Unions crash when one of their type parameters is shadowed by the arguments of a function.

[vthemelis]

Things to check first

• I have searched the existing issues and didn't find my bug already reported there

• I have checked that my bug is still present in the latest release

Typeguard version

4.1.3

Python version

Python 3.10.10

What happened?

from typeguard import typechecked
from typing import Union

@typechecked
def foo(int: Union[int, None]):
    print(int)

foo(42)
foo("foo")

raises this:

Traceback (most recent call last):
  File "/Users/vas/.pyenv/versions/3.10.10/lib/python3.10/runpy.py", line 196, in _run_module_as_main
    return _run_code(code, main_globals, None,
  File "/Users/vas/.pyenv/versions/3.10.10/lib/python3.10/runpy.py", line 86, in _run_code
    exec(code, run_globals)
  File "/Users/vas/source/typeguard/example.py", line 11, in <module>
    foo(42)
  File "/Users/vas/source/typeguard/example.py", line 8, in foo
    def foo(int: Union[int, bool]) -> int:
  File "/Users/vas/.pyenv/versions/3.10.10/lib/python3.10/typing.py", line 312, in inner
    return func(*args, **kwds)
  File "/Users/vas/.pyenv/versions/3.10.10/lib/python3.10/typing.py", line 403, in __getitem__
    return self._getitem(self, parameters)
  File "/Users/vas/.pyenv/versions/3.10.10/lib/python3.10/typing.py", line 515, in Union
    parameters = tuple(_type_check(p, msg) for p in parameters)
  File "/Users/vas/.pyenv/versions/3.10.10/lib/python3.10/typing.py", line 515, in <genexpr>
    parameters = tuple(_type_check(p, msg) for p in parameters)
  File "/Users/vas/.pyenv/versions/3.10.10/lib/python3.10/typing.py", line 176, in _type_check
    raise TypeError(f"{msg} Got {arg!r:.100}.")
TypeError: Union[arg, ...]: each arg must be a type. Got 42.

This is related to #337 and #342

How can we reproduce the bug?

As above