unpacking assignment with self annotated as typing.Self in typing.NamedTuple subclass method causes mypy internal error

[Floozutter]

Crash Report
Inside of typing.NamedTuple subclass methods, unpacking assignments with self annotated as typing.Self on the right-hand side causes mypy to fail (internal error).

Traceback

$ mypy --show-traceback foo.py
foo.py:6: 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: 1.9.0
Traceback (most recent call last):
  File "<frozen runpy>", line 198, in _run_module_as_main
  File "<frozen runpy>", line 88, in _run_code
  File "mypy\checker.py", line 595, in accept
  File "mypy\nodes.py", line 1310, in accept
  File "mypy\checker.py", line 2823, in visit_assignment_stmt
  File "mypy\checker.py", line 2878, in check_assignment
  File "mypy\checker.py", line 3580, in check_assignment_to_multiple_lvalues
  File "mypy\checker.py", line 3658, in check_multi_assignment
  File "mypy\checker.py", line 3797, in check_multi_assignment_from_tuple
AssertionError:
foo.py:6: : note: use --pdb to drop into pdb

To Reproduce

import typing

class Foo(typing.NamedTuple):
    bar: int
    def baz(self: typing.Self) -> None:
        _ ,= self

mypy-play gist
mypy-play playground

Alternate example showing that this can occur even when self is not directly annotated as typing.Self:
alternate example mypy-play gist
alternate example mypy-play playground

Your Environment

• Mypy version used: 1.9.0
• Mypy command-line flags: --show-traceback
• Mypy configuration options from mypy.ini (and other config files):
• Python version used: 3.12.2
• Operating system and version: Microsoft Windows 11 Home

[Floozutter]

Previously, I opened issue #17009 with the wrong label "bug". I closed that issue and opened this with the correct label "crash".