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{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"The `cases_generator` handles some instructions incorrectly","articleBody":"I triggered this `assert`...\r\n\r\n```py\r\nTraceback (most recent call last):\r\n  File \"/home/brandtbucher/cpython/./Tools/cases_generator/generate_cases.py\", line 1609, in \u003cmodule\u003e\r\n    main()\r\n  File \"/home/brandtbucher/cpython/./Tools/cases_generator/generate_cases.py\", line 1604, in main\r\n    a.write_metadata()\r\n  File \"/home/brandtbucher/cpython/./Tools/cases_generator/generate_cases.py\", line 1260, in write_metadata\r\n    assert not instr.active_caches, (instr.name, instr.cache_effects)\r\nAssertionError: ('TO_BOOL_ALWAYS_TRUE', [CacheEffect(context=\u003cPython/bytecodes.c: 1807-1810\u003e, name='unused', size=1), CacheEffect(context=\u003cPython/bytecodes.c: 1811-1814\u003e, name='version', size=2)]\r\n```\r\n\r\n...while defining this new instruction...\r\n\r\n```c\r\n        inst(TO_BOOL_ALWAYS_TRUE, (unused/1, version/2, value -- res)) {\r\n            // This one is a bit weird, because we expect *some* failures:\r\n            assert(version);\r\n            DEOPT_IF(Py_TYPE(value)-\u003etp_version_tag != version, TO_BOOL);\r\n            STAT_INC(TO_BOOL, hit);\r\n            DECREF_INPUTS();\r\n            res = Py_True;\r\n        }\r\n```\r\n\r\n@gvanrossum thinks that the `assert` is incorrect: it appears that the current code doesn't know how to handle an instruction that uses caches but *doesn't* have an oparg.\n\n\u003c!-- gh-linked-prs --\u003e\n### Linked PRs\n* gh-106252\n\u003c!-- /gh-linked-prs --\u003e\n","author":{"url":"https://github.com/brandtbucher","@type":"Person","name":"brandtbucher"},"datePublished":"2023-06-29T18:24:09.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":0},"url":"https://github.com/106250/cpython/issues/106250"}