break CI into three stages: build, test, and haddock.

.github/workflows/ci.yaml

@@ -1,3 +1,7 @@
+name: Haskell CI
+on:
+  - push
+
 jobs:
   build:
     runs-on: ubuntu-latest
@@ -26,6 +30,10 @@ jobs:
         run: cabal build all --enable-tests --enable-benchmarks --only-dependencies
       - name: build all
         run: cabal build all --enable-tests --enable-benchmarks
+      - uses: "actions/cache@v2"
+        with:
+          key: "${{ runner.os }}-${{ matrix.ghc }}-build-cabal-${{ hashFiles('cabal.project.freeze') }}"
+          path: "${{ steps.setup-haskell-cabal.outputs.cabal-store }} dist-newstyle"
       - name: test all
         run: cabal test test-hslice --enable-tests
       - name: haddock all
@@ -39,6 +47,81 @@ jobs:
           - '9.2.8'
           - '9.0.2'
           - '8.10.7'
-name: Haskell CI
-on:
-  - push
+  test:
+    needs: build
+    runs-on: ubuntu-latest
+    steps:
+      - uses: "actions/checkout@v3"
+      - id: setup-haskell-cabal
+        uses: "haskell-actions/setup@v2"
+        with:
+          cabal-version: "${{ matrix.cabal }}"
+          enable-stack: false
+          ghc-version: "${{ matrix.ghc }}"
+      - name: Update Hackage repository
+        run: cabal update
+      - name: cabal.project.local.ci
+        run: |
+          if [ -e cabal.project.local.ci ]; then
+            cp cabal.project.local.ci cabal.project.local
+          fi
+      - name: freeze
+        run: cabal freeze
+      - name: Install dependencies
+        run: cabal build all --enable-tests --enable-benchmarks --only-dependencies
+      - name: build all
+        run: cabal build all --enable-tests --enable-benchmarks
+      - uses: "actions/cache@v2"
+        with:
+          key: "${{ runner.os }}-${{ matrix.ghc }}-build-cabal-${{ hashFiles('cabal.project.freeze') }}"
+          path: "${{ steps.setup-haskell-cabal.outputs.cabal-store }} dist-newstyle"
+      - name: test all
+        run: cabal test test-hslice --enable-tests
+    strategy:
+      matrix:
+        cabal:
+          - '3.10'
+        ghc:
+          - '9.4.6'  
+          - '9.2.8'
+          - '9.0.2'
+          - '8.10.7'
+  haddock:
+    needs: build
+    runs-on: ubuntu-latest
+    steps:
+      - uses: "actions/checkout@v3"
+      - id: setup-haskell-cabal
+        uses: "haskell-actions/setup@v2"
+        with:
+          cabal-version: "${{ matrix.cabal }}"
+          enable-stack: false
+          ghc-version: "${{ matrix.ghc }}"
+      - name: Update Hackage repository
+        run: cabal update
+      - name: cabal.project.local.ci
+        run: |
+          if [ -e cabal.project.local.ci ]; then
+            cp cabal.project.local.ci cabal.project.local
+          fi
+      - name: freeze
+        run: cabal freeze
+      - name: Install dependencies
+        run: cabal build all --enable-tests --enable-benchmarks --only-dependencies
+      - name: build all
+        run: cabal build all --enable-tests --enable-benchmarks
+      - uses: "actions/cache@v2"
+        with:
+          key: "${{ runner.os }}-${{ matrix.ghc }}-build-cabal-${{ hashFiles('cabal.project.freeze') }}"
+          path: "${{ steps.setup-haskell-cabal.outputs.cabal-store }} dist-newstyle"
+      - name: haddock all
+        run: cabal haddock all 
+    strategy:
+      matrix:
+        cabal:
+          - '3.10'
+        ghc:
+          - '9.4.6'  
+          - '9.2.8'
+          - '9.0.2'
+          - '8.10.7'