Closed
Description
Migrated issue, originally created by Michael Bayer (@zzzeek)
if we defer to the dialect to render the type with impl.render_type(), we then only use that impl if the imports are within the "sqlalchemy.dialects" space. this makes no sense, why are we running impl.render_type() then ignoring it? seems like we are hoping that _user_autogenerate_prefix() is perhaps adding to the imports, and generally that's why we aren't just returning impl_rt. external dialects want the render_type() functionality as well.