Issues

• False negative involving overload and walrus

  bugtopic-overloadstopic-type-narrowing
  python/mypy#22264 · Filter by author hauntsaninja opened on Oct 21, 2026

• Assignment expression in a call argument changes the types of earlier arguments

  bugtopic-pep-572topic-runtime-semanticstopic-type-narrowing
  python/mypy#22138 · Filter by author rheard opened on Oct 7, 2026

• isinstance with a tuple of types narrows unsoundly, causing TypeError in mypyc-compiled code

  affects-mypycbugtopic-type-narrowing
  python/mypy#22122 · Filter by author VaggelisD opened on Oct 6, 2026
  1

• Incorrect narrowing of Enum.Flag

  bugtopic-enumtopic-type-narrowing
  python/mypy#21937 · Filter by author zedzhen opened on Sep 4, 2026
  2

• [2.0 regression] Bad result from heuristic non-narrowing of type[T]

  bugtopic-type-narrowing
  python/mypy#21701 · Filter by author neutrinoceros opened on Jul 8, 2026
  1

• Missing TypeIs narrowing with covariant generic

  bugtopic-type-narrowingtopic-typeguard-typeis
  python/mypy#21641 · Filter by author JelleZijlstra opened on Jun 24, 2026

• != (None, None) Narrowing only in else branch

  featuretopic-type-narrowing
  python/mypy#21598 · Filter by author InvincibleRMC opened on Jun 7, 2026
  2

• Incorrect type narrowing when swapping variables after isinstance check

  bugtopic-type-narrowing
  python/mypy#21586 · Filter by author p-sawicki opened on Jun 3, 2026

• Get rid of the "flipping behaviour" in narrowign by equality/identity

  needs discussiontopic-type-narrowing
  python/mypy#21365 · Filter by author ilevkivskyi opened on Apr 29, 2026
  3

• not isinstance(x, cls) inside classmethod does not narrow type

  bugtopic-self-typestopic-type-narrowing
  python/mypy#21271 · Filter by author robsdedude opened on Apr 20, 2026

• Interaction between an enum alias and assert_never() seems to fail

  bugtopic-enumtopic-type-narrowing
  python/mypy#21117 · Filter by author jhbuhrman opened on Mar 31, 2026
  3

• Type-narrowing of a list item for an inline list multiplied with a type-guard on said item

  featuretopic-type-narrowing
  python/mypy#21099 · Filter by author Avasam opened on Mar 24, 2026

• TypeForm does not overlap with classes that represent special forms at runtime.

  bugtopic-reachabilitytopic-type-formtopic-type-narrowing
  python/mypy#21048 · Filter by author danielknell opened on Mar 19, 2026
  2

• Unsound typing using isinstance

  bugpriority-0-hightopic-type-narrowing
  python/mypy#20969 · Filter by author zacharie-moughanim opened on Mar 4, 2026
  3

• mypy is unable to narrow a union type that includes a StrEnum subclass and a Literal

  bugtopic-enumtopic-type-narrowing
  python/mypy#20915 · Filter by author exg opened on Feb 27, 2026

• Inconsistent feeling handling of Any in binder

  bugtopic-type-narrowing
  python/mypy#20870 · Filter by author hauntsaninja opened on Feb 23, 2026
  2

• Incorrect narrowing between two different unions

  bugtopic-type-narrowing
  python/mypy#20820 · Filter by author A5rocks opened on Feb 15, 2026
  2

• Support type narrowing on __eq__ with TypeGuard/TypeIs

  featuretopic-type-narrowingtopic-typeguard-typeis
  python/mypy#20779 · Filter by author frankie567 opened on Feb 11, 2026
  1

• callable() fails to narrow type to Callable

  featuretopic-type-narrowing
  python/mypy#20748 · Filter by author cjwatson opened on Feb 5, 2026
  4

• Regression: Type of instance variable narrowed incorrectly after is not expression

  bugtopic-type-narrowing
  python/mypy#20736 · Filter by author p-sawicki opened on Feb 4, 2026
  2

• Type narrowing of target: type[T] using insinstance seems to fool mypy

  bugtopic-type-narrowing
  python/mypy#20690 · Filter by author juliancoffee opened on Jan 29, 2026
  3

• Regression with narrowing with negative intersection

  bugtopic-type-narrowing
  python/mypy#20597 · Filter by author hauntsaninja opened on Jan 16, 2026
  1

• not isinstance(float_arg, float) should narrow to int; not isinstance(complex_arg, complex) should narrow to float

  bugtopic-runtime-semanticstopic-type-narrowing
  python/mypy#20484 · Filter by author kmaglione opened on Dec 29, 2025

• [1.19 regression] Incorrect return type inference on enum methods

  bugtopic-enumtopic-inferencetopic-type-narrowing
  python/mypy#20434 · Filter by author mmiller-max opened on Dec 17, 2025
  6

• Final (context-sensitive Literal) doesn't support type narrowing

  bugtopic-finaltopic-literal-typestopic-type-narrowing
  python/mypy#19814 · Filter by author Dreamsorcerer opened on Sep 9, 2025