[phalberg]

Summary

Adding some type hints for bugbear.py!

Issue

Part of #478.

Desc

While running mypy on bugbear.py (not strict, we will get to that one hopefully 🚀) I got the following errors:

bugbear.py:112: error: Argument 1 to "extend" of "list" has incompatible type "Iterator[AST]"; expected "Iterable[stmt]"  [arg-type]
bugbear.py:179: error: Argument 1 to "_only_comment_after" of "BugBearChecker" has incompatible type "Expr"; expected "expr"  [arg-type]
bugbear.py:1825: error: Argument 1 to "append" of "list" has incompatible type "FunctionDef"; expected "Lambda"  [arg-type]
bugbear.py:2780: error: "expr" has no attribute "id"  [attr-defined]
bugbear.py:3176: error: Need type annotation for "outer_names" (hint: "outer_names: set[<type>] = ...")  [var-annotated]
bugbear.py:3220: error: Incompatible types in assignment (expression has type "expr | None", variable has type "expr")  [assignment]
Found 6 errors in 1 file (checked 1 source file)

It seems happy after this change:

Success: no issues found in 1 source file

Note: Please do double check if all of these types make sense though, I must admit that i have not checked thoroughly neither am i completely used to the codebase yet...

[phalberg]

This seems somewhat useless to check, since we have L2776-L2777 but I am not sure if there are simpler ways to satisfy mypy -- open for suggestions :)

[Copilot]

Copilot was unable to review this pull request because the user who requested the review has insufficient remaining quota.

[Copilot]

Copilot was unable to review this pull request because the user who requested the review has insufficient remaining quota.

[cooperlees]

AI review on behalf of @cooperlees — I checked out the PR branch, verified each hunk, ran mypy and the test suite.

Verdict: Approve — all 6 changes are behavior-preserving typing fixes:

1. stack: list[ast.AST] + extend() — same as list(body), fixes Iterator[AST] vs Iterable[stmt] error. Good.
2. _only_comment_after(node.value) instead of (node) — matches the ast.expr signature. Expr and its Constant value share the same span so observable behavior is identical. Correct fix.
3. safe_functions: list[AsyncFunctionDef | Lambda | FunctionDef] — pure annotation matching FUNCTION_NODES. Good.
4. B913 isinstance(target, ast.Name) guard — redundant given the early-return above it, but harmless and satisfies expr has no attribute id. No behavior change. Good.
5. outer_names: set[str] — pure annotation. Good.
6. B046 kw_value is None: return — previously value=None would just fall through the isinstance checks with no error; early return is equivalent and narrows expr | None to expr. Correct and clearer.

Verification: mypy bugbear.py is clean (only unrelated missing flake8.exceptions stubs), pytest tests/ -q passes (142 passed, 2 skipped).

Note: This review was written by AI on behalf of cooperlees.