Add PosArgT typing to trio.run

[jakkdl]

I noticed this when going through the trio-typing test suite. I don't see any reason why this would've been intentionally skipped in #2881, so I suspect it just got missed?

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 99.63%. Comparing base (a7db0e4) to head (945a3b5).

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #3022   +/-   ##
=======================================
  Coverage   99.63%   99.63%           
=======================================
  Files         120      120           
  Lines       17865    17865           
  Branches     3216     3216           
=======================================
  Hits        17800    17800           
  Misses         46       46           
  Partials       19       19           

Files with missing lines	Coverage Δ
src/trio/_core/_run.py	99.38% <ø> (ø)
src/trio/_core/_tests/test_run.py	100.00% <100.00%> (ø)

[Zac-HD]

Looks good to me!

Should we consider moving over some of the trio-typing test suite, since apparently that catches some issues that the trio tests don't?

[TeamSpen210]

Must have been missed, yes.

[A5rocks]

Maybe add a type test.

Feel free to merge this whether or not you add one though.

[CoolCat467]

Looks great!

[jakkdl]

Looks good to me!

Should we consider moving over some of the trio-typing test suite, since apparently that catches some issues that the trio tests don't?

There's not much that's worth adapting, I don't think we want to adapt their method of running internal mypy functions, so it would consist of copying and adapting the test-data. But we already cover most everything:

• We don't care for async_generator tests
• outcome has its own type tests
• we already have type tests for trio.Path and TaskStatus
• trio-basic:
  • we have type tests for open_memory_channel
  • we have type tests for nursery.start_soon

The only things left were run, that trio-typing raised a typing error if you tried to instantiate Cancelled, Nursery.start, and some trivial stuff that would raise typechecking errors when we run mypy on our test suite.