type not generic when running with Python < 3.9

[srittau]

Bug Report

Please consider the following stub file:

x: dict[str, str]
y: type[str]

When checking it with mypy 0.820+dev.1e96f1df48a6e06ba598fa8230b96671b206cba0 and Python 3.9.4, it passes. Using Python 3.8.9 on the other hand, produces the following output:

foo.pyi:2: error: "type" expects no type arguments, but 1 given

It's weird that generic dict works, but generic type doesn't. (Although I'd expect both to work with any Python version.)

This came up during python/typeshed#5192.

[srittau]

@JukkaL This doesn't seem to fixed in mypy 0.930:

$ mypy --version
mypy 0.930
$ cat foo.pyi 
x: dict[str, str]
y: type[str]
$ mypy --python-version=3.9 foo.pyi 
Success: no issues found in 1 source file
$ mypy --python-version=3.8 foo.pyi 
foo.pyi:2: error: "type" expects no type arguments, but 1 given
Found 1 error in 1 file (checked 1 source file)

(I tested it with both Python 3.9.6 and 3.6.14.)

[AlexWaygood]

@JukkaL This doesn't seem to fixed in mypy 0.930:

Interestingly, it appears to be fixed for .py files, but not for .pyi files. This, in a .py file, will pass using Python 3.7:

from __future__ import annotations
foo: type[str]

But this, in a .pyi file, fails using Python <= 3.8:

foo: type[str]

Many similar errors can be found in the CI output for python/typeshed#6681.

[AlexWaygood]

Cc. @sobolevn

[sobolevn]

Sorry, I cannot not reopen issues, but here's my PR: #11863

[hauntsaninja]

Thanks to sobolevn this should be fixed for pyi with old Pythons!