Run flake8-bugbear in CI

.github/workflows/check.yml

@@ -32,6 +32,7 @@ jobs:
         python-version: "3.10"
     # flake8 not in requirements-dev.txt, because versions specified in setup.py are complicated
     - run: pip install -e .
+    - run: pip install -r requirements-dev.txt
     - run: |
         flake8 $(git ls-files | grep 'py$')
   tests:

pyi.py

@@ -362,8 +362,8 @@ def active(self) -> bool:
 
 
 class PyiVisitor(ast.NodeVisitor):
-    def __init__(self, filename: Path = Path("none")) -> None:
-        self.filename = filename
+    def __init__(self, filename: Path | None = None) -> None:
+        self.filename = Path("(none)") if filename is None else filename
         self.errors: list[Error] = []
         # Mapping of all private TypeVars/ParamSpecs/TypeVarTuples to the nodes where they're defined
         self.typevarlike_defs: dict[TypeVarInfo, ast.Assign] = {}

requirements-dev.txt

@@ -2,3 +2,4 @@ black==22.1.0
 pytest==6.2.5
 mypy==0.931
 isort==5.10.1
+flake8-bugbear==22.1.11