I pushed the tests upstream showing the problem here. See org.hibernate.test.hbm.IndexTest. I marked the failing tests with @FailureExpected.

F. Martin the work around for now would be to explicitly name the column. The problem in the current code is that at the time we are trying to create the IndexConstraintSource we have not yet resolved the implicit column name. And we cannot. The solution will be to delay the handling of indexex (and unique keys) at all until later for hbm.xml binding.