Migrated issue, originally created by Boris Kozinsky (@bkoz37)

When doing multiple joins with single-inheritance objects, type/discriminator checking has issues. In some cases, the checking is not done when "from_joinpoint = True" is used. In other cases, when explicit two-argument joins are used, the type checking is on the wrong alias. See tests 8 and 9 in attached test_inh_query.py file.

Attachments: test_inh_query.py | test_inh_def.py