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

[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.