LGTM.com - false positive - Typescript (infer T extends U) pattern should be valid.

[Jym77]

Description of the false positive
This alert is flagging a missing ? in a (infer T extends Value) TypeScript pattern, likely expecting the extends keyword to be part of a ternary extends Value ? … : … construction.
The infer T extends Value pattern is valid TypeScript that I was told to use as a workaround to a TS error, see this TS issue.

So, I guess this should be considered as valid syntax.

URL to the alert on the project page on LGTM.com
(tried to, but the alert is currently on a branch and I couldn't find how to tell LGTM.com to hook up on a branch rather than the latest released version 😕 )

[erik-krogh]

Your example is only valid in TypeScript 4.7, and the code-scanning workflow was using TypeScript 4.6, which caused the error.

We already have support for TypeScript 4.7, but that was only released as of 2.9.4 (released 3 hours ago).
It will still take a while before 2.9.4 is used in your code-scanning workflows.

The alert should fix itself once you run an analysis using the new 2.9.4 version of CodeQL.

So thanks for the report, but it has already been fixed.

[Jym77]

Thanks for the answer.
Missed that point indeed 😖