The new Didnt linter's description states Corrects dinttodidn't after subject pronouns.
Which would make sense. Subject pronouns are: I, we, you, he, she, it, they.
But the code is actually .then_personal_pronoun()
This will probably generate false positives since the subject pronouns are a subset of the personal pronouns. Personal pronouns are those which have an inherent 1st person/2nd person/3rd person property, which includes at least the object pronouns: me, us, him, her, them, which normally don't make sense before "didn't".
False positives are probably very unlikely. I'd file a PR but being behind the GFW without a proper VPN makes even filing an issue difficult right now.