Inline configuration for a newer Python version crashes for union syntax on types (PEP 604) #18450
Description
Crash Report & To Reproduce
Running the following under mypy installed on a Python 3.9 runtime causes a crash:
# mypy: python-version=3.10
a = int | strTo clarify, setting the equivalent of python-version=3.10 doesn't cause a crash if it was done in the mypy configuration file or command line flags.
As an aside, the docs do note that python-version should only be set in the [global] section of configuration files. Maybe attempts to set global-only sections inline in Python sources should also show an inline error when running mypy? Apart from this python-version option in this case, setting such options inline usually "work", but they seem to be applied across the entirety of all files that are type-checked, and side-effects caused by these options can be difficult to trace the origin of.
Traceback
See mypy playground:
Traceback (most recent call last):
File "<frozen runpy>", line 198, in _run_module_as_main
File "<frozen runpy>", line 88, in _run_code
File "/layers/google.python.pip/pip/lib/python3.12/site-packages/mypy/__main__.py", line 37, in <module>
console_entry()
File "/layers/google.python.pip/pip/lib/python3.12/site-packages/mypy/__main__.py", line 15, in console_entry
main()
File "/layers/google.python.pip/pip/lib/python3.12/site-packages/mypy/main.py", line 119, in main
res, messages, blockers = run_build(sources, options, fscache, t0, stdout, stderr)
File "/layers/google.python.pip/pip/lib/python3.12/site-packages/mypy/main.py", line 203, in run_build
res = build.build(sources, options, None, flush_errors, fscache, stdout, stderr)
File "/layers/google.python.pip/pip/lib/python3.12/site-packages/mypy/build.py", line 191, in build
result = _build(
File "/layers/google.python.pip/pip/lib/python3.12/site-packages/mypy/build.py", line 267, in _build
graph = dispatch(sources, manager, stdout)
File "/layers/google.python.pip/pip/lib/python3.12/site-packages/mypy/build.py", line 2935, in dispatch
process_graph(graph, manager)
File "/layers/google.python.pip/pip/lib/python3.12/site-packages/mypy/build.py", line 3333, in process_graph
process_stale_scc(graph, scc, manager)
File "/layers/google.python.pip/pip/lib/python3.12/site-packages/mypy/build.py", line 3434, in process_stale_scc
graph[id].type_check_first_pass()
File "/layers/google.python.pip/pip/lib/python3.12/site-packages/mypy/build.py", line 2307, in type_check_first_pass
self.type_checker().check_first_pass()
File "/layers/google.python.pip/pip/lib/python3.12/site-packages/mypy/checker.py", line 467, in check_first_pass
self.accept(d)
File "/layers/google.python.pip/pip/lib/python3.12/site-packages/mypy/checker.py", line 576, in accept
stmt.accept(self)
File "/layers/google.python.pip/pip/lib/python3.12/site-packages/mypy/nodes.py", line 1345, in accept
return visitor.visit_assignment_stmt(self)
File "/layers/google.python.pip/pip/lib/python3.12/site-packages/mypy/checker.py", line 2998, in visit_assignment_stmt
self.check_assignment(s.lvalues[-1], s.rvalue, s.type is None, s.new_syntax)
File "/layers/google.python.pip/pip/lib/python3.12/site-packages/mypy/checker.py", line 3176, in check_assignment
rvalue_type = self.check_simple_assignment(lvalue_type, rvalue, context=rvalue)
File "/layers/google.python.pip/pip/lib/python3.12/site-packages/mypy/checker.py", line 4347, in check_simple_assignment
rvalue_type = self.expr_checker.accept(
File "/layers/google.python.pip/pip/lib/python3.12/site-packages/mypy/checkexpr.py", line 5903, in accept
typ = node.accept(self)
File "/layers/google.python.pip/pip/lib/python3.12/site-packages/mypy/nodes.py", line 2108, in accept
return visitor.visit_op_expr(self)
File "/layers/google.python.pip/pip/lib/python3.12/site-packages/mypy/checkexpr.py", line 3411, in visit_op_expr
return self.accept(e.analyzed)
File "/layers/google.python.pip/pip/lib/python3.12/site-packages/mypy/checkexpr.py", line 5903, in accept
typ = node.accept(self)
^^^^^^^^^^^^^^^^^
File "/layers/google.python.pip/pip/lib/python3.12/site-packages/mypy/nodes.py", line 2710, in accept
return visitor.visit_type_alias_expr(self)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/layers/google.python.pip/pip/lib/python3.12/site-packages/mypy/checkexpr.py", line 4785, in visit_type_alias_expr
return self.alias_type_in_runtime_context(alias.node, ctx=alias, alias_definition=True)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/layers/google.python.pip/pip/lib/python3.12/site-packages/mypy/checkexpr.py", line 4849, in alias_type_in_runtime_context
return self.chk.named_generic_type("types.UnionType", item.items)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/layers/google.python.pip/pip/lib/python3.12/site-packages/mypy/checker.py", line 7102, in named_generic_type
info = self.lookup_typeinfo(name)
^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/layers/google.python.pip/pip/lib/python3.12/site-packages/mypy/checker.py", line 7109, in lookup_typeinfo
sym = self.lookup_qualified(fullname)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/layers/google.python.pip/pip/lib/python3.12/site-packages/mypy/checker.py", line 7211, in lookup_qualified
raise KeyError(msg.format(last, name))
KeyError: "Failed qualified lookup: 'UnionType' (fullname = 'types.UnionType')."
main.py:3: 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: 1.15.0+dev.9274a07bfa3c92b38fe35cf9736beb068ae9196b
main.py:3: : note: use --pdb to drop into pdb
Your Environment
- Mypy version used: 1.14.1, master
- Mypy command-line flags:
--show-traceback - Mypy configuration options from
mypy.ini(and other config files): None - Python version used: 3.9