#77 Automatically adding instance variables in class method breaks the package

Here's the flow:

1. Create a class method that references an unknown class instance variable; try to save it.
2. Helios prompts you to create it; select Confirm.
3. Error message appears: "JavaScript exception: TypeError: traitOrClass.added is not a function"
4. Click Abandon on that error.
5. Make some other, legal edit so your package is dirty.
6. Try to commit it, error message "nil does not understand #name", package is not committed.

There's no visible code change to revert; this seems unrecoverable except by a refresh, and now whatever edits one has made are lost.

That traitOrClass.added is not a function is scary (but a good pointer as it is clear where this is called).

Bug is upstream: amber/amber#1235, closing.