Can't alias a union of tuples

[dmoisset]

Bug Report

When I create a type alias with a union of two tuple types, I get an error about the tuple type being applied to too many generic arguments.

To Reproduce

from typing import TypeAlias

mypair = tuple[int, int] | tuple[str, str]

https://mypy-play.net/?mypy=latest&python=3.10&gist=f2a322b4ac47de32fe0d3c06a2fa6fc8

Expected Behavior

The above program should type check correctly and define an alias

Actual Behavior

main.py:3: error: Type application has too many types (1 expected)  [misc]
Found 1 error in 1 file (checked 1 source file)

Your Environment

• mypy 0.990
• no command line flags
• no configuration file
• Python version used: 3.11

[AlexWaygood]

Duplicate of #11098