Skip to content

Trying to define a tuple with at least 1 element causes a crash if you try to define a tuple with *exactly* 1 element #16425

@nytelytee

Description

@nytelytee

Crash Report

Trying to define a tuple with at least 1 element (tuple[T, *tuple[T, ...]]) causes a crash if you try to define a tuple with exactly 1 element.

Traceback

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/python3.11/site-packages/mypy/__main__.py", line 37, in <module>
    console_entry()
  File "/layers/google.python.pip/pip/lib/python3.11/site-packages/mypy/__main__.py", line 15, in console_entry
    main()
  File "/layers/google.python.pip/pip/lib/python3.11/site-packages/mypy/main.py", line 100, in main
    res, messages, blockers = run_build(sources, options, fscache, t0, stdout, stderr)
  File "/layers/google.python.pip/pip/lib/python3.11/site-packages/mypy/main.py", line 182, in run_build
    res = build.build(sources, options, None, flush_errors, fscache, stdout, stderr)
  File "/layers/google.python.pip/pip/lib/python3.11/site-packages/mypy/build.py", line 191, in build
    result = _build(
  File "/layers/google.python.pip/pip/lib/python3.11/site-packages/mypy/build.py", line 265, in _build
    graph = dispatch(sources, manager, stdout)
  File "/layers/google.python.pip/pip/lib/python3.11/site-packages/mypy/build.py", line 2943, in dispatch
    process_graph(graph, manager)
  File "/layers/google.python.pip/pip/lib/python3.11/site-packages/mypy/build.py", line 3341, in process_graph
    process_stale_scc(graph, scc, manager)
  File "/layers/google.python.pip/pip/lib/python3.11/site-packages/mypy/build.py", line 3442, in process_stale_scc
    graph[id].type_check_first_pass()
  File "/layers/google.python.pip/pip/lib/python3.11/site-packages/mypy/build.py", line 2311, in type_check_first_pass
    self.type_checker().check_first_pass()
  File "/layers/google.python.pip/pip/lib/python3.11/site-packages/mypy/checker.py", line 481, in check_first_pass
    self.accept(d)
  File "/layers/google.python.pip/pip/lib/python3.11/site-packages/mypy/checker.py", line 591, in accept
    stmt.accept(self)
  File "/layers/google.python.pip/pip/lib/python3.11/site-packages/mypy/nodes.py", line 1308, in accept
    return visitor.visit_assignment_stmt(self)
  File "/layers/google.python.pip/pip/lib/python3.11/site-packages/mypy/checker.py", line 2817, 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/python3.11/site-packages/mypy/checker.py", line 2994, in check_assignment
    rvalue_type = self.check_simple_assignment(lvalue_type, rvalue, context=rvalue)
  File "/layers/google.python.pip/pip/lib/python3.11/site-packages/mypy/checker.py", line 4147, in check_simple_assignment
    rvalue_type = self.expr_checker.accept(
  File "/layers/google.python.pip/pip/lib/python3.11/site-packages/mypy/checkexpr.py", line 5716, in accept
    typ = node.accept(self)
          ^^^^^^^^^^^^^^^^^
  File "/layers/google.python.pip/pip/lib/python3.11/site-packages/mypy/nodes.py", line 2267, in accept
    return visitor.visit_tuple_expr(self)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/layers/google.python.pip/pip/lib/python3.11/site-packages/mypy/checkexpr.py", line 4929, in visit_tuple_expr
    if isinstance(type_context, TupleType) and self.tuple_context_matches(e, type_context):
                                               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/layers/google.python.pip/pip/lib/python3.11/site-packages/mypy/checkexpr.py", line 4907, in tuple_context_matches
    expr_star_index = next(i for i, lv in enumerate(expr.items) if isinstance(lv, StarExpr))
                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
StopIteration: 

main.py:5: 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: 1.8.0+dev.a1864d4fa498ccd8773c2247eb62282644174d26
main.py:5: : note: use --pdb to drop into pdb

To Reproduce

The line defining z in the playground is the one that causes the crash.
https://mypy-play.net/?mypy=master&python=3.12&flags=show-traceback&gist=6f394a4996dfcb54c263e1e72e3710a1

Your Environment

I don't believe any of this matters in this instance because the same issue happens on the playground as well.

Metadata

Metadata

Assignees

No one assigned

    Labels

    Projects

    No projects

    Milestone

    No milestone

    Relationships

    None yet

    Development

    No branches or pull requests

    Issue actions