Add CI job for mypy

.github/workflows/mypy.yml

@@ -0,0 +1,40 @@
+name: Mathics3 (Type checking)
+
+on:
+  push:
+    branches: [ master ]
+  pull_request:
+    branches: [ master ]
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        python-version: ['3.12']
+    steps:
+    - uses: actions/checkout@v4
+    - name: Set up Python ${{ matrix.python-version }}
+      uses: actions/setup-python@v5
+      with:
+        python-version: ${{ matrix.python-version }}
+    - name: Install dependencies
+      run: |
+        sudo apt update -qq && sudo apt install llvm-dev remake
+        python -m pip install --upgrade pip
+        # We can comment out after next Mathics-Scanner release
+        # python -m pip install -e git+https://github.com/Mathics3/mathics-scanner#egg=Mathics-Scanner[full]
+        git clone https://github.com/Mathics3/mathics-scanner.git
+        cd mathics-scanner/
+        pip install -e .
+        cd ..
+
+    - name: Install Mathics with minimum dependencies
+      run: |
+        make develop
+    - name: Run mypy
+      run: |
+        pip install mypy==1.13 sympy==1.12
+        touch ./mathics-scanner/mathics_scanner/py.typed
+        pip install ./mathics-scanner/
+        mypy --install-types --non-interactive mathics

pyproject.toml

@@ -118,5 +118,9 @@ version = {attr = "mathics.version.__version__"}
 force_union_syntax = true
 
 [[tool.mypy.overrides]]
-module = ["mpmath", "llvmlite.*"]
+module = ["mpmath", "llvmlite.*", "trepan.*"]
 ignore_missing_imports = true
+
+[[tool.mypy.overrides]]
+module = ["mathics.benchmark", "mathics.builtin.*", "mathics.eval.*", "test.*"]
+ignore_errors = true