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Remove unnecessary error message for match class patterns#19708

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hauntsaninja merged 1 commit intopython:masterfromcdce8p:match-class-pattern-error

Aug 23, 2025

Merged

Remove unnecessary error message for match class patterns#19708

hauntsaninja merged 1 commit intopython:masterfromcdce8p:match-class-pattern-error

Aug 23, 2025

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cdce8p commentedAug 21, 2025

RemoveCannot determine type of ... error for class patterns if the class to match cannot be resolved. In these cases aName ... is not defined error is already emitted. The captured variable should simply be inferred asAny.

Previously, this was especially an issue for class matches to a class from an untyped library together with a MemberExpr. An example from pylint / astroid which shouldn't emit any errors:

fromtypingimportAnyfromastroidimportnodesdeffunc(var:Any)->None:matchvar:casenodes.Assign(targets=t):reveal_type(t)# Any

cdce8p added the topic-match-statementPython 3.10's match statement label

Aug 21, 2025

Remove unnecessary error message for match class patterns

a9aa418

cdce8p force-pushed thematch-class-pattern-error branch from1026b0e toa9aa418Compare

August 21, 2025 18:34

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github-actionsbot commentedAug 21, 2025

Diff frommypy_primer, showing the effect of this PR on open source code:

core (https://github.com/home-assistant/core)- homeassistant/components/onkyo/media_player.py:354: error: Cannot determine type of "volume"  [has-type]- homeassistant/components/onkyo/media_player.py:360: error: Cannot determine type of "muting"  [has-type]- homeassistant/components/onkyo/media_player.py:363: error: Cannot determine type of "source"  [has-type]- homeassistant/components/onkyo/media_player.py:364: error: Cannot determine type of "source"  [has-type]- homeassistant/components/onkyo/media_player.py:366: error: Cannot determine type of "source"  [has-type]- homeassistant/components/onkyo/media_player.py:383: error: Cannot determine type of "sound_mode"  [has-type]- homeassistant/components/onkyo/media_player.py:384: error: Cannot determine type of "sound_mode"  [has-type]- homeassistant/components/onkyo/media_player.py:386: error: Cannot determine type of "sound_mode"  [has-type]- homeassistant/components/onkyo/media_player.py:398: error: Cannot determine type of "hdmi_output"  [has-type]- homeassistant/components/onkyo/media_player.py:403: error: Cannot determine type of "preset"  [has-type]