I am missing userful functionality?

> Hello, guys
>
> i want to do a simple thing, which can be expressed by following:
>
> oldClass replaceWith: newClass migrateInstances: [:inst |
>  ... ]
>
> In my case, first, i installing a WeakFinalizationRegistry class,
> and then want to replace an old WeakRegistry class with it,
> silently and painlessly.
>
> I end up with following script:
>
>  | old new oldClass newClass |
>        old := OrderedCollection new.
>        new := OrderedCollection new.
>
>
> "migrate instances"
> WeakRegistry allInstancesDo: [:registry | | newr |
>                old add: registry.
>                newr := WeakFinalizationRegistry basicNew initialize.
>                registry migrateTo: newr.
>                new add: newr ].
>        old asArray elementsForwardIdentityTo: new asArray.
>
> "replace the class"
>
>        oldClass := WeakRegistry.
>        newClass := WeakFinalizationRegistry.
>
>        Smalltalk forgetClass: #WeakFinalizationRegistry logged: false.
>        newClass superclass removeSubclass: newClass.
>        newClass setName: #WeakRegistry.
>        oldClass becomeForward: newClass.
>
> --
>
> it looks a bit hackish, and i wonder how to do that in more 'standard' way.
>
> Initially replacing classes was:
>
>  oldClass removeFromSystem.
>  newClass rename: #WeakRegistry
>
> the problem with that, is that all compiled methods , which was
> referring to old class through association,
> still using it, and to get rid of them i have to recompile them.
>
>
>
> --
> Best regards,
> Igor Stasenko AKA sig.
>