IsValid rule not being used inside linter?

Is there a particular reason why this rule isn't being run in the linter?
I feel like this is the most important rule to be run.

I also don't see an option that I can pass to add it to the list of rules to check against.

Start by locating the linter entry point and the IsValid rule implementation. Check how the linter selects rules and whether an option can add IsValid to that list. Done means the rule is run by default or can be enabled through a documented option, with the reason for its current behavior clear.

Written by the indexing model from the issue text.