diff --git a/.github/workflows/haskell-ci.yml b/.github/workflows/haskell-ci.yml
index 738d201..1fdaa76 100644
--- a/.github/workflows/haskell-ci.yml
+++ b/.github/workflows/haskell-ci.yml
@@ -11,6 +11,12 @@ on:
       - 'master'
   schedule:
     - cron: 0 0 * * *
+  workflow_dispatch:
+    inputs:
+      nightly:
+        description: Run with the same settings as a nightly build
+        type: boolean
+        default: false
 
 concurrency:
   group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.ref }}
@@ -29,6 +35,14 @@ jobs:
     runs-on: ${{ matrix.os }}
 
     steps:
+      - name: Set NIGHTLY environment variable if the job was triggered by the scheduler
+        if: "${{ github.event_name == 'schedule'
+              || contains(github.event.pull_request.title, 'nightly')
+              || contains(github.event.pull_request.title, 'NIGHTLY')
+              || github.event_name == 'workflow_dispatch' && github.event.inputs.nightly }}"
+        run: |
+          echo "NIGHTLY=true" >> $GITHUB_ENV
+
       - uses: actions/checkout@v4
       - uses: haskell-actions/setup@v2
         with:
@@ -50,40 +64,48 @@ jobs:
     name: Stack
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v4
+      - name: Set NIGHTLY environment variable if the job was triggered by the scheduler
+        if: "${{ github.event_name == 'schedule'
+              || contains(github.event.pull_request.title, 'nightly')
+              || contains(github.event.pull_request.title, 'NIGHTLY')
+              || github.event_name == 'workflow_dispatch' && github.event.inputs.nightly }}"
+        run: |
+          echo "NIGHTLY=true" >> $GITHUB_ENV
+
+      - uses: actions/checkout@v4
 
-    - uses: haskell-actions/setup@v2
-      id: setup-haskell-stack
-      name: Setup Haskell
-      with:
-        enable-stack: true
-        stack-version: latest
-        ghc-version: 9.6.7
+      - uses: haskell-actions/setup@v2
+        id: setup-haskell-stack
+        name: Setup Haskell
+        with:
+          enable-stack: true
+          stack-version: latest
+          ghc-version: 9.6.7
 
-    - name: Cache
-      id: cache
-      uses: actions/cache@v4
-      with:
-        path: |
-          ${{ steps.setup-haskell-stack.outputs.stack-root }}
-          .stack-work
-        key: ${{ runner.os }}-stack-${{ github.sha }}
-        restore-keys: ${{ runner.os }}-stack
+      - name: Cache
+        id: cache
+        uses: actions/cache@v4
+        with:
+          path: |
+            ${{ steps.setup-haskell-stack.outputs.stack-root }}
+            .stack-work
+          key: ${{ runner.os }}-stack-${{ github.sha }}
+          restore-keys: ${{ runner.os }}-stack
 
-    - name: Test
-      run: stack test --coverage --flag constrained-generators:dev
+      - name: Test
+        run: stack test --coverage --flag constrained-generators:dev
 
-    - uses: actions/cache/save@v4
-      with:
-        path: |
-          ${{ steps.setup-haskell-stack.outputs.stack-root }}
-          .stack-work
-        key: ${{ runner.os }}-stack-${{ github.sha }}
+      - uses: actions/cache/save@v4
+        with:
+          path: |
+            ${{ steps.setup-haskell-stack.outputs.stack-root }}
+            .stack-work
+          key: ${{ runner.os }}-stack-${{ github.sha }}
 
-    - name: Upload coverage report
-      env:
-        COVERALLS_REPO_TOKEN: ${{ secrets.COVERALLS_REPO_TOKEN }}
-      run: |
-        [ -n "${COVERALLS_REPO_TOKEN}" ]
-        curl -L https://github.com/rubik/stack-hpc-coveralls/releases/download/v0.0.7.0/shc-Linux-X64.tar.bz2 | tar xj shc
-        ./shc --repo-token="$COVERALLS_REPO_TOKEN" --partial-coverage --fetch-coverage combined all
+      - name: Upload coverage report
+        env:
+          COVERALLS_REPO_TOKEN: ${{ secrets.COVERALLS_REPO_TOKEN }}
+        run: |
+          [ -n "${COVERALLS_REPO_TOKEN}" ]
+          curl -L https://github.com/rubik/stack-hpc-coveralls/releases/download/v0.0.7.0/shc-Linux-X64.tar.bz2 | tar xj shc
+          ./shc --repo-token="$COVERALLS_REPO_TOKEN" --partial-coverage --fetch-coverage combined all