use LiteralString for Sentinel name

[DetachHead]

see python/typeshed#16094

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 79.53%. Comparing base (83400e9) to head (219ed4f).

❗ There is a different number of reports uploaded between BASE (83400e9) and HEAD (219ed4f). Click for more details.

HEAD has 13 uploads less than BASE

Flag	BASE (83400e9)	HEAD (219ed4f)
3.11	1	0
3.12	1	0
3.10	1	0
3.13	1	0
pypy3.10	1	0
3.9.12	1	0
3.13.0	1	0
3.9	1	0
3.10.4	1	0
pypy3.11	1	0
3.11.0	1	0
3.12.0	1	0
pypy3.9	1	0

@@             Coverage Diff             @@
##             main     #783       +/-   ##
===========================================
- Coverage   97.26%   79.53%   -17.73%     
===========================================
  Files           3        3               
  Lines        7860     7652      -208     
===========================================
- Hits         7645     6086     -1559     
- Misses        215     1566     +1351     

Flag	Coverage Δ
3.10	?
3.10.4	?
3.11	?
3.11.0	?
3.12	?
3.12.0	?
3.13	?
3.13.0	?
3.14	79.53% <ø> (ø)
3.9	?
3.9.12	?
pypy3.10	?
pypy3.11	?
pypy3.9	?

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Files with missing lines	Coverage Δ
src/typing_extensions.py	30.94% <ø> (-63.06%)	⬇️

... and 1 file with indirect coverage changes

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[AlexWaygood]

You have a NameError because you're trying to use LiteralString before it's defined in this file. But honestly I'd just remove the annotation here. We don't run a type checker in CI (this library defines the runtime shims for defining the type system, it would be very hard), and type checkers and typeshed just ignore any type hints that do appear here. Having anything except the most basic, uncontroversial type hints here is confusing because it implies that they're either checked in CI or useful to end users

[DetachHead]

oops, i couldn't find typing_extensions.pyi in the typeshed repo so i assumed the types were defined here, but i guess that was the fault of github's abysmal search. i'll just close this then

[AlexWaygood]

It's (somewhat confusingly) in the stdlib directory in typeshed, because if we pretend it's part of the stdlib type checkers let us use symbols defined there in builtins.pyi (otherwise we'd have to wait until they're defined in the typing module on all supported Python versions)