goldfirere · RyanGlScott · Sep 30, 2025 · Sep 30, 2025
diff --git a/.github/workflows/haskell-ci.yml b/.github/workflows/haskell-ci.yml
@@ -29,6 +29,11 @@ jobs:
     strategy:
       matrix:
         include:
+          - compiler: ghc-9.14.0.20250908
+            compilerKind: ghc
+            compilerVersion: 9.14.0.20250908
+            setup-method: ghcup-prerelease
+            allow-failure: false
           - compiler: ghc-9.12.2
             compilerKind: ghc
             compilerVersion: 9.12.2
@@ -107,8 +112,8 @@ jobs:
           chmod a+x "$HOME/.ghcup/bin/ghcup"
       - name: Install cabal-install
         run: |
-          "$HOME/.ghcup/bin/ghcup" install cabal 3.14.1.1-p1 || (cat "$HOME"/.ghcup/logs/*.* && false)
-          echo "CABAL=$HOME/.ghcup/bin/cabal-3.14.1.1-p1 -vnormal+nowrap" >> "$GITHUB_ENV"
+          "$HOME/.ghcup/bin/ghcup" install cabal 3.16.0.0 || (cat "$HOME"/.ghcup/logs/*.* && false)
+          echo "CABAL=$HOME/.ghcup/bin/cabal-3.16.0.0 -vnormal+nowrap" >> "$GITHUB_ENV"
       - name: Install GHC (GHCup)
         if: matrix.setup-method == 'ghcup'
         run: |
@@ -123,6 +128,21 @@ jobs:
           HCKIND: ${{ matrix.compilerKind }}
           HCNAME: ${{ matrix.compiler }}
           HCVER: ${{ matrix.compilerVersion }}
+      - name: Install GHC (GHCup prerelease)
+        if: matrix.setup-method == 'ghcup-prerelease'
+        run: |
+          "$HOME/.ghcup/bin/ghcup" config add-release-channel prereleases
+          "$HOME/.ghcup/bin/ghcup" install ghc "$HCVER" || (cat "$HOME"/.ghcup/logs/*.* && false)
+          HC=$("$HOME/.ghcup/bin/ghcup" whereis ghc "$HCVER")
+          HCPKG=$(echo "$HC" | sed 's#ghc$#ghc-pkg#')
+          HADDOCK=$(echo "$HC" | sed 's#ghc$#haddock#')
+          echo "HC=$HC" >> "$GITHUB_ENV"
+          echo "HCPKG=$HCPKG" >> "$GITHUB_ENV"
+          echo "HADDOCK=$HADDOCK" >> "$GITHUB_ENV"
+        env:
+          HCKIND: ${{ matrix.compilerKind }}
+          HCNAME: ${{ matrix.compiler }}
+          HCVER: ${{ matrix.compilerVersion }}
       - name: Set PATH and environment variables
         run: |
           echo "$HOME/.cabal/bin" >> $GITHUB_PATH
@@ -133,7 +153,7 @@ jobs:
           echo "HCNUMVER=$HCNUMVER" >> "$GITHUB_ENV"
           echo "ARG_TESTS=--enable-tests" >> "$GITHUB_ENV"
           echo "ARG_BENCH=--enable-benchmarks" >> "$GITHUB_ENV"
-          echo "HEADHACKAGE=false" >> "$GITHUB_ENV"
+          if [ $((HCNUMVER >= 91400)) -ne 0 ] ; then echo "HEADHACKAGE=true" >> "$GITHUB_ENV" ; else echo "HEADHACKAGE=false" >> "$GITHUB_ENV" ; fi
           echo "ARG_COMPILER=--$HCKIND --with-compiler=$HC" >> "$GITHUB_ENV"
         env:
           HCKIND: ${{ matrix.compilerKind }}
@@ -161,6 +181,18 @@ jobs:
           repository hackage.haskell.org
             url: http://hackage.haskell.org/
           EOF
+          if $HEADHACKAGE; then
+          cat >> $CABAL_CONFIG <<EOF
+          repository head.hackage.ghc.haskell.org
+             url: https://ghc.gitlab.haskell.org/head.hackage/
+             secure: True
+             root-keys: 7541f32a4ccca4f97aea3b22f5e593ba2c0267546016b992dfadcd2fe944e55d
+                        26021a13b401500c8eb2761ca95c61f2d625bfef951b939a8124ed12ecf07329
+                        f76d08be13e9a61a377a85e2fb63f4c5435d40f8feb3e12eb05905edb8cdea89
+             key-threshold: 3
+          active-repositories: hackage.haskell.org, head.hackage.ghc.haskell.org:override
+          EOF
+          fi
           cat >> $CABAL_CONFIG <<EOF
           program-default-options
             ghc-options: $GHCJOBS +RTS -M3G -RTS
@@ -191,9 +223,9 @@ jobs:
         run: |
           touch cabal.project
           echo "packages: $GITHUB_WORKSPACE/source/./singletons" >> cabal.project
-          if [ $((HCNUMVER >= 91200)) -ne 0 ] ; then echo "packages: $GITHUB_WORKSPACE/source/./singletons-th" >> cabal.project ; fi
-          if [ $((HCNUMVER >= 91200)) -ne 0 ] ; then echo "packages: $GITHUB_WORKSPACE/source/./singletons-base" >> cabal.project ; fi
-          if [ $((HCNUMVER >= 91200)) -ne 0 ] ; then echo "packages: $GITHUB_WORKSPACE/source/./singletons-base-code-generator" >> cabal.project ; fi
+          if [ $((HCNUMVER >= 91400)) -ne 0 ] ; then echo "packages: $GITHUB_WORKSPACE/source/./singletons-th" >> cabal.project ; fi
+          if [ $((HCNUMVER >= 91400)) -ne 0 ] ; then echo "packages: $GITHUB_WORKSPACE/source/./singletons-base" >> cabal.project ; fi
+          if [ $((HCNUMVER >= 91400)) -ne 0 ] ; then echo "packages: $GITHUB_WORKSPACE/source/./singletons-base-code-generator" >> cabal.project ; fi
           cat cabal.project
       - name: sdist
         run: |
@@ -217,31 +249,34 @@ jobs:
           touch cabal.project
           touch cabal.project.local
           echo "packages: ${PKGDIR_singletons}" >> cabal.project
-          if [ $((HCNUMVER >= 91200)) -ne 0 ] ; then echo "packages: ${PKGDIR_singletons_th}" >> cabal.project ; fi
-          if [ $((HCNUMVER >= 91200)) -ne 0 ] ; then echo "packages: ${PKGDIR_singletons_base}" >> cabal.project ; fi
-          if [ $((HCNUMVER >= 91200)) -ne 0 ] ; then echo "packages: ${PKGDIR_singletons_base_code_generator}" >> cabal.project ; fi
+          if [ $((HCNUMVER >= 91400)) -ne 0 ] ; then echo "packages: ${PKGDIR_singletons_th}" >> cabal.project ; fi
+          if [ $((HCNUMVER >= 91400)) -ne 0 ] ; then echo "packages: ${PKGDIR_singletons_base}" >> cabal.project ; fi
+          if [ $((HCNUMVER >= 91400)) -ne 0 ] ; then echo "packages: ${PKGDIR_singletons_base_code_generator}" >> cabal.project ; fi
           if [ $((HCNUMVER >= 80200)) -ne 0 ] ; then echo "package singletons" >> cabal.project ; fi
           if [ $((HCNUMVER >= 80200)) -ne 0 ] ; then echo "    ghc-options: -Werror=missing-methods -Werror=missing-fields" >> cabal.project ; fi
-          if [ $((HCNUMVER >= 91200)) -ne 0 ] ; then echo "package singletons-th" >> cabal.project ; fi
-          if [ $((HCNUMVER >= 91200)) -ne 0 ] ; then echo "    ghc-options: -Werror=missing-methods -Werror=missing-fields" >> cabal.project ; fi
-          if [ $((HCNUMVER >= 91200)) -ne 0 ] ; then echo "package singletons-base" >> cabal.project ; fi
-          if [ $((HCNUMVER >= 91200)) -ne 0 ] ; then echo "    ghc-options: -Werror=missing-methods -Werror=missing-fields" >> cabal.project ; fi
-          if [ $((HCNUMVER >= 91200)) -ne 0 ] ; then echo "package singletons-base-code-generator" >> cabal.project ; fi
-          if [ $((HCNUMVER >= 91200)) -ne 0 ] ; then echo "    ghc-options: -Werror=missing-methods -Werror=missing-fields" >> cabal.project ; fi
+          if [ $((HCNUMVER >= 91400)) -ne 0 ] ; then echo "package singletons-th" >> cabal.project ; fi
+          if [ $((HCNUMVER >= 91400)) -ne 0 ] ; then echo "    ghc-options: -Werror=missing-methods -Werror=missing-fields" >> cabal.project ; fi
+          if [ $((HCNUMVER >= 91400)) -ne 0 ] ; then echo "package singletons-base" >> cabal.project ; fi
+          if [ $((HCNUMVER >= 91400)) -ne 0 ] ; then echo "    ghc-options: -Werror=missing-methods -Werror=missing-fields" >> cabal.project ; fi
+          if [ $((HCNUMVER >= 91400)) -ne 0 ] ; then echo "package singletons-base-code-generator" >> cabal.project ; fi
+          if [ $((HCNUMVER >= 91400)) -ne 0 ] ; then echo "    ghc-options: -Werror=missing-methods -Werror=missing-fields" >> cabal.project ; fi
           if [ $((HCNUMVER >= 90000)) -ne 0 ] ; then echo "package singletons" >> cabal.project ; fi
           if [ $((HCNUMVER >= 90000)) -ne 0 ] ; then echo "    ghc-options: -Werror=incomplete-patterns -Werror=incomplete-uni-patterns" >> cabal.project ; fi
-          if [ $((HCNUMVER >= 91200)) -ne 0 ] ; then echo "package singletons-th" >> cabal.project ; fi
-          if [ $((HCNUMVER >= 91200)) -ne 0 ] ; then echo "    ghc-options: -Werror=incomplete-patterns -Werror=incomplete-uni-patterns" >> cabal.project ; fi
-          if [ $((HCNUMVER >= 91200)) -ne 0 ] ; then echo "package singletons-base" >> cabal.project ; fi
-          if [ $((HCNUMVER >= 91200)) -ne 0 ] ; then echo "    ghc-options: -Werror=incomplete-patterns -Werror=incomplete-uni-patterns" >> cabal.project ; fi
-          if [ $((HCNUMVER >= 91200)) -ne 0 ] ; then echo "package singletons-base-code-generator" >> cabal.project ; fi
-          if [ $((HCNUMVER >= 91200)) -ne 0 ] ; then echo "    ghc-options: -Werror=incomplete-patterns -Werror=incomplete-uni-patterns" >> cabal.project ; fi
+          if [ $((HCNUMVER >= 91400)) -ne 0 ] ; then echo "package singletons-th" >> cabal.project ; fi
+          if [ $((HCNUMVER >= 91400)) -ne 0 ] ; then echo "    ghc-options: -Werror=incomplete-patterns -Werror=incomplete-uni-patterns" >> cabal.project ; fi
+          if [ $((HCNUMVER >= 91400)) -ne 0 ] ; then echo "package singletons-base" >> cabal.project ; fi
+          if [ $((HCNUMVER >= 91400)) -ne 0 ] ; then echo "    ghc-options: -Werror=incomplete-patterns -Werror=incomplete-uni-patterns" >> cabal.project ; fi
+          if [ $((HCNUMVER >= 91400)) -ne 0 ] ; then echo "package singletons-base-code-generator" >> cabal.project ; fi
+          if [ $((HCNUMVER >= 91400)) -ne 0 ] ; then echo "    ghc-options: -Werror=incomplete-patterns -Werror=incomplete-uni-patterns" >> cabal.project ; fi
           cat >> cabal.project <<EOF
           source-repository-package
             type:     git
             location: https://github.com/goldfirere/th-desugar
             tag:      1c9e884f80d6e8efb5109cb85bb889a12bc9ed8d
           EOF
+          if $HEADHACKAGE; then
+          echo "allow-newer: $($HCPKG list --simple-output | sed -E 's/([a-zA-Z-]+)-[0-9.]+/*:\1,/g')" >> cabal.project
+          fi
           $HCPKG list --simple-output --names-only | perl -ne 'for (split /\s+/) { print "constraints: any.$_ installed\n" unless /^(Cabal|Cabal-syntax|singletons|singletons-base|singletons-base-code-generator|singletons-th)$/; }' >> cabal.project.local
           cat cabal.project
           cat cabal.project.local
@@ -269,12 +304,12 @@ jobs:
         run: |
           cd ${PKGDIR_singletons} || false
           ${CABAL} -vnormal check
-          if [ $((HCNUMVER >= 91200)) -ne 0 ] ; then cd ${PKGDIR_singletons_th} || false ; fi
-          if [ $((HCNUMVER >= 91200)) -ne 0 ] ; then ${CABAL} -vnormal check ; fi
-          if [ $((HCNUMVER >= 91200)) -ne 0 ] ; then cd ${PKGDIR_singletons_base} || false ; fi
-          if [ $((HCNUMVER >= 91200)) -ne 0 ] ; then ${CABAL} -vnormal check ; fi
-          if [ $((HCNUMVER >= 91200)) -ne 0 ] ; then cd ${PKGDIR_singletons_base_code_generator} || false ; fi
-          if [ $((HCNUMVER >= 91200)) -ne 0 ] ; then ${CABAL} -vnormal check ; fi
+          if [ $((HCNUMVER >= 91400)) -ne 0 ] ; then cd ${PKGDIR_singletons_th} || false ; fi
+          if [ $((HCNUMVER >= 91400)) -ne 0 ] ; then ${CABAL} -vnormal check ; fi
+          if [ $((HCNUMVER >= 91400)) -ne 0 ] ; then cd ${PKGDIR_singletons_base} || false ; fi
+          if [ $((HCNUMVER >= 91400)) -ne 0 ] ; then ${CABAL} -vnormal check ; fi
+          if [ $((HCNUMVER >= 91400)) -ne 0 ] ; then cd ${PKGDIR_singletons_base_code_generator} || false ; fi
+          if [ $((HCNUMVER >= 91400)) -ne 0 ] ; then ${CABAL} -vnormal check ; fi
       - name: haddock
         run: |
           $CABAL v2-haddock --disable-documentation $ARG_COMPILER --with-haddock $HADDOCK $ARG_TESTS $ARG_BENCH all

diff --git a/README.md b/README.md
@@ -63,7 +63,7 @@ windows for requirements on the compiler version needed to build each library:
   GHC language extensions, even more so than `singletons` itself. As such, it
   is difficult to maintain support for multiple GHC versions in any given
   release of either library, so they only support the latest major GHC version
-  (currently GHC 9.12).
+  (currently GHC 9.14).
 
 Any code that uses the singleton-generation functionality from `singletons-th`
 or `singletons-base` needs to enable a long list of GHC extensions. This list

diff --git a/cabal.haskell-ci b/cabal.haskell-ci
@@ -6,8 +6,6 @@ jobs-selection:         any
 haddock-components:     libs
 -- Needed to avoid https://github.com/haskell/cabal/issues/9917
 installed:              +all -Cabal -Cabal-syntax
--- Work around https://github.com/haskell-CI/haskell-ci/issues/766
-cabal-install-version:  3.14.1.1
 -- -Wunused-packages mistakenly flags some of singletons-base-test-suite's
 -- dependencies as unused.
 error-unused-packages:  False
diff --git a/singletons-base-code-generator/CHANGES.md b/singletons-base-code-generator/CHANGES.md
@@ -1,6 +1,10 @@
 Changelog for the `singletons-base-code-generator` project
 ==========================================================
 
+next [????.??.??]
+-----------------
+* Require building with GHC 9.14.
+
 0.1 [2024.12.11]
 ----------------
 * Initial release.
diff --git a/singletons-base-code-generator/singletons-base-code-generator.cabal b/singletons-base-code-generator/singletons-base-code-generator.cabal
@@ -8,7 +8,7 @@ author:         Ryan Scott <ryan.gl.scott@gmail.com>
 maintainer:     Ryan Scott <ryan.gl.scott@gmail.com>
 bug-reports:    https://github.com/goldfirere/singletons/issues
 stability:      experimental
-tested-with:    GHC == 9.12.2
+tested-with:    GHC == 9.14.1
 extra-doc-files:    CHANGES.md
 extra-source-files: README.md
 license:        BSD-3-Clause
@@ -38,6 +38,6 @@ executable singletons-base-code-generator
   ghc-options:        -Wall -Wcompat -threaded
   default-language:   GHC2021
   main-is:            SingletonsBaseCodeGenerator.hs
-  build-depends:      base >= 4.21 && < 4.22,
+  build-depends:      base >= 4.22 && < 4.23,
                       directory >= 1.2 && < 1.4,
                       filepath >= 1.3 && < 1.6
diff --git a/singletons-base/CHANGES.md b/singletons-base/CHANGES.md
@@ -1,6 +1,10 @@
 Changelog for the `singletons-base` project
 ===========================================
 
+next [????.??.??]
+-----------------
+* Require building with GHC 9.14.
+
 3.5 [2024.12.11]
 ----------------
 * Require building with GHC 9.12.

diff --git a/singletons-base/README.md b/singletons-base/README.md
@@ -18,7 +18,7 @@ that code with `singletons-base`.
 
 `singletons-base` uses code that relies on bleeding-edge GHC language
 extensions. As such, `singletons-base` only supports the latest major version
-of GHC (currently GHC 9.12). For more information,
+of GHC (currently GHC 9.14). For more information,
 consult the `singletons`
 [`README`](https://github.com/goldfirere/singletons/blob/master/README.md).
 

diff --git a/singletons-base/singletons-base.cabal b/singletons-base/singletons-base.cabal
@@ -8,7 +8,7 @@ author:         Richard Eisenberg <rae@cs.brynmawr.edu>, Jan Stolarek <jan.stola
 maintainer:     Ryan Scott <ryan.gl.scott@gmail.com>
 bug-reports:    https://github.com/goldfirere/singletons/issues
 stability:      experimental
-tested-with:    GHC == 9.12.2
+tested-with:    GHC == 9.14.1
 extra-doc-files:    CHANGES.md
 extra-source-files: README.md
                     tests/README.md
@@ -40,7 +40,7 @@ description:
     .
     @singletons-base@ uses code that relies on bleeding-edge GHC language
     extensions. As such, @singletons-base@ only supports the latest major version
-    of GHC (currently GHC 9.12). For more information,
+    of GHC (currently GHC 9.14). For more information,
     consult the @singletons@
     @<https://github.com/goldfirere/singletons/blob/master/README.md README>@.
     .
@@ -67,11 +67,11 @@ source-repository head
 
 library
   hs-source-dirs:     src
-  build-depends:      base             >= 4.21 && < 4.22,
+  build-depends:      base             >= 4.22 && < 4.23,
                       pretty,
                       singletons       == 3.0.*,
                       singletons-th    >= 3.5 && < 3.6,
-                      template-haskell >= 2.23 && < 2.24,
+                      template-haskell >= 2.24 && < 2.25,
                       text >= 1.2
   default-language:   GHC2024
   other-extensions:   TemplateHaskell
@@ -149,7 +149,7 @@ test-suite singletons-base-test-suite
   main-is:            SingletonsBaseTestSuite.hs
   other-modules:      SingletonsBaseTestSuiteUtils
 
-  build-depends:      base >= 4.21 && < 4.22,
+  build-depends:      base >= 4.22 && < 4.23,
                       bytestring >= 0.10.9,
                       deepseq >= 1.4.4,
                       filepath >= 1.3,

diff --git a/singletons-base/src/GHC/TypeLits/Singletons.hs b/singletons-base/src/GHC/TypeLits/Singletons.hs
@@ -21,9 +21,9 @@
 module GHC.TypeLits.Singletons (
   Natural, Symbol, Char,
   Sing,
-  SNat, pattern SNat,
-  SSymbol, pattern SSymbol, pattern SSym,
-  SChar, pattern SChar,
+  SNat, data SNat,
+  SSymbol, data SSymbol, data SSym,
+  SChar, data SChar,
   withKnownNat, withKnownSymbol, withKnownChar,
   Error, sError,
   ErrorWithoutStackTrace, sErrorWithoutStackTrace,

diff --git a/singletons-base/src/GHC/TypeLits/Singletons/Internal.hs b/singletons-base/src/GHC/TypeLits/Singletons/Internal.hs
@@ -24,9 +24,9 @@ module GHC.TypeLits.Singletons.Internal (
   Sing,
 
   Natural, TL.Symbol, Char,
-  TN.SNat, pattern TN.SNat,
-  TL.SSymbol, pattern TL.SSymbol, pattern SSym,
-  TL.SChar, pattern TL.SChar,
+  TN.SNat, data TN.SNat,
+  TL.SSymbol, data TL.SSymbol, data SSym,
+  TL.SChar, data TL.SChar,
   TN.withKnownNat, TL.withKnownSymbol, TL.withKnownChar,
   Error, sError,
   ErrorWithoutStackTrace, sErrorWithoutStackTrace,

diff --git a/singletons-base/tests/compile-and-dump/GradingClient/Database.golden b/singletons-base/tests/compile-and-dump/GradingClient/Database.golden
@@ -501,18 +501,18 @@ GradingClient/Database.hs:(0,0)-(0,0): Splicing declarations
       TFHelper_0123456789876543210 (VEC a_0123456789876543210 a_0123456789876543210) (VEC b_0123456789876543210 b_0123456789876543210) = Apply (Apply (&&@#@$) (Apply (Apply (==@#@$) a_0123456789876543210) b_0123456789876543210)) (Apply (Apply (==@#@$) a_0123456789876543210) b_0123456789876543210)
     instance PEq U where
       type (==) a a = TFHelper_0123456789876543210 a a
-    type ShowsPrec_0123456789876543210 :: GHC.Num.Natural.Natural
+    type ShowsPrec_0123456789876543210 :: GHC.Internal.Bignum.Natural.Natural
                                           -> U -> Symbol -> Symbol
-    type family ShowsPrec_0123456789876543210 (a :: GHC.Num.Natural.Natural) (a :: U) (a :: Symbol) :: Symbol where
+    type family ShowsPrec_0123456789876543210 (a :: GHC.Internal.Bignum.Natural.Natural) (a :: U) (a :: Symbol) :: Symbol where
       ShowsPrec_0123456789876543210 _ BOOL a_0123456789876543210 = Apply (Apply ShowStringSym0 "BOOL") a_0123456789876543210
       ShowsPrec_0123456789876543210 _ STRING a_0123456789876543210 = Apply (Apply ShowStringSym0 "STRING") a_0123456789876543210
       ShowsPrec_0123456789876543210 _ NAT a_0123456789876543210 = Apply (Apply ShowStringSym0 "NAT") a_0123456789876543210
       ShowsPrec_0123456789876543210 p_0123456789876543210 (VEC arg_0123456789876543210 arg_0123456789876543210) a_0123456789876543210 = Apply (Apply (Apply ShowParenSym0 (Apply (Apply (>@#@$) p_0123456789876543210) (FromInteger 10))) (Apply (Apply (.@#@$) (Apply ShowStringSym0 "VEC ")) (Apply (Apply (.@#@$) (Apply (Apply ShowsPrecSym0 (FromInteger 11)) arg_0123456789876543210)) (Apply (Apply (.@#@$) ShowSpaceSym0) (Apply (Apply ShowsPrecSym0 (FromInteger 11)) arg_0123456789876543210))))) a_0123456789876543210
     instance PShow U where
       type ShowsPrec a a a = ShowsPrec_0123456789876543210 a a a
-    type ShowsPrec_0123456789876543210 :: GHC.Num.Natural.Natural
+    type ShowsPrec_0123456789876543210 :: GHC.Internal.Bignum.Natural.Natural
                                           -> AChar -> Symbol -> Symbol
-    type family ShowsPrec_0123456789876543210 (a :: GHC.Num.Natural.Natural) (a :: AChar) (a :: Symbol) :: Symbol where
+    type family ShowsPrec_0123456789876543210 (a :: GHC.Internal.Bignum.Natural.Natural) (a :: AChar) (a :: Symbol) :: Symbol where
       ShowsPrec_0123456789876543210 _ CA a_0123456789876543210 = Apply (Apply ShowStringSym0 "CA") a_0123456789876543210
       ShowsPrec_0123456789876543210 _ CB a_0123456789876543210 = Apply (Apply ShowStringSym0 "CB") a_0123456789876543210
       ShowsPrec_0123456789876543210 _ CC a_0123456789876543210 = Apply (Apply ShowStringSym0 "CC") a_0123456789876543210

diff --git a/singletons-base/tests/compile-and-dump/Singletons/Classes.golden b/singletons-base/tests/compile-and-dump/Singletons/Classes.golden
@@ -16,20 +16,20 @@ Singletons/Classes.hs:(0,0)-(0,0): Splicing declarations
           data Foo = A | B
           data Foo2 = F | G
 
+          instance Eq Foo2 where
+            F == F = True
+            G == G = True
+            F == G = False
+            G == F = False
+          instance MyOrd Foo where
+            mycompare = fooCompare
           instance MyOrd () where
             mycompare _ = const EQ
           instance MyOrd Nat where
             Zero `mycompare` Zero = EQ
             Zero `mycompare` (Succ _) = LT
             (Succ _) `mycompare` Zero = GT
-            (Succ n) `mycompare` (Succ m) = m `mycompare` n
-          instance MyOrd Foo where
-            mycompare = fooCompare
-          instance Eq Foo2 where
-            F == F = True
-            G == G = True
-            F == G = False
-            G == F = False |]
+            (Succ n) `mycompare` (Succ m) = m `mycompare` n |]
   ======>
     const :: a -> b -> a
     const x _ = x