Mistype of empty tuples

[rtpg]

Perhaps I'm missing some subtlety here but mypy complains about two usages for empty tuples that I do not believe are invalid:

print( ()  + (2,3,))
foo = True
print( ((1,2,) if foo else ()) + (2,3,))

This gives:

my_test.py:1: error: Unsupported operand types for + ("Tuple[]" and "Tuple[int, int]")
my_test.py:3: error: Unsupported left operand type for + ("object")

Typing this out, it feels like it might be an issue with generics. This started getting reported in 0.530 for me.

[JelleZijlstra]

I think this is an old issue, #224. Your description makes it sound like this is a regression in 0.530 though, can you confirm that? If so, this should be high priority to fix.

[rtpg]

This was not getting caught by our CI with 0.521, but an instance of this started getting caught in 0.530 so I believe it is a regression.

[gvanrossum]

I tried to bisect this and found it still occurs back with version 0.501, so don't think this is a regression. Probably there was some other reason why the real code that you were checking passed (perhaps some other bug make mypy ignore some code).

FWIW the example I tried was:

a = () + (1,2)

This gives two errors:

__tmp__.py:1: error: Unsupported operand types for + ("tuple" and "Tuple[int, int]")
__tmp__.py:1: error: Need type annotation for variable

[ilevkivskyi]

Since this is not a regression, I propose to close this as a duplicate of #224