diff --git a/.gitignore b/.gitignore
--- a/.gitignore
+++ b/.gitignore
@@ -3,6 +3,7 @@
 .stack-work
 idx/
 dist/
+dist-newstyle/
 log/
 *.swp
 *.swo
diff --git a/.travis.yml b/.travis.yml
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,6 +1,6 @@
 # .travis.yml file for Express
 #
-# Copyright:   (c) 2017-2019 Rudy Matela
+# Copyright:   (c) 2017-2020 Rudy Matela
 # License:     3-Clause BSD  (see the file LICENSE)
 # Maintainer:  Rudy Matela <rudy@matela.com.br>
 
@@ -22,6 +22,9 @@
 - 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
@@ -31,36 +34,39 @@
 - 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
+- cabal install leancheck || cabal install leancheck --lib
 
 script:
 - make && make test
 - make haddock
 - make test-sdist
 - cabal test main --ghc-option=-O0
-- stack $STACKR --no-terminal --skip-ghc-check test express:test:main --ghc-options=-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
+    env:                   GHCVER=head         CABALVER=head   STACKVER=nightly-2020-03-28
     addons: {apt: {packages: [ghc-head,   cabal-install-head], 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=8.6.1        CABALVER=2.4
-    addons: {apt: {packages: [ghc-8.6.1,  cabal-install-2.4],  sources: hvr-ghc}}
+    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
+    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
+    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
+    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   STACK_YAML=stack-lts-11.yaml
+    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'
@@ -70,10 +76,12 @@
     - 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
     script:
     - make && make test
     - make haddock HADDOCKFLAGS=
+    - make test-sdist
     - cabal test
diff --git a/LICENSE b/LICENSE
--- a/LICENSE
+++ b/LICENSE
@@ -1,4 +1,4 @@
-Copyright (c) 2019, Rudy Matela
+Copyright (c) 2019-2020, Rudy Matela
 
 All rights reserved.
 
diff --git a/Makefile b/Makefile
--- a/Makefile
+++ b/Makefile
@@ -32,6 +32,8 @@
 GHCIMPORTDIRS = src:test
 GHCFLAGS = -O2 $(shell grep -q "Arch Linux" /etc/lsb-release && echo -dynamic)
 HADDOCKFLAGS = --no-print-missing-docs
+HUGSIMPORTDIRS = .:./src:./test:./etc/hugs-backports:/usr/lib/hugs/packages/*
+HUGSFLAGS = -98 -h32M
 RUNPARAMETERS =
 LIB_DEPS = base template-haskell
 
diff --git a/README.md b/README.md
--- a/README.md
+++ b/README.md
@@ -17,7 +17,7 @@
 building, evaluating, comparing, folding, canonicalizing and matching
 [`Expr`]s.  See [Express's Haddock documentation] for more details.
 
-This library has been used successfully in the implementation of
+This library has been used in the implementation of
 [Speculate] and [Extrapolate].
 
 
@@ -33,6 +33,10 @@
 Basics
 ------
 
+To import `Express` just:
+
+	> import Data.Express
+
 For types that are [`Show`] instances,
 we can use [`val`] to encode values as [`Expr`]s.
 
@@ -137,7 +141,7 @@
 Example 3: u-Extrapolate
 ------------------------
 
-[u-Extrapolate] is a property-based testing property-based testing library
+[u-Extrapolate] is a property-based testing library
 capable of generalizing counter-examples.  It's implementation has under 40
 lines of code.  Besides, using Express to encode expressions, it uses
 [LeanCheck] for generating test values.
@@ -338,8 +342,10 @@
 
 [Express's Haddock documentation]: https://hackage.haskell.org/package/express/docs/Data-Express.html
 
-[`Expr`]:         https://hackage.haskell.org/package/express/docs/Data-Express.html#t:val
+[`Expr`]:         https://hackage.haskell.org/package/express/docs/Data-Express.html#t:Expr
 [`val`]:          https://hackage.haskell.org/package/express/docs/Data-Express.html#v:val
+[`value`]:        https://hackage.haskell.org/package/express/docs/Data-Express.html#v:value
+[`eval`]:         https://hackage.haskell.org/package/express/docs/Data-Express.html#v:eval
 [`evaluate`]:     https://hackage.haskell.org/package/express/docs/Data-Express.html#v:evaluate
 [`:$`]:           https://hackage.haskell.org/package/express-0.1.1/docs/Data-Express.html#v::-36-
 [`$$`]:           https://hackage.haskell.org/package/express/docs/Data-Express.html#v:-36--36-
diff --git a/eg/u-extrapolate.hs b/eg/u-extrapolate.hs
--- a/eg/u-extrapolate.hs
+++ b/eg/u-extrapolate.hs
@@ -1,6 +1,6 @@
 -- u-extrapolate.hs -- micro Extrapolate / Extrapolite
 --
--- Copyright (c) 2019 Rudy Matela.
+-- Copyright (c) 2019-2020 Rudy Matela.
 -- Distributed under the 3-Clause BSD licence (see the file LICENSE).
 --
 -- A small property-based testing library capable of generalizing
diff --git a/eg/u-speculate.hs b/eg/u-speculate.hs
--- a/eg/u-speculate.hs
+++ b/eg/u-speculate.hs
@@ -1,6 +1,6 @@
 -- u-extrapolate.hs -- micro Speculate / Speculite
 --
--- Copyright (c) 2019 Rudy Matela.
+-- Copyright (c) 2019-2020 Rudy Matela.
 -- Distributed under the 3-Clause BSD licence (see the file LICENSE).
 --
 -- A small library capable of conjecturing laws about Haskell functions
diff --git a/express.cabal b/express.cabal
--- a/express.cabal
+++ b/express.cabal
@@ -1,6 +1,6 @@
 -- Cabal file for express
 name: express
-version: 0.1.2
+version: 0.1.3
 synopsis: Dynamically-typed expressions involving applications and variables.
 description:
   Express is a library for manipulating dynamically typed Haskell expressions.
@@ -31,10 +31,10 @@
                   , mk/haskell.mk
                   , mk/ghcdeps
                   , mk/haddock-i
+                  , mk/install-on
                   , mk/All.hs
                   , mk/Toplibs.hs
                   , stack.yaml
-                  , stack-lts-11.yaml
                   , test/sdist
                   , test/model/bench/*.out
                   , test/model/eg/*.out
@@ -42,7 +42,8 @@
                   , bench/runtime/zero/versions
                   , bench/runtime/zero/bench/*.runtime
                   , bench/runtime/zero/eg/*.runtime
-tested-with: GHC==8.6
+tested-with: GHC==8.8
+           , GHC==8.6
            , GHC==8.4
            , GHC==8.2
            , GHC==8.0
@@ -57,7 +58,7 @@
 source-repository this
   type:           git
   location:       https://github.com/rudymatela/express
-  tag:            v0.1.2
+  tag:            v0.1.3
 
 library
   exposed-modules:     Data.Express
@@ -87,7 +88,7 @@
   main-is:             main.hs
   hs-source-dirs:      test
   other-modules:       Test, Test.ListableExpr
-  build-depends:       base >= 4 && < 5, express, leancheck >= 0.8
+  build-depends:       base >= 4 && < 5, express, leancheck >= 0.9.3
   default-language:    Haskell2010
 
 test-suite core
@@ -95,7 +96,7 @@
   main-is:             core.hs
   hs-source-dirs:      test
   other-modules:       Test, Test.ListableExpr
-  build-depends:       base >= 4 && < 5, express, leancheck >= 0.8
+  build-depends:       base >= 4 && < 5, express, leancheck >= 0.9.3
   default-language:    Haskell2010
 
 test-suite canon
@@ -103,7 +104,7 @@
   main-is:             canon.hs
   hs-source-dirs:      test
   other-modules:       Test, Test.ListableExpr
-  build-depends:       base >= 4 && < 5, express, leancheck >= 0.8
+  build-depends:       base >= 4 && < 5, express, leancheck >= 0.9.3
   default-language:    Haskell2010
 
 test-suite hole
@@ -111,7 +112,7 @@
   main-is:             hole.hs
   hs-source-dirs:      test
   other-modules:       Test, Test.ListableExpr
-  build-depends:       base >= 4 && < 5, express, leancheck >= 0.8
+  build-depends:       base >= 4 && < 5, express, leancheck >= 0.9.3
   default-language:    Haskell2010
 
 test-suite match
@@ -119,7 +120,7 @@
   main-is:             match.hs
   hs-source-dirs:      test
   other-modules:       Test, Test.ListableExpr
-  build-depends:       base >= 4 && < 5, express, leancheck >= 0.8
+  build-depends:       base >= 4 && < 5, express, leancheck >= 0.9.3
   default-language:    Haskell2010
 
 test-suite map
@@ -127,7 +128,7 @@
   main-is:             map.hs
   hs-source-dirs:      test
   other-modules:       Test, Test.ListableExpr
-  build-depends:       base >= 4 && < 5, express, leancheck >= 0.8
+  build-depends:       base >= 4 && < 5, express, leancheck >= 0.9.3
   default-language:    Haskell2010
 
 test-suite fixtures
@@ -135,7 +136,7 @@
   main-is:             fixtures.hs
   hs-source-dirs:      test
   other-modules:       Test, Test.ListableExpr
-  build-depends:       base >= 4 && < 5, express, leancheck >= 0.8
+  build-depends:       base >= 4 && < 5, express, leancheck >= 0.9.3
   default-language:    Haskell2010
 
 test-suite instances
@@ -143,7 +144,7 @@
   main-is:             instances.hs
   hs-source-dirs:      test
   other-modules:       Test, Test.ListableExpr
-  build-depends:       base >= 4 && < 5, express, leancheck >= 0.8
+  build-depends:       base >= 4 && < 5, express, leancheck >= 0.9.3
   default-language:    Haskell2010
 
 test-suite express-instances
@@ -151,7 +152,7 @@
   main-is:             express.hs
   hs-source-dirs:      test
   other-modules:       Test, Test.ListableExpr
-  build-depends:       base >= 4 && < 5, express, leancheck >= 0.8
+  build-depends:       base >= 4 && < 5, express, leancheck >= 0.9.3
   default-language:    Haskell2010
 
 test-suite express-derive
@@ -159,7 +160,7 @@
   main-is:             express-derive.hs
   hs-source-dirs:      test
   other-modules:       Test, Test.ListableExpr
-  build-depends:       base >= 4 && < 5, express, leancheck >= 0.8
+  build-depends:       base >= 4 && < 5, express, leancheck >= 0.9.3
   default-language:    Haskell2010
 
 test-suite ord
@@ -167,7 +168,7 @@
   main-is:             ord.hs
   hs-source-dirs:      test
   other-modules:       Test, Test.ListableExpr
-  build-depends:       base >= 4 && < 5, express, leancheck >= 0.8
+  build-depends:       base >= 4 && < 5, express, leancheck >= 0.9.3
   default-language:    Haskell2010
 
 test-suite listable
@@ -175,7 +176,7 @@
   main-is:             listable.hs
   hs-source-dirs:      test
   other-modules:       Test, Test.ListableExpr
-  build-depends:       base >= 4 && < 5, express, leancheck >= 0.8
+  build-depends:       base >= 4 && < 5, express, leancheck >= 0.9.3
   default-language:    Haskell2010
 
 test-suite name
@@ -183,7 +184,7 @@
   main-is:             name.hs
   hs-source-dirs:      test
   other-modules:       Test, Test.ListableExpr
-  build-depends:       base >= 4 && < 5, express, leancheck >= 0.8
+  build-depends:       base >= 4 && < 5, express, leancheck >= 0.9.3
   default-language:    Haskell2010
 
 test-suite name-derive
@@ -191,7 +192,7 @@
   main-is:             name-derive.hs
   hs-source-dirs:      test
   other-modules:       Test, Test.ListableExpr
-  build-depends:       base >= 4 && < 5, express, leancheck >= 0.8
+  build-depends:       base >= 4 && < 5, express, leancheck >= 0.9.3
   default-language:    Haskell2010
 
 test-suite fold
@@ -199,7 +200,7 @@
   main-is:             fold.hs
   hs-source-dirs:      test
   other-modules:       Test, Test.ListableExpr
-  build-depends:       base >= 4 && < 5, express, leancheck >= 0.8
+  build-depends:       base >= 4 && < 5, express, leancheck >= 0.9.3
   default-language:    Haskell2010
 
 test-suite show
@@ -207,7 +208,7 @@
   main-is:             show.hs
   hs-source-dirs:      test
   other-modules:       Test, Test.ListableExpr
-  build-depends:       base >= 4 && < 5, express, leancheck >= 0.8
+  build-depends:       base >= 4 && < 5, express, leancheck >= 0.9.3
   default-language:    Haskell2010
 
 test-suite utils
@@ -215,7 +216,7 @@
   main-is:             utils.hs
   hs-source-dirs:      test
   other-modules:       Test, Test.ListableExpr
-  build-depends:       base >= 4 && < 5, express, leancheck >= 0.8
+  build-depends:       base >= 4 && < 5, express, leancheck >= 0.9.3
   default-language:    Haskell2010
 
 benchmark compare
@@ -223,7 +224,7 @@
   main-is:             compare.hs
   hs-source-dirs:      bench, test
   other-modules:       Test, Test.ListableExpr
-  build-depends:       base >= 4 && < 5, express, leancheck >= 0.8
+  build-depends:       base >= 4 && < 5, express, leancheck >= 0.9.3
   default-language:    Haskell2010
 
 benchmark pairs
@@ -231,7 +232,7 @@
   main-is:             pairs.hs
   hs-source-dirs:      bench, test
   other-modules:       Test, Test.ListableExpr
-  build-depends:       base >= 4 && < 5, express, leancheck >= 0.8
+  build-depends:       base >= 4 && < 5, express, leancheck >= 0.9.3
   default-language:    Haskell2010
 
 benchmark tiers
@@ -239,19 +240,19 @@
   main-is:             tiers.hs
   hs-source-dirs:      bench, test
   other-modules:       Test, Test.ListableExpr
-  build-depends:       base >= 4 && < 5, express, leancheck >= 0.8
+  build-depends:       base >= 4 && < 5, express, leancheck >= 0.9.3
   default-language:    Haskell2010
 
 benchmark u-extrapolate
   type:                exitcode-stdio-1.0
   main-is:             u-extrapolate.hs
   hs-source-dirs:      eg
-  build-depends:       base >= 4 && < 5, express, leancheck >= 0.8
+  build-depends:       base >= 4 && < 5, express, leancheck >= 0.9.3
   default-language:    Haskell2010
 
 benchmark u-speculate
   type:                exitcode-stdio-1.0
   main-is:             u-speculate.hs
   hs-source-dirs:      eg
-  build-depends:       base >= 4 && < 5, express, leancheck >= 0.8
+  build-depends:       base >= 4 && < 5, express, leancheck >= 0.9.3
   default-language:    Haskell2010
diff --git a/mk/depend.mk b/mk/depend.mk
--- a/mk/depend.mk
+++ b/mk/depend.mk
@@ -165,11 +165,6 @@
   src/Data/Express/Canon.hs \
   src/Data/Express/Basic.hs \
   mk/Toplibs.hs
-Setup.o: \
-  Setup.hs
-Setup: \
-  Setup.hs \
-  mk/toplibs
 src/Data/Express/Basic.o: \
   src/Data/Express/Utils/Typeable.hs \
   src/Data/Express/Utils/String.hs \
@@ -307,7 +302,8 @@
 src/Data/Express/Utils/TH.o: \
   src/Data/Express/Utils/TH.hs
 src/Data/Express/Utils/Typeable.o: \
-  src/Data/Express/Utils/Typeable.hs
+  src/Data/Express/Utils/Typeable.hs \
+  src/Data/Express/Utils/List.hs
 test/canon.o: \
   test/Test.hs \
   test/Test/ListableExpr.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) 2015-2019 Rudy Matela.
+# Copyright (c) 2015-2020 Rudy Matela.
 # Distributed under the 3-Clause BSD licence.
 #
 # From a list of files provided on standard input,
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) 2015-2019 Rudy Matela.
+# Copyright (c) 2015-2020 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) 2015-2019 Rudy Matela.
+# Copyright (c) 2015-2020 Rudy Matela.
 # Distributed under the 3-Clause BSD licence.
 #
 # You can optionally configure the "Configuration variables" below in your main
@@ -39,7 +39,7 @@
 # ALL_HSS: all Haskell files
 # You can override ALL/LIB_HSS in your main Makefile
 LIST_LIB_HSS ?= find src -name "*.hs"
-LIST_ALL_HSS ?= find \( -path "./dist" -o -path "./.stack-work" \) -prune \
+LIST_ALL_HSS ?= find \( -path "./dist*" -o -path "./.stack-work" -o -path "./Setup.hs" \) -prune \
                      -o -name "*.*hs" -print
 LIB_HSS ?= $(shell $(LIST_LIB_HSS))
 ALL_HSS ?= $(shell $(LIST_ALL_HSS))
@@ -97,7 +97,7 @@
 haddock: doc/index.html
 
 clean-haddock:
-	rm -f doc/*.{html,css,js,png,gif,json} doc/src/*.{html,css,js} README.html
+	rm -f doc/*.{html,css,js,png,gif,json} doc/src/* README.html
 
 upload-haddock:
 	@echo "use \`cabal upload -d' instead"
diff --git a/mk/install-on b/mk/install-on
new file mode 100644
--- /dev/null
+++ b/mk/install-on
@@ -0,0 +1,30 @@
+#!/bin/bash
+#
+# mk/install-on: install or updates the mk folder on a Haskell project
+#
+# usage: ./mk/install-on path/to/project
+#
+# This assumes a few things:
+#
+# * tests are stored in a "test/" folder
+# * sources are stored in a "src/" folder
+set -e
+
+errxit() {
+	echo "$@" > /dev/stderr
+	exit 1
+}
+
+src=`dirname $0`/..
+dst="$1"
+
+[ -n "$dst" ] || errxit "destination folder not provided"
+
+mkdir -p $dst/mk
+mkdir -p $dst/test
+
+cp $src/mk/ghcdeps    $dst/mk/ghcdeps
+cp $src/mk/haddock-i  $dst/mk/haddock-i
+cp $src/mk/haskell.mk $dst/mk/haskell.mk
+cp $src/mk/install-on $dst/mk/install-on
+cp $src/test/sdist    $dst/test/sdist
diff --git a/src/Data/Express.hs b/src/Data/Express.hs
--- a/src/Data/Express.hs
+++ b/src/Data/Express.hs
@@ -1,6 +1,6 @@
 -- |
 -- Module      : Data.Express
--- Copyright   : (c) 2019 Rudy Matela
+-- Copyright   : (c) 2019-2020 Rudy Matela
 -- License     : 3-Clause BSD  (see the file LICENSE)
 -- Maintainer  : Rudy Matela <rudy@matela.com.br>
 --
diff --git a/src/Data/Express/Basic.hs b/src/Data/Express/Basic.hs
--- a/src/Data/Express/Basic.hs
+++ b/src/Data/Express/Basic.hs
@@ -1,6 +1,6 @@
 -- |
 -- Module      : Data.Express.Basic
--- Copyright   : (c) 2019 Rudy Matela
+-- Copyright   : (c) 2019-2020 Rudy Matela
 -- License     : 3-Clause BSD  (see the file LICENSE)
 -- Maintainer  : Rudy Matela <rudy@matela.com.br>
 --
diff --git a/src/Data/Express/Canon.hs b/src/Data/Express/Canon.hs
--- a/src/Data/Express/Canon.hs
+++ b/src/Data/Express/Canon.hs
@@ -1,6 +1,6 @@
 -- |
 -- Module      : Data.Express.Canon
--- Copyright   : (c) 2019 Rudy Matela
+-- Copyright   : (c) 2019-2020 Rudy Matela
 -- License     : 3-Clause BSD  (see the file LICENSE)
 -- Maintainer  : Rudy Matela <rudy@matela.com.br>
 --
diff --git a/src/Data/Express/Core.hs b/src/Data/Express/Core.hs
--- a/src/Data/Express/Core.hs
+++ b/src/Data/Express/Core.hs
@@ -1,6 +1,6 @@
 -- |
 -- Module      : Data.Express.Core
--- Copyright   : (c) 2019 Rudy Matela
+-- Copyright   : (c) 2019-2020 Rudy Matela
 -- License     : 3-Clause BSD  (see the file LICENSE)
 -- Maintainer  : Rudy Matela <rudy@matela.com.br>
 --
diff --git a/src/Data/Express/Express.hs b/src/Data/Express/Express.hs
--- a/src/Data/Express/Express.hs
+++ b/src/Data/Express/Express.hs
@@ -1,6 +1,6 @@
 -- |
 -- Module      : Data.Express.Express
--- Copyright   : (c) 2019 Rudy Matela
+-- Copyright   : (c) 2019-2020 Rudy Matela
 -- License     : 3-Clause BSD  (see the file LICENSE)
 -- Maintainer  : Rudy Matela <rudy@matela.com.br>
 --
diff --git a/src/Data/Express/Express/Derive.hs b/src/Data/Express/Express/Derive.hs
--- a/src/Data/Express/Express/Derive.hs
+++ b/src/Data/Express/Express/Derive.hs
@@ -1,7 +1,7 @@
 {-# LANGUAGE TemplateHaskell, CPP #-}
 -- |
 -- Module      : Data.Express.Express.Derive
--- Copyright   : (c) 2019 Rudy Matela
+-- Copyright   : (c) 2019-2020 Rudy Matela
 -- License     : 3-Clause BSD  (see the file LICENSE)
 -- Maintainer  : Rudy Matela <rudy@matela.com.br>
 --
diff --git a/src/Data/Express/Fixtures.hs b/src/Data/Express/Fixtures.hs
--- a/src/Data/Express/Fixtures.hs
+++ b/src/Data/Express/Fixtures.hs
@@ -1,6 +1,6 @@
 -- |
 -- Module      : Data.Express.Fixtures
--- Copyright   : (c) 2019 Rudy Matela
+-- Copyright   : (c) 2019-2020 Rudy Matela
 -- License     : 3-Clause BSD  (see the file LICENSE)
 -- Maintainer  : Rudy Matela <rudy@matela.com.br>
 --
diff --git a/src/Data/Express/Fold.hs b/src/Data/Express/Fold.hs
--- a/src/Data/Express/Fold.hs
+++ b/src/Data/Express/Fold.hs
@@ -1,6 +1,6 @@
 -- |
 -- Module      : Data.Express.Fold
--- Copyright   : (c) 2019 Rudy Matela
+-- Copyright   : (c) 2019-2020 Rudy Matela
 -- License     : 3-Clause BSD  (see the file LICENSE)
 -- Maintainer  : Rudy Matela <rudy@matela.com.br>
 --
diff --git a/src/Data/Express/Hole.hs b/src/Data/Express/Hole.hs
--- a/src/Data/Express/Hole.hs
+++ b/src/Data/Express/Hole.hs
@@ -1,6 +1,6 @@
 -- |
 -- Module      : Data.Express.Hole
--- Copyright   : (c) 2019 Rudy Matela
+-- Copyright   : (c) 2019-2020 Rudy Matela
 -- License     : 3-Clause BSD  (see the file LICENSE)
 -- Maintainer  : Rudy Matela <rudy@matela.com.br>
 --
diff --git a/src/Data/Express/Instances.hs b/src/Data/Express/Instances.hs
--- a/src/Data/Express/Instances.hs
+++ b/src/Data/Express/Instances.hs
@@ -1,6 +1,6 @@
 -- |
 -- Module      : Data.Express.Instances
--- Copyright   : (c) 2019 Rudy Matela
+-- Copyright   : (c) 2019-2020 Rudy Matela
 -- License     : 3-Clause BSD  (see the file LICENSE)
 -- Maintainer  : Rudy Matela <rudy@matela.com.br>
 --
diff --git a/src/Data/Express/Map.hs b/src/Data/Express/Map.hs
--- a/src/Data/Express/Map.hs
+++ b/src/Data/Express/Map.hs
@@ -1,6 +1,6 @@
 -- |
 -- Module      : Data.Express.Map
--- Copyright   : (c) 2019 Rudy Matela
+-- Copyright   : (c) 2019-2020 Rudy Matela
 -- License     : 3-Clause BSD  (see the file LICENSE)
 -- Maintainer  : Rudy Matela <rudy@matela.com.br>
 --
diff --git a/src/Data/Express/Match.hs b/src/Data/Express/Match.hs
--- a/src/Data/Express/Match.hs
+++ b/src/Data/Express/Match.hs
@@ -1,6 +1,6 @@
 -- |
 -- Module      : Data.Express.Match
--- Copyright   : (c) 2019 Rudy Matela
+-- Copyright   : (c) 2019-2020 Rudy Matela
 -- License     : 3-Clause BSD  (see the file LICENSE)
 -- Maintainer  : Rudy Matela <rudy@matela.com.br>
 --
diff --git a/src/Data/Express/Name.hs b/src/Data/Express/Name.hs
--- a/src/Data/Express/Name.hs
+++ b/src/Data/Express/Name.hs
@@ -1,6 +1,6 @@
 -- |
 -- Module      : Data.Express.Name
--- Copyright   : (c) 2019 Rudy Matela
+-- Copyright   : (c) 2019-2020 Rudy Matela
 -- License     : 3-Clause BSD  (see the file LICENSE)
 -- Maintainer  : Rudy Matela <rudy@matela.com.br>
 --
diff --git a/src/Data/Express/Name/Derive.hs b/src/Data/Express/Name/Derive.hs
--- a/src/Data/Express/Name/Derive.hs
+++ b/src/Data/Express/Name/Derive.hs
@@ -1,7 +1,7 @@
 {-# LANGUAGE TemplateHaskell, CPP #-}
 -- |
 -- Module      : Data.Express.Name.Derive
--- Copyright   : (c) 2019 Rudy Matela
+-- Copyright   : (c) 2019-2020 Rudy Matela
 -- License     : 3-Clause BSD  (see the file LICENSE)
 -- Maintainer  : Rudy Matela <rudy@matela.com.br>
 --
diff --git a/src/Data/Express/Utils/List.hs b/src/Data/Express/Utils/List.hs
--- a/src/Data/Express/Utils/List.hs
+++ b/src/Data/Express/Utils/List.hs
@@ -1,6 +1,6 @@
 -- |
 -- Module      : Data.Express.Utils.List
--- Copyright   : (c) 2019 Rudy Matela
+-- Copyright   : (c) 2019-2020 Rudy Matela
 -- License     : 3-Clause BSD  (see the file LICENSE)
 -- Maintainer  : Rudy Matela <rudy@matela.com.br>
 --
diff --git a/src/Data/Express/Utils/String.hs b/src/Data/Express/Utils/String.hs
--- a/src/Data/Express/Utils/String.hs
+++ b/src/Data/Express/Utils/String.hs
@@ -1,6 +1,6 @@
 -- |
 -- Module      : Data.Express.Utils.String
--- Copyright   : (c) 2016-2019 Rudy Matela
+-- Copyright   : (c) 2016-2020 Rudy Matela
 -- License     : 3-Clause BSD  (see the file LICENSE)
 -- Maintainer  : Rudy Matela <rudy@matela.com.br>
 --
diff --git a/src/Data/Express/Utils/TH.hs b/src/Data/Express/Utils/TH.hs
--- a/src/Data/Express/Utils/TH.hs
+++ b/src/Data/Express/Utils/TH.hs
@@ -1,7 +1,7 @@
 {-# LANGUAGE TemplateHaskell, CPP #-}
 -- |
 -- Module      : Data.Express.Name.Derive
--- Copyright   : (c) 2019 Rudy Matela
+-- Copyright   : (c) 2019-2020 Rudy Matela
 -- License     : 3-Clause BSD  (see the file LICENSE)
 -- Maintainer  : Rudy Matela <rudy@matela.com.br>
 --
diff --git a/src/Data/Express/Utils/Typeable.hs b/src/Data/Express/Utils/Typeable.hs
--- a/src/Data/Express/Utils/Typeable.hs
+++ b/src/Data/Express/Utils/Typeable.hs
@@ -1,6 +1,6 @@
 -- |
 -- Module      : Data.Express.Utils.Typeable
--- Copyright   : (c) 2016-2019 Rudy Matela
+-- Copyright   : (c) 2016-2020 Rudy Matela
 -- License     : 3-Clause BSD  (see the file LICENSE)
 -- Maintainer  : Rudy Matela <rudy@matela.com.br>
 --
diff --git a/stack-lts-11.yaml b/stack-lts-11.yaml
deleted file mode 100644
--- a/stack-lts-11.yaml
+++ /dev/null
@@ -1,17 +0,0 @@
-# stack.yaml docs:
-# https://docs.haskellstack.org/en/stable/yaml_configuration/
-
-# resolver: nightly-2015-09-21
-# resolver: ghc-7.10.2
-resolver: lts-11.22
-
-packages:
-- .
-
-extra-deps:
-- leancheck-0.9.1
-- speculate-0.3.5
-
-flags: {}
-
-extra-package-dbs: []
diff --git a/stack.yaml b/stack.yaml
--- a/stack.yaml
+++ b/stack.yaml
@@ -1,15 +1,7 @@
-# stack.yaml docs:
-# https://docs.haskellstack.org/en/stable/yaml_configuration/
-
-# resolver: nightly-2015-09-21
-# resolver: ghc-7.10.2
-resolver: lts-13.6
+resolver: lts-15.5 # or ghc-8.8.3
 
 packages:
 - .
 
-extra-deps: []
-
-flags: {}
-
-extra-package-dbs: []
+extra-deps:
+- leancheck-0.9.3
diff --git a/test/Test.hs b/test/Test.hs
--- a/test/Test.hs
+++ b/test/Test.hs
@@ -1,6 +1,6 @@
 -- |
 -- Module      : Test
--- Copyright   : (c) 2019 Rudy Matela
+-- Copyright   : (c) 2019-2020 Rudy Matela
 -- License     : 3-Clause BSD  (see the file LICENSE)
 -- Maintainer  : Rudy Matela <rudy@matela.com.br>
 --
diff --git a/test/canon.hs b/test/canon.hs
--- a/test/canon.hs
+++ b/test/canon.hs
@@ -1,4 +1,5 @@
--- Copyright (c) 2017-2018 Rudy Matela.  -- Distributed under the 3-Clause BSD licence (see the file LICENSE).
+-- Copyright (c) 2017-2020 Rudy Matela.
+-- Distributed under the 3-Clause BSD licence (see the file LICENSE).
 import Test
 
 main :: IO ()
diff --git a/test/core.hs b/test/core.hs
--- a/test/core.hs
+++ b/test/core.hs
@@ -1,4 +1,5 @@
--- Copyright (c) 2019 Rudy Matela.  -- Distributed under the 3-Clause BSD licence (see the file LICENSE).
+-- Copyright (c) 2019-2020 Rudy Matela.
+-- Distributed under the 3-Clause BSD licence (see the file LICENSE).
 import Test
 
 import Data.Express.Utils.List
diff --git a/test/express-derive.hs b/test/express-derive.hs
--- a/test/express-derive.hs
+++ b/test/express-derive.hs
@@ -1,4 +1,4 @@
--- Copyright (c) 2019 Rudy Matela.
+-- Copyright (c) 2019-2020 Rudy Matela.
 -- Distributed under the 3-Clause BSD licence (see the file LICENSE).
 {-# LANGUAGE TemplateHaskell #-}
 {-# LANGUAGE DeriveDataTypeable #-}
diff --git a/test/express.hs b/test/express.hs
--- a/test/express.hs
+++ b/test/express.hs
@@ -1,4 +1,4 @@
--- Copyright (c) 2019 Rudy Matela.
+-- Copyright (c) 2019-2020 Rudy Matela.
 -- Distributed under the 3-Clause BSD licence (see the file LICENSE).
 {-# LANGUAGE CPP #-}
 import Test
diff --git a/test/fixtures.hs b/test/fixtures.hs
--- a/test/fixtures.hs
+++ b/test/fixtures.hs
@@ -1,4 +1,4 @@
--- Copyright (c) 2017-2018 Rudy Matela.
+-- Copyright (c) 2017-2020 Rudy Matela.
 -- Distributed under the 3-Clause BSD licence (see the file LICENSE).
 import Test
 
diff --git a/test/fold.hs b/test/fold.hs
--- a/test/fold.hs
+++ b/test/fold.hs
@@ -1,4 +1,5 @@
--- Copyright (c) 2019 Rudy Matela.  -- Distributed under the 3-Clause BSD licence (see the file LICENSE).
+-- Copyright (c) 2019-2020 Rudy Matela.
+-- Distributed under the 3-Clause BSD licence (see the file LICENSE).
 import Test
 
 main :: IO ()
diff --git a/test/hole.hs b/test/hole.hs
--- a/test/hole.hs
+++ b/test/hole.hs
@@ -1,4 +1,4 @@
--- Copyright (c) 2019 Rudy Matela.
+-- Copyright (c) 2019-2020 Rudy Matela.
 -- Distributed under the 3-Clause BSD licence (see the file LICENSE).
 import Test
 
diff --git a/test/instances.hs b/test/instances.hs
--- a/test/instances.hs
+++ b/test/instances.hs
@@ -1,4 +1,4 @@
--- Copyright (c) 2017-2019 Rudy Matela.
+-- Copyright (c) 2017-2020 Rudy Matela.
 -- Distributed under the 3-Clause BSD licence (see the file LICENSE).
 {-# LANGUAGE NoMonomorphismRestriction #-} -- ACK!
 import Test
diff --git a/test/listable.hs b/test/listable.hs
--- a/test/listable.hs
+++ b/test/listable.hs
@@ -1,4 +1,4 @@
--- Copyright (c) 2017-2018 Rudy Matela.
+-- Copyright (c) 2017-2020 Rudy Matela.
 -- Distributed under the 3-Clause BSD licence (see the file LICENSE).
 import Test
 
diff --git a/test/main.hs b/test/main.hs
--- a/test/main.hs
+++ b/test/main.hs
@@ -1,4 +1,5 @@
--- Copyright (c) 2019 Rudy Matela.  -- Distributed under the 3-Clause BSD licence (see the file LICENSE).
+-- Copyright (c) 2019-2020 Rudy Matela.
+-- Distributed under the 3-Clause BSD licence (see the file LICENSE).
 import Test
 
 import Data.Express.Utils.List
diff --git a/test/map.hs b/test/map.hs
--- a/test/map.hs
+++ b/test/map.hs
@@ -1,4 +1,4 @@
--- Copyright (c) 2019 Rudy Matela.
+-- Copyright (c) 2019-2020 Rudy Matela.
 -- Distributed under the 3-Clause BSD licence (see the file LICENSE).
 import Test
 import Test.LeanCheck.Function
diff --git a/test/match.hs b/test/match.hs
--- a/test/match.hs
+++ b/test/match.hs
@@ -1,4 +1,4 @@
--- Copyright (c) 2019 Rudy Matela.
+-- Copyright (c) 2019-2020 Rudy Matela.
 -- Distributed under the 3-Clause BSD licence (see the file LICENSE).
 import Test
 
diff --git a/test/name-derive.hs b/test/name-derive.hs
--- a/test/name-derive.hs
+++ b/test/name-derive.hs
@@ -1,4 +1,4 @@
--- Copyright (c) 2019 Rudy Matela.
+-- Copyright (c) 2019-2020 Rudy Matela.
 -- Distributed under the 3-Clause BSD licence (see the file LICENSE).
 {-# LANGUAGE TemplateHaskell #-}
 
diff --git a/test/name.hs b/test/name.hs
--- a/test/name.hs
+++ b/test/name.hs
@@ -1,4 +1,5 @@
--- Copyright (c) 2017-2018 Rudy Matela.  -- Distributed under the 3-Clause BSD licence (see the file LICENSE).
+-- Copyright (c) 2017-2020 Rudy Matela.
+-- Distributed under the 3-Clause BSD licence (see the file LICENSE).
 import Test
 
 import Data.Express.Utils.List
diff --git a/test/ord.hs b/test/ord.hs
--- a/test/ord.hs
+++ b/test/ord.hs
@@ -1,4 +1,5 @@
--- Copyright (c) 2019 Rudy Matela.  -- Distributed under the 3-Clause BSD licence (see the file LICENSE).
+-- Copyright (c) 2019-2020 Rudy Matela.
+-- Distributed under the 3-Clause BSD licence (see the file LICENSE).
 import Test
 
 main :: IO ()
diff --git a/test/sdist b/test/sdist
--- a/test/sdist
+++ b/test/sdist
@@ -2,32 +2,39 @@
 #
 # test/sdist: tests the package generated by "cabal sdist".
 #
-# Copyright (c) 2015-2018 Rudy Matela.
+# Copyright (c) 2015-2020 Rudy Matela.
 # Distributed under the 3-Clause BSD licence.
+
+set -xe
+
 export LC_ALL=C  # consistent sort
+
 pkgver=` cat *.cabal | grep "^version:" | sed -e "s/version: *//"`
 pkgname=`cat *.cabal | grep "^name:"    | sed -e "s/name: *//"`
-pkg=$pkgname-$pkgver
-set -x
-cabal sdist &&
-cd dist &&
-tar -tf $pkg.tar.gz | sort --ignore-case          > ls-cabal-i  &&
-tar -tf $pkg.tar.gz | sort --ignore-case --unique > ls-cabal-iu &&
-diff -rud ls-cabal-i ls-cabal-iu &&
-rm -f ls-cabal ls-cabal-ignore-case &&
-if [ -d ../.git ]
+pkgbase=$pkgname-$pkgver
+
+cabal sdist
+
+# Try to find the package generated by cabal.
+pkg=`find dist* -name $pkgbase.tar.gz`
+[ -f "$pkg" ]
+# If the script fails here, either:
+#   * no package was generated
+#   * there are packages in both dist and dist-newstyle folders.
+
+tmp=`mktemp -d /tmp/test-sdist-XXXXXXXXXX`
+
+# Test if our file is compatible with case-insensitive filesystems.
+tar -tf $pkg | sort --ignore-case          > $tmp/ls-cabal-i
+tar -tf $pkg | sort --ignore-case --unique > $tmp/ls-cabal-iu
+diff -rud $tmp/ls-cabal-i $tmp/ls-cabal-iu
+
+if [ -d .git ]
 then
-	# on git repo, test if files are the same
-	git -C .. ls-files                                      | sort > ls-git   &&
-	tar -tf $pkg.tar.gz | grep -v "/$" | sed -e "s,$pkg/,," | sort > ls-cabal &&
-	diff -rud ls-git ls-cabal &&
-	rm -f ls-git ls-cabal
-else
-	# outside of git repo, test build
-	rm -rf $pkg/ &&
-	tar -xzf $pkg.tar.gz &&
-	cd $pkg/ &&
-	cabal configure --enable-tests --enable-benchmarks &&
-	cabal build &&
-	cabal test
+	# Test if files included by cabal are the same as files tracked in git.
+	git ls-files                                         | sort > $tmp/ls-git
+	tar -tf $pkg | grep -v "/$" | sed -e "s,$pkgbase/,," | sort > $tmp/ls-cabal
+	diff -rud $tmp/ls-git $tmp/ls-cabal
 fi
+
+rm -r $tmp
diff --git a/test/show.hs b/test/show.hs
--- a/test/show.hs
+++ b/test/show.hs
@@ -1,4 +1,5 @@
--- Copyright (c) 2017-2018 Rudy Matela.  -- Distributed under the 3-Clause BSD licence (see the file LICENSE).
+-- Copyright (c) 2017-2020 Rudy Matela.
+-- Distributed under the 3-Clause BSD licence (see the file LICENSE).
 import Test
 
 import Data.Express.Utils.List
diff --git a/test/utils.hs b/test/utils.hs
--- a/test/utils.hs
+++ b/test/utils.hs
@@ -1,4 +1,5 @@
--- Copyright (c) 2017-2018 Rudy Matela.  -- Distributed under the 3-Clause BSD licence (see the file LICENSE).
+-- Copyright (c) 2017-2020 Rudy Matela.
+-- Distributed under the 3-Clause BSD licence (see the file LICENSE).
 import Test
 
 import Data.Express.Utils.List