equalsButDifferent: anEntry
    "test the equality between two DIFFERENT entries"

    ( self == anEntry) ifTrue: [ ^false ].

    ((key = anEntry key) and: [ (type = anEntry type) ]) ifFalse: [ ^false ].

    (self size = anEntry size) ifFalse: [ ^false ].

    fields do:
        [:each | ((anEntry at: each key) rawValue = each rawValue)
            ifFalse:
                [ ^false ]].

    ^true.