Subscript op on TypeAlias to Enum is misinterpreted

Bug Report

Scanning code that makes use of an alias for an Enum class flags an error.

I see several similar issues in the GitHub issue list, e.g.
https://github.com/python/mypy/issues/14281
https://github.com/python/mypy/issues/13337

The error messages in those tickets is different however.

To Reproduce
Gist

Expected Behavior

No error

Actual Behavior

main.py:14: error: Type application targets a non-generic function or class
main.py:14: error: Variable "name" is not valid as a type
main.py:14: note: See https://mypy.readthedocs.io/en/stable/common_issues.html#variables-vs-type-aliases
Found 2 errors in 1 file (checked 1 source file)
Your Environment

• Mypy version used: 0.971
• Mypy command-line flags: none
• Mypy configuration options from mypy.ini (and other config files): none
• Python version used: 3.6.9 (I know, I know)

Inizia dal Gist collegato e riproduci le diagnosi riportate usando mypy 0.971, quindi traccia il modo in cui il checker risolve l’alias di tipo Enum e l’espressione di indicizzazione. Il lavoro è completato quando la riproduzione non produce errori, preservando al contempo la gestione corretta dei tipi non generici.