION = $(shell $(HADDOCK) --version | grep version | sed -e 's/.*version //;s/,.*//')
-HADDOCK_MAJOR = $(shell echo $(HADDOCK_VERSION) | sed -e 's/\..*//')
-HADDOCK_MINOR = $(shell echo $(HADDOCK_VERSION) | sed -e 's/[0-9]*\.\([0-9]*\).[0-9]*/\1/')
-HADDOCK_PKG_NAME = $(shell [ $(HADDOCK_MAJOR) -gt 2 ] \
-                        || [ $(HADDOCK_MAJOR) -eq 2 -a $(HADDOCK_MINOR) -ge 20 ] \
-                        && echo "--package-name=$(PKGNAME)")
-HADDOCK_HLNK_SRC = $(shell [ $(HADDOCK_MAJOR) -gt 2 ] \
-                        || [ $(HADDOCK_MAJOR) -eq 2 -a $(HADDOCK_MINOR) -ge 17 ] \
-                        && echo "--hyperlinked-source")
 
+HADDOCK_HAS = haddock --help | grep -q --
 
+
 # Implicit rules
 %.hi %.o: %.hs
 	$(GHCCMD) $< && touch $@
@@ -80,7 +75,8 @@
 
 
 # Cleaning rule (add as a clean dependency)
-.PHONY: clean-hi-o
+clean-hs: clean-hi-o clean-haddock clean-cabal clean-stack
+
 clean-hi-o:
 	find $(ALL_HSS) | sed -e 's/hs$$/o/'      | xargs rm -f
 	find $(ALL_HSS) | sed -e 's/hs$$/hi/'     | xargs rm -f
@@ -93,6 +89,9 @@
 depend:
 	find $(ALL_HSS) | ./mk/ghcdeps -i$(GHCIMPORTDIRS) $(GHCFLAGS) > $(DEPMK)
 
+install-dependencies:
+	$(CABAL_INSTALL) $(INSTALL_DEPS)
+
 # haddock rules
 haddock: doc/index.html
 
@@ -109,10 +108,16 @@
 	./mk/haddock-i $(LIB_DEPS) | xargs \
 	$(HADDOCK) --html -odoc $(LIB_HSS) \
 	  --title=$(PKGNAME) \
-	  $(HADDOCK_PKG_NAME) \
-	  $(HADDOCK_HLNK_SRC) \
+	  $(shell $(HADDOCK_HAS) --package-name          && echo "--package-name=$(PKGNAME)" ) \
+	  $(shell $(HADDOCK_HAS) --hyperlinked-source    && echo "--hyperlinked-source"      ) \
+	  $(shell $(HADDOCK_HAS) --no-print-missing-docs && echo --no-print-missing-docs     ) \
 	  $(HADDOCKFLAGS)
 
+clean-cabal:
+	rm -rf dist/ dist-newstyle/ cabal.project.local cabal.project.local~
+
+clean-stack:
+	rm -rf .stack-work/ stack.yaml.lock
 
 # lists all Haskell source files
 list-all-hss:
diff --git a/mk/install-on b/mk/install-on
--- a/mk/install-on
+++ b/mk/install-on
@@ -2,9 +2,12 @@
 #
 # mk/install-on: install or updates the mk folder on a Haskell project
 #
+# Copyright (c) 2019-2021 Rudy Matela.
+# Distributed under the 3-Clause BSD licence.
+#
 # usage: ./mk/install-on path/to/project
 #
-# This assumes a few things:
+# This script assumes that:
 #
 # * tests are stored in a "test/" folder
 # * sources are stored in a "src/" folder
diff --git a/src/Test/LeanCheck/Instances.hs b/src/Test/LeanCheck/Instances.hs
--- a/src/Test/LeanCheck/Instances.hs
+++ b/src/Test/LeanCheck/Instances.hs
@@ -1,6 +1,6 @@
 -- |
 -- Module      : Test.LeanCheck.Instances
--- Copyright   : (c) 2018 Rudy Matela
+-- Copyright   : (c) 2018-2022 Rudy Matela
 -- License     : 3-Clause BSD  (see the file LICENSE)
 -- Maintainer  : Rudy Matela <rudy@matela.com.br>
 --
@@ -39,3 +39,4 @@
 import Test.LeanCheck.Instances.ByteString ()
 import Test.LeanCheck.Instances.Containers ()
 import Test.LeanCheck.Instances.Time ()
+import Test.LeanCheck.Instances.Void ()
diff --git a/src/Test/LeanCheck/Instances/Array.hs b/src/Test/LeanCheck/Instances/Array.hs
--- a/src/Test/LeanCheck/Instances/Array.hs
+++ b/src/Test/LeanCheck/Instances/Array.hs
@@ -1,6 +1,6 @@
 -- |
 -- Module      : Test.LeanCheck.Instances.Array
--- Copyright   : (c) 2019 Rudy Matela
+-- Copyright   : (c) 2019-2022 Rudy Matela
 -- License     : 3-Clause BSD  (see the file LICENSE)
 -- Maintainer  : Rudy Matela <rudy@matela.com.br>
 --
diff --git a/src/Test/LeanCheck/Instances/ByteString.hs b/src/Test/LeanCheck/Instances/ByteString.hs
--- a/src/Test/LeanCheck/Instances/ByteString.hs
+++ b/src/Test/LeanCheck/Instances/ByteString.hs
@@ -1,6 +1,6 @@
 -- |
 -- Module      : Test.LeanCheck.Instances.ByteString
--- Copyright   : (c) 2018 Rudy Matela
+-- Copyright   : (c) 2018-2022 Rudy Matela
 -- License     : 3-Clause BSD  (see the file LICENSE)
 -- Maintainer  : Rudy Matela <rudy@matela.com.br>
 --
diff --git a/src/Test/LeanCheck/Instances/Containers.hs b/src/Test/LeanCheck/Instances/Containers.hs
--- a/src/Test/LeanCheck/Instances/Containers.hs
+++ b/src/Test/LeanCheck/Instances/Containers.hs
@@ -1,6 +1,6 @@
 -- |
 -- Module      : Test.LeanCheck.Instances.Containers
--- Copyright   : (c) 2018 Rudy Matela
+-- Copyright   : (c) 2018-2022 Rudy Matela
 -- License     : 3-Clause BSD  (see the file LICENSE)
 -- Maintainer  : Rudy Matela <rudy@matela.com.br>
 --
diff --git a/src/Test/LeanCheck/Instances/Natural.hs b/src/Test/LeanCheck/Instances/Natural.hs
--- a/src/Test/LeanCheck/Instances/Natural.hs
+++ b/src/Test/LeanCheck/Instances/Natural.hs
@@ -1,6 +1,6 @@
 -- |
 -- Module      : Test.LeanCheck.Instances.Natural
--- Copyright   : (c) 2018 Rudy Matela
+-- Copyright   : (c) 2018-2022 Rudy Matela
 -- License     : 3-Clause BSD  (see the file LICENSE)
 -- Maintainer  : Rudy Matela <rudy@matela.com.br>
 --
diff --git a/src/Test/LeanCheck/Instances/Text.hs b/src/Test/LeanCheck/Instances/Text.hs
--- a/src/Test/LeanCheck/Instances/Text.hs
+++ b/src/Test/LeanCheck/Instances/Text.hs
@@ -1,6 +1,6 @@
 -- |
 -- Module      : Test.LeanCheck.Instances.Text
--- Copyright   : (c) 2018 Rudy Matela
+-- Copyright   : (c) 2018-2022 Rudy Matela
 -- License     : 3-Clause BSD  (see the file LICENSE)
 -- Maintainer  : Rudy Matela <rudy@matela.com.br>
 --
diff --git a/src/Test/LeanCheck/Instances/Time.hs b/src/Test/LeanCheck/Instances/Time.hs
--- a/src/Test/LeanCheck/Instances/Time.hs
+++ b/src/Test/LeanCheck/Instances/Time.hs
@@ -1,6 +1,6 @@
 -- |
 -- Module      : Test.LeanCheck.Instances.Time
--- Copyright   : (c) 2019 Rudy Matela
+-- Copyright   : (c) 2019-2022 Rudy Matela
 -- License     : 3-Clause BSD  (see the file LICENSE)
 -- Maintainer  : Rudy Matela <rudy@matela.com.br>
 --
diff --git a/src/Test/LeanCheck/Instances/Void.hs b/src/Test/LeanCheck/Instances/Void.hs
new file mode 100644
--- /dev/null
+++ b/src/Test/LeanCheck/Instances/Void.hs
@@ -0,0 +1,18 @@
+-- |
+-- Module      : Test.LeanCheck.Instances.Void
+-- Copyright   : (c) 2022 Rudy Matela
+-- License     : 3-Clause BSD  (see the file LICENSE)
+-- Maintainer  : Rudy Matela <rudy@matela.com.br>
+--
+-- Declares a 'Listable' 'Void' instance.
+{-# LANGUAGE CPP #-}
+module Test.LeanCheck.Instances.Void () where
+
+#if __GLASGOW_HASKELL__ < 710
+-- the Void type is not available
+#else
+import Data.Void (Void)
+import Test.LeanCheck
+
+instance Listable Void where  list  =  []
+#endif
diff --git a/src/Test/LeanCheck/WithInstances.hs b/src/Test/LeanCheck/WithInstances.hs
--- a/src/Test/LeanCheck/WithInstances.hs
+++ b/src/Test/LeanCheck/WithInstances.hs
@@ -1,6 +1,6 @@
 -- |
 -- Module      : Test.LeanCheck.WithInstances
--- Copyright   : (c) 2018-2019 Rudy Matela
+-- Copyright   : (c) 2018-2022 Rudy Matela
 -- License     : 3-Clause BSD  (see the file LICENSE)
 -- Maintainer  : Rudy Matela <rudy@matela.com.br>
 --
diff --git a/stack.yaml b/stack.yaml
--- a/stack.yaml
+++ b/stack.yaml
@@ -1,7 +1,7 @@
-resolver: lts-15.5 # or ghc-8.8.3
+resolver: lts-19.19 # or ghc-9.0.2
 
 packages:
 - .
 
 extra-deps:
-- leancheck-0.9.2
+- leancheck-1.0.0
diff --git a/test/main.hs b/test/main.hs
--- a/test/main.hs
+++ b/test/main.hs
@@ -1,4 +1,4 @@
--- Copyright (c) 2015-2018 Rudy Matela.
+-- Copyright (c) 2015-2022 Rudy Matela.
 -- Distributed under the 3-Clause BSD licence (see the file LICENSE).
 import System.Exit (exitFailure)
 import Data.List (elemIndices)
diff --git a/test/sdist b/test/sdist
--- a/test/sdist
+++ b/test/sdist
@@ -2,7 +2,7 @@
 #
 # test/sdist: tests the package generated by "cabal sdist".
 #
-# Copyright (c) 2015-2020 Rudy Matela.
+# Copyright (c) 2015-2021 Rudy Matela.
 # Distributed under the 3-Clause BSD licence.
 
 set -xe
diff --git a/test/text.hs b/test/text.hs
--- a/test/text.hs
+++ b/test/text.hs
@@ -1,4 +1,4 @@
--- Copyright (c) 2015-2018 Rudy Matela.
+-- Copyright (c) 2015-2022 Rudy Matela.
 -- Distributed under the 3-Clause BSD licence (see the file LICENSE).
 import System.Exit (exitFailure)
 import Data.List (elemIndices)