T item = itemInfo.value;
    T related = relatedInfo.value;
    assertWithTemplate(
        "$ITEM must be $RELATIONSHIP to $OTHER",
        itemInfo,
        relatedInfo,
        equivalence.equivalent(item, related));

    int itemHash = equivalence.hash(item);
    int relatedHash = equivalence.hash(related);
    assertWithTemplate(
        "the $HASH ("
            + itemHash