If an @IndexedEmbedded field is delcared by an interface or a unmapped superclass, there is no way hibernate-search can resolve the concrete class (compare to org.hibernate.annotations.Target or the targetEntity parameter for @To annotations). The attached patch solves this issue by introducing a IndexedTarget annotation which, much like @Target, expects the mapped class as its single parameter. See test/org/hibernate/search/test/embedded/
changes for a simple example.
This issue was first exmplained in http://forum.hibernate.org/viewtopic.php?p=2366118