child of #14942
I have read check documentation: https://checkstyle.org/checks/coding/equalsavoidnull.html#EqualsAvoidNull
I have downloaded the latest checkstyle from: https://checkstyle.org/cmdline.html#Download_and_Run
I have executed the cli and showed it below, as cli describes the problem better than 1,000 words

public class Test {
    void test(Object obj) {
        if (obj instanceof String _) {
            _.equals("s");   // compile time error, Using '_' as a reference is not allowed
        }
    }
}

we can't call equals() on unnamed variables or patterns so this check is not applicable to them.