covariance - Java vs Smalltalk - covarince and contravariance -

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does smalltalk support covariance , contravariance? these concepts apply language?

smalltalk strictly , dynamically typed. cares if parameter object responds messages gets send. if not, raises dnu (does not understand) @ run time when message sent (which can handle either hand, or respond in code). @ compile time, every parameter object, , allowed send message object.


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