René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"Annotation scopes containing nested scopes","articleBody":"# Bug report\n\n### Bug description:\n\nThe following code causes a SystemError during compilation.\n\n```python\n\nclass name_2[*name_5, name_3: int]:\n    (name_3 := name_4)\n\n    class name_4[name_5: name_5]((name_4 for name_5 in name_0 if name_3), name_2 if name_3 else name_0):\n        pass\n```\n\noutput (Python 3.12.0rc2+):\n```python\nSystemError: compiler_lookup_arg(name='name_3') with reftype=3 failed in \u003cgeneric parameters of name_4\u003e; freevars of code \u003cgenexpr\u003e: ('name_3',)\n```\n\nremoving the named-expression makes it worse and causes a crash\n\n```python\n\nclass name_2[*name_5, name_3: int]:\n\n    class name_4[name_5: name_5]((name_4 for name_5 in name_0 if name_3), name_2 if name_3 else name_0):\n        pass\n```\n\noutput (Python 3.12.0rc2+):\n```python\nTraceback (most recent call last):\n  File \"/home/frank/projects/pysource-codegen/bug2.py\", line 2, in \u003cmodule\u003e\n    class name_2[*name_5, name_3: int]:\n  File \"/home/frank/projects/pysource-codegen/bug2.py\", line 2, in \u003cgeneric parameters of name_2\u003e\n    class name_2[*name_5, name_3: int]:\n  File \"/home/frank/projects/pysource-codegen/bug2.py\", line 4, in name_2\n    class name_4[name_5: name_5]((name_4 for name_5 in name_0 if name_3), name_2 if name_3 else name_0):\n  File \"/home/frank/projects/pysource-codegen/bug2.py\", line 4, in \u003cgeneric parameters of name_4\u003e\n    class name_4[name_5: name_5]((name_4 for name_5 in name_0 if name_3), name_2 if name_3 else name_0):\n                                                       ^^^^^^\nNameError: name 'name_0' is not defined\nModules/gcmodule.c:113: gc_decref: Assertion \"gc_get_refs(g) \u003e 0\" failed: refcount is too small\nEnable tracemalloc to get the memory block allocation traceback\n\nobject address  : 0x7f4c77059a30\nobject refcount : 1\nobject type     : 0x560ea4b6cfe0\nobject type name: dict\nobject repr     : {'__module__': '__main__', '__qualname__': 'name_2', '__type_params__': (name_5, name_3)}\n\nFatal Python error: _PyObject_AssertFailed: _PyObject_AssertFailed\nPython runtime state: finalizing (tstate=0x0000560ea4cc9ba0)\n\nCurrent thread 0x00007f4c7756c280 (most recent call first):\n  Garbage-collecting\n  \u003cno Python frame\u003e\n```\n\nside note:\nThe reason for the strange looking language constructs and variable names is that I generated this code. I found it while working on my pysource-codegen library.\n\n### CPython versions tested on:\n\n3.12\n\n### Operating systems tested on:\n\nLinux\n\n\u003c!-- gh-linked-prs --\u003e\n### Linked PRs\n* gh-109123\n* gh-109173\n* gh-109196\n* gh-109297\n* gh-118019\n* gh-118160\n\u003c!-- /gh-linked-prs --\u003e\n","author":{"url":"https://github.com/15r10nk","@type":"Person","name":"15r10nk"},"datePublished":"2023-09-07T22:35:51.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":13},"url":"https://github.com/109118/cpython/issues/109118"}