in short, implementorsOf:/referencesTo:/ is broken (does not search over the class side of things).
Moreover, depending on the kind of RBEnvironment one is looking at:
allClasses
returns only the classes
or
returns classes and metaclasses
Of course, implementorsOf: is broken because allClasses does not returns
the metaclasses.
I like it when people "normalize" things :(
Thierry
