Make sure you have "Type may be weakened" On, with option "Use righthand type as weakest type" On.
Provide dummy code like:

import org.jetbrains.annotations.NonNls;

public class RightHandIterator {
    public static int exp(Iterable<String> list) {
        int i = 0;
        for (@NonNls String s: list) {
            if ("some".equals(s)) {
                i++;
            }
        }
        return i;
    }
}

Inspection reports s: "Type of parameter may be weakened to Object".
But it seems that with "Use righthand type" option it should not be reported: the type of collection elements is explicitly set to String.

Issue was closed