13 Pull requests merged by 6 people

• Explicitly check case‐sensitivity of file system for tests

  #19540 merged Jul 31, 2025

• Update changelog for 1.17.1

  #19550 merged Jul 31, 2025

• Update test requirements

  #19539 merged Jul 30, 2025

• [mypyc] Enable free threading when compiling multiple modules

  #19541 merged Jul 30, 2025

• [mypyc] Make type objects immortal if using free threading

  #19538 merged Jul 30, 2025

• Use cache for DictExpr as well

  #19536 merged Jul 30, 2025

• Use cache for OpExpr

  #19523 merged Jul 29, 2025

• perf: deduplicate fast_container_type and fast_dict_type items before joining

  #19409 merged Jul 29, 2025

• Move self argument checks to a later phase - after decorator application, if any

  #19490 merged Jul 28, 2025

• Try simple-minded call expression cache

  #19505 merged Jul 28, 2025

• [mypyc] Fix list.pop primitive on free-threaded builds

  #19522 merged Jul 28, 2025

• [mypyc] Only generate an export table if using separate compilation

  #19521 merged Jul 28, 2025

• Various minor docstring and comment updates

  #19519 merged Jul 28, 2025

7 Pull requests opened by 5 people

• Update crash issue template to use syntax highlighting in code blocks

  #19527 opened Jul 28, 2025

• [mypyc] Add prefix to attributes of generator classes

  #19535 opened Jul 29, 2025

• [wip] [mypyc] feat: quasi-constant folding for DictExpr and TupleExpr

  #19542 opened Jul 30, 2025

• Keep trivial instances and aliases during expansion

  #19543 opened Jul 30, 2025

• Move Windows tests from oldest to newest version

  #19545 opened Jul 30, 2025

• Update update_data.py: make the space in error comments optional

  #19546 opened Jul 30, 2025

• Document mypy exit codes

  #19549 opened Jul 31, 2025

10 Issues closed by 2 people

• [docs] Update Code Conventions to reflect the switch from flake8 to ruff

  #19498 closed Jul 31, 2025

• Wildly inconsistent performance for seemingly trivial changes to source code

  #14271 closed Jul 30, 2025

• Mypy errors out for deeply nested dictionaries

  #14636 closed Jul 30, 2025

• Mypy hangs indefinitely trying to analyse a file with huge nested dicts

  #14970 closed Jul 30, 2025

• Pathological performance on big list and dict literals

  #8247 closed Jul 30, 2025

• Mypy stuck with polynomial using NumPy

  #14978 closed Jul 29, 2025

• :bug: Methods converted to `staticmethod`s using a decorator not treated as `staticmethod`s

  #13434 closed Jul 28, 2025

• False positive "Method must have at least one argument" with `@enum.member`

  #18720 closed Jul 28, 2025

• Erroneous "Self argument missing" error when decorators are used

  #19392 closed Jul 28, 2025

• Mypy doesn't recognize `@staticmethod`-like decorator

  #18989 closed Jul 28, 2025

15 Issues opened by 13 people

• join is not always permutation invariant

  #19551 opened Jul 31, 2025

• Config errors sometimes result in exit code 0

  #19548 opened Jul 31, 2025

• "# E:" lines (etc) in test files are ignored at the beginning of lines

  #19547 opened Jul 31, 2025

• `[mypyc]` indexing fixed-length tuples is extremely slow and gets slower with increse in length

  #19537 opened Jul 30, 2025

• Literal list ternary behave unexpected

  #19534 opened Jul 29, 2025

• TypeVarTuple instantiation with the empty tuple in Generic not being recognized as such

  #19533 opened Jul 29, 2025

• Type narrowing of indexing a StrEnum created in a function

  #19532 opened Jul 29, 2025

• ImportError: dynamic module does not define module export function

  #19531 opened Jul 29, 2025

• Type narrowing of `TypeVar` with abstract bases classes causes `|return-value]` error

  #19530 opened Jul 29, 2025

• Type narrowing for through `not issubclass(…)` broken for union of TypeVar instance / types in 1.17

  #19529 opened Jul 29, 2025

• No type narrowing when `isinstance` list comprehension is assigned to the same variable

  #19528 opened Jul 29, 2025

• Crash when type variable has same name as an external symbol with an erroneous definition in PEP 695 generic class

  #19526 opened Jul 28, 2025

• Incorrect handling of overloads with `defaultdict` and `MutableMapping`

  #19525 opened Jul 28, 2025

• Multiple extensions using `get_base_class_hook` interfere with each other

  #19524 opened Jul 28, 2025

• Classmethods as attrs converters

  #19520 opened Jul 28, 2025

23 Unresolved conversations

Sometimes conversations happen on old items that aren’t yet closed. Here is a list of all the Issues and Pull Requests with unresolved conversations.

• Fix #19491, crash when using enable_error_code value of wrong type in pyproject.toml

  #19494 commented on Jul 31, 2025 • 3 new comments

• feat: new mypyc primitive for weakref.ref

  #19099 commented on Jul 31, 2025 • 1 new comment

• [wip] [mypyc] feat: unroll certain for loops with known params

  #19518 commented on Jul 30, 2025 • 0 new comments

• [match-case] Fix narrowing of class pattern with union-argument.

  #19517 commented on Jul 28, 2025 • 0 new comments

• Enable pretty by default

  #19510 commented on Jul 30, 2025 • 0 new comments

• [mypyc] feat: cache len for iterating over immutable types

  #19503 commented on Jul 30, 2025 • 0 new comments

• [mypyc] feat: unwrap NewType types to their base types for optimized code paths

  #19497 commented on Jul 30, 2025 • 0 new comments

• [match-case] fix matching against `typing.Callable` and `Protocol` types.

  #19471 commented on Jul 28, 2025 • 0 new comments

• [PEP 695] Fix incorrect Variance Computation with Polymorphic Methods.

  #19466 commented on Jul 28, 2025 • 0 new comments

• [PEP 696] Fix swapping TypeVars with defaults.

  #19449 commented on Jul 28, 2025 • 0 new comments

• Do not display import-related errors after module-level always false assert

  #19347 commented on Jul 30, 2025 • 0 new comments

• Check slots assignments on self types

  #19332 commented on Jul 30, 2025 • 0 new comments

• Fix/attrs init overload

  #19104 commented on Jul 31, 2025 • 0 new comments

• Split import-untyped into import-untyped and import-untyped-stubs-available

  #19101 commented on Jul 29, 2025 • 0 new comments

• Improve cli help somewhat

  #19073 commented on Jul 31, 2025 • 0 new comments

• Add a flag `--enable-all-error-codes`, which enables all error codes

  #19048 commented on Jul 31, 2025 • 0 new comments

• Consider property access from class objects (now for real)

  #18969 commented on Jul 29, 2025 • 0 new comments

• Disallow literal `0` step in slice expressions

  #18065 commented on Jul 29, 2025 • 0 new comments

• 1.17 Release Planning

  #19306 commented on Jul 31, 2025 • 0 new comments

• EncodingWarning when running under PyPy

  #17057 commented on Jul 31, 2025 • 0 new comments

• Include binary wheels for ARM Windows

  #18593 commented on Jul 30, 2025 • 0 new comments

• Allow ignore to be on any line of multi-line statement

  #12341 commented on Jul 30, 2025 • 0 new comments

• Allow mypy to flag `str` matching against `Sequence[str]` as an error

  #11001 commented on Jul 29, 2025 • 0 new comments