[Help-smalltalk] Subclassing dictionary

[Tim Felgentreff]

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Hi

Trying to port the Squeak JSON package I came across rather strange behaviour. 
One of the classes, JsonObject, is a subclass of dictionary. I noticed that 
subclassing Dictionary would throw an error:

st> Dictionary subclass: JsonObject [
st> ]
st> JsonObject new
Object: JsonObject error: should not be implemented in this class, use 
#basicNew instead
SystemExceptions.WrongMessageSent(Exception)>>signal (ExcHandling.st:254)
SystemExceptions.WrongMessageSent class>>signalOn:useInstead: 
(SysExcept.st:1248)
JsonObject class(Behavior)>>basicNew: (Builtins.st:84)
JsonObject class(HashedCollection class)>>primNew: (HashedColl.st:44)
JsonObject class(HashedCollection class)>>new: (HashedColl.st:62)
JsonObject class(Dictionary class)>>new (Dictionary.st:70)
UndefinedObject>>executeStatements (a String:1)
nil

"Dictionary new" works as expected:

st> Dictionary new
Dictionary new (
)
st>

I don't understand the problem here, can somebody please shed some light on 
this?
Thanks
Tim
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