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{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"Python 3.14.1+ annotationlib regression: ForwardRef.__hash__ raises `TypeError: unhashable type: 'cell'`","articleBody":"# Bug report\n\n### Bug description:\n\n\n\nThis issue was originally reported in the [beartype](https://github.com/beartype/beartype) library (Ref: https://github.com/beartype/beartype/issues/610), but investigation suggests it may stem from a change in Python’s `annotationlib.ForwardRef` implementation.\n\nStarting with Python 3.14.1, deferred annotations (PEP 649) involving self-referential return type is raising: `TypeError: unhashable type: 'cell'` at decoration time. **This worked correctly in Python 3.14.0** and the issue appears to persist in 3.14.2, suggesting a regression. \n\nThe error originates from `annotationlib.ForwardRef.__hash__`, which attempts to hash internal state containing non-hashable cell objects. Although observed via beartype, this may affects any downstream library that hashes ForwardRef objects. The following code seems to be raising the issue: \n**`tuple(sorted(self.__cell__.items())) if isinstance(self.__cell__, dict) else self.__cell__,`**\nhttps://github.com/python/cpython/blob/1857a40807daeae3a1bf5efb682de9c9ae6df845/Lib/annotationlib.py#L290-L299\n\n----\n\n#### Code:\n```python\n#!pip install beartype==0.22.9\n\nfrom beartype import beartype\n\nclass MyClass:\n    @beartype\n    def foo(self) -\u003e MyClass:\n        return MyClass()\n\nprint(MyClass().foo())\n\n```\n#### Observed behavior:\nThe program fails during decoration with the error: `TypeError: unhashable type: 'cell'`\n\n```bash\nFile \".../beartype/_check/metadata/hint/hintsane.py\", line 242, in __init__\n    self._hash = hash((hint, hint_recursable_to_depth, typearg_to_hint))\nFile \".../python3.14/annotationlib.py\", line 291, in __hash__\n    return hash((..., tuple(sorted(self.__extra_names__.items()))))\nTypeError: unhashable type: 'cell'\n\n```\n\nInspection shows:\n```python\n\u003e\u003e\u003e self.__cell__\n{'__classdict__': \u003ccell at 0x...: dict object\u003e}\n\u003e\u003e\u003e tuple(sorted(self.__cell__.items()))\n(('__classdict__', \u003ccell at 0x...\u003e),)\n\n```\nSince cell objects are not hashable, this causes __hash__ to fail.\n\n\n### Affected Versions:\nPython `3.14.1` and `3.14.2`\nOS Tested on: MacOS\n\n\n\n\n\n\n### CPython versions tested on:\n\n3.14\n\n### Operating systems tested on:\n\nmacOS\n\n\u003c!-- gh-linked-prs --\u003e\n### Linked PRs\n* gh-143848\n* gh-144020\n\u003c!-- /gh-linked-prs --\u003e\n","author":{"url":"https://github.com/abhinand-c","@type":"Person","name":"abhinand-c"},"datePublished":"2026-01-14T10:31:02.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":4},"url":"https://github.com/143831/cpython/issues/143831"}