Re: possible bug in TreeMap.sucessor implementation

[Eric Blake]

Dalibor Topic wrote:
> > Since nil is supposed to have children that are also
> > nil it appears
> > that at some point nil.right was assiged a value.  
>
>
> would it be possible to make nil an "ImmutableNode",
> so that such assignments are caught and greeted with
> an Error? that should make your life easier next time
> you have to debug a similar case.

For debugging, yes.  For efficiency, no.  Creating an ImmutableNode 
would require reworking the entire TreeMap class to use method calls, 
rather than field assignments, for manipulating nodes.  Adding 
polymorphic calls is an additional layer of indirection, and will make 
the overall implementation slower.

I still haven't had a good look into the bug, but I have finally got the 
time to spend on it now, and have reproduced it.  So look for a fix by 
the end of the day (I hope).

--
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Eric Blake             address@hidden
  BYU student, free software programmer