goran.hultgren at bluefish.se wrote:
> 
> Core replacements - [...] Packages here can depend on both packages
> in core and in Core replacements. But when moved into core they can
> of course only depend on packages in core.

It would make sense to me for core replacements to be allowed to
depend on packages in Extra, with the understanding that this would
significantly raise the barrier for moving such packages to Core, as
that would require moving also the given Extras to Core.  With that in
mind:

> What if we put Traits in "Extra" then? Sure, that is a compromise
> that may work. But then we will loose a lot of the real good use of
> Traits - to untangle our core packages like for example Collections
> or Morphic. Because we can't have packages in core depending on
> packages outside of core. So that doesn't really sound like an
> interesting option.

Clearly Core packages couldn't depend on Traits in this case, but Core
Replacements could.  Isn't Core Replacements exactly the right place
for a redesigned Morphic or Collection heirarchy to live, initially?
Traits would simply need to be moved to Core at such a time as one of
these redesigns was moved to Core.  By contrast, placing Traits in
Core Replacements doesn't make as much sense because it doesn't
replace or conflict with Core behaviors.  "Extra" seems like the right
place to me.

-Jesse