Pylance doesn't color classes' generic types for 3.12 syntax

[mtsokol]

As the title says the new generic class syntax seems to not be supported class MyClass[T]:, contrary to the previous formula class MyClass(Generic[T]):.

New syntax: https://docs.python.org/3/library/typing.html#typing.TypeVar

Environment data

• Pylance version: 2025.8.2
• OS and version: MacOS 15.6.1
• Python version: Python 3.12.11

Code Snippet

from typing import TypeVar, Generic

T = TypeVar("T", int, bytes)


class AA[T]:
    def __init__(self, arg: T):
        self.arg: T = arg


class BB(Generic[T]):
    def __init__(self, arg: T):
        self.arg: T = arg

Expected behavior

T type in both class versions should be recognized and colored in light blue.

Actual behavior

With the new syntax (supported since 3.12) the T isn't recognized (which is what white color suggest).

[github-actions]

Hi @mtsokol, I'm an AI Support assistant here to help with your issue. While the team reviews your request, I wanted to provide some possible tips and documentation that might help you in the meantime.

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Potential Duplicate Issues – These issues may be duplicates of your report, but may differ in some of the details.

• Could not rename all references when using new Generic syntax. Could not rename all references when using new Generic syntax #6893

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Similar Issues (FYI only, not solutions)

The following issues may or may not be related to your report. They are provided for reference only, as they may describe similar symptoms, affect the same feature, or address related concerns, but may not be the same issue.

• Type var does not match on generic functions defined within classes – alternative PEP 695 generic class syntax support in Pyright. Type var does not match on generic functions defined within classes pyright#10004

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[mtsokol]

I got a response from Typing Q&A and it turns out that the T in the new syntax comes from a new scope so it doesn't refer to the T defined at the beginning: python/typing#2088 (comment)

My opinion is that the T here should be colored in light blue. IIUC white says that it might not be defined. But with the new syntax it is defined with the class definition, so T should be the same color as arg.