Expected Common Misunderstanding (was: bug: run/3 bug)

[Dean Tribble]

>This build3 is both a 2-arity function and a 3-arity function, in that it 
>has both arities of "run" method.  Though it has both behaviors, there's 
>only one object, and both calls to build3 are invoking that same object.
>
>Unless someone has a super-clever idea, I'd guess we are simply stuck with 
>people often falling into this trap, and all we can do is explain the issue 
>well. 

The super-clever idea is just more diagnostics.  In the example, the
compiler could have issued a warning that the build3 function was being
redefined (and let it proceed).  It could also have complained that the
build3/3 call wasn't defined (again, while accepting the definition).  This
latter analysis is obviously harder!  Having the redefinition one would be
very useful, however.