René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"Crash in TypeVarType.serialize() when extracting dict().get as a variable","articleBody":"Repro:\r\n```python\r\nfrom typing import *\r\nd = {}  # type: Dict[str, int]\r\ng = d.get\r\n```\r\nTraceback:\r\n```\r\nTraceback (most recent call last):\r\n  File \"/usr/local/lib/python3.6/runpy.py\", line 193, in _run_module_as_main\r\n    \"__main__\", mod_spec)\r\n  File \"/usr/local/lib/python3.6/runpy.py\", line 85, in _run_code\r\n    exec(code, run_globals)\r\n  File \"/Users/guido/src/mypy/mypy/__main__.py\", line 5, in \u003cmodule\u003e\r\n    main(None)\r\n  File \"/Users/guido/src/mypy/mypy/main.py\", line 42, in main\r\n    res = type_check_only(sources, bin_dir, options)\r\n  File \"/Users/guido/src/mypy/mypy/main.py\", line 86, in type_check_only\r\n    options=options)\r\n  File \"/Users/guido/src/mypy/mypy/build.py\", line 183, in build\r\n    dispatch(sources, manager)\r\n  File \"/Users/guido/src/mypy/mypy/build.py\", line 1531, in dispatch\r\n    process_graph(graph, manager)\r\n  File \"/Users/guido/src/mypy/mypy/build.py\", line 1768, in process_graph\r\n    process_stale_scc(graph, scc)\r\n  File \"/Users/guido/src/mypy/mypy/build.py\", line 1856, in process_stale_scc\r\n    graph[id].write_cache()\r\n  File \"/Users/guido/src/mypy/mypy/build.py\", line 1512, in write_cache\r\n    self.manager)\r\n  File \"/Users/guido/src/mypy/mypy/build.py\", line 862, in write_cache\r\n    data = tree.serialize()\r\n  File \"/Users/guido/src/mypy/mypy/nodes.py\", line 271, in serialize\r\n    'names': self.names.serialize(self._fullname),\r\n  File \"/Users/guido/src/mypy/mypy/nodes.py\", line 2265, in serialize\r\n    data[key] = value.serialize(fullname, key)\r\n  File \"/Users/guido/src/mypy/mypy/nodes.py\", line 2211, in serialize\r\n    data['node'] = self.node.serialize()\r\n  File \"/Users/guido/src/mypy/mypy/nodes.py\", line 671, in serialize\r\n    'type': None if self.type is None else self.type.serialize(),\r\n  File \"/Users/guido/src/mypy/mypy/types.py\", line 837, in serialize\r\n    'items': [t.serialize() for t in self.items()],\r\n  File \"/Users/guido/src/mypy/mypy/types.py\", line 837, in \u003clistcomp\u003e\r\n    'items': [t.serialize() for t in self.items()],\r\n  File \"/Users/guido/src/mypy/mypy/types.py\", line 763, in serialize\r\n    for t in self.arg_types],\r\n  File \"/Users/guido/src/mypy/mypy/types.py\", line 763, in \u003clistcomp\u003e\r\n    for t in self.arg_types],\r\n  File \"/Users/guido/src/mypy/mypy/types.py\", line 1079, in serialize\r\n    'items': [t.serialize() for t in self.items],\r\n  File \"/Users/guido/src/mypy/mypy/types.py\", line 1079, in \u003clistcomp\u003e\r\n    'items': [t.serialize() for t in self.items],\r\n  File \"/Users/guido/src/mypy/mypy/types.py\", line 496, in serialize\r\n    assert not self.id.is_meta_var()\r\nAssertionError\r\n```","author":{"url":"https://github.com/gvanrossum","@type":"Person","name":"gvanrossum"},"datePublished":"2017-02-03T23:14:20.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":1},"url":"https://github.com/2804/mypy/issues/2804"}