- A quasi-regression where apparently in 0.8 you can set a class-level
attribute on declarative to simply refer directly to an :class:`.InstrumentedAttribute`
on a superclass or on the class itself, and it
acts more or less like a synonym; in 0.9, this fails to set up enough
bookkeeping to keep up with the more liberalized backref logic
from :ticket:`2789`.  Even though this use case was never directly
considered, it is now detected by declarative at the "setattr()" level
as well as when setting up a subclass, and the mirrored/renamed attribute
is now set up as a :func:`.synonym` instead. [ticket:2900]
- Fixed regression where we don't check the given name against the
correct string class when setting up a backref based on a name,
therefore causing the error "too many values to unpack".  This was
related to the Py3k conversion. [ticket:2901]