Crash in match statement with literals #13666
Description
Crash Report
Mypy crashes when run over a match statement.
Traceback
a05.py:10: error: INTERNAL ERROR -- Please try using mypy master on GitHub:
https://mypy.readthedocs.io/en/stable/common_issues.html#using-a-development-mypy-build
Please report a bug at https://github.com/python/mypy/issues
version: 0.990+dev.7c14feedd2a6889d9eab8b0ac8dc8aab630bbed3
Traceback (most recent call last):
File "/Users/tintvrtkovic/hr/shop-service/.venv/bin/mypy", line 8, in <module>
sys.exit(console_entry())
File "/Users/tintvrtkovic/hr/shop-service/.venv/lib/python3.10/site-packages/mypy/__main__.py", line 15, in console_entry
main()
File "/Users/tintvrtkovic/hr/shop-service/.venv/lib/python3.10/site-packages/mypy/main.py", line 95, in main
res, messages, blockers = run_build(sources, options, fscache, t0, stdout, stderr)
File "/Users/tintvrtkovic/hr/shop-service/.venv/lib/python3.10/site-packages/mypy/main.py", line 174, in run_build
res = build.build(sources, options, None, flush_errors, fscache, stdout, stderr)
File "/Users/tintvrtkovic/hr/shop-service/.venv/lib/python3.10/site-packages/mypy/build.py", line 188, in build
result = _build(
File "/Users/tintvrtkovic/hr/shop-service/.venv/lib/python3.10/site-packages/mypy/build.py", line 271, in _build
graph = dispatch(sources, manager, stdout)
File "/Users/tintvrtkovic/hr/shop-service/.venv/lib/python3.10/site-packages/mypy/build.py", line 2885, in dispatch
process_graph(graph, manager)
File "/Users/tintvrtkovic/hr/shop-service/.venv/lib/python3.10/site-packages/mypy/build.py", line 3269, in process_graph
process_stale_scc(graph, scc, manager)
File "/Users/tintvrtkovic/hr/shop-service/.venv/lib/python3.10/site-packages/mypy/build.py", line 3370, in process_stale_scc
graph[id].type_check_first_pass()
File "/Users/tintvrtkovic/hr/shop-service/.venv/lib/python3.10/site-packages/mypy/build.py", line 2302, in type_check_first_pass
self.type_checker().check_first_pass()
File "/Users/tintvrtkovic/hr/shop-service/.venv/lib/python3.10/site-packages/mypy/checker.py", line 462, in check_first_pass
self.accept(d)
File "/Users/tintvrtkovic/hr/shop-service/.venv/lib/python3.10/site-packages/mypy/checker.py", line 570, in accept
stmt.accept(self)
File "/Users/tintvrtkovic/hr/shop-service/.venv/lib/python3.10/site-packages/mypy/nodes.py", line 1559, in accept
return visitor.visit_match_stmt(self)
File "/Users/tintvrtkovic/hr/shop-service/.venv/lib/python3.10/site-packages/mypy/checker.py", line 4551, in visit_match_stmt
inferred_types = self.infer_variable_types_from_type_maps(type_maps)
File "/Users/tintvrtkovic/hr/shop-service/.venv/lib/python3.10/site-packages/mypy/checker.py", line 4600, in infer_variable_types_from_type_maps
assert isinstance(node, Var)
AssertionError:
a05.py:10: : note: use --pdb to drop into pdb
To Reproduce
A few code snippets for context (imports omitted for clarity).
This works:
x: Literal["test"]
match x:
case "test":
pass
case _:
assert_never(x)This doesn't type-check (but should), but no crash:
x: tuple[Literal["test"]]
match x:
case ("test",):
pass
case _:
assert_never(x)And finally, the crash:
def x() -> tuple[Literal["test"]]:
...
match x():
case (x,) if x == "test":
pass
case _:
assert_never(1)Your Environment
- Mypy version used: mypy 0.990+dev.7c14feedd2a6889d9eab8b0ac8dc8aab630bbed3 (compiled: no)
- Mypy command-line flags: --show-traceback
- Mypy configuration options from
mypy.ini(and other config files): - Python version used: 3.10.5
- Operating system and version: macOs