Executing following snippet throws an exception.
{{CriteriaBuilder builder = entityManager.getCriteriaBuilder();
CriteriaUpdate<Person> upd = builder.createCriteriaUpdate(Person.class);
upd.from(Person.class);
upd.set(Person_.subject, builder.nullLiteral(Subject.class));}}

Stacktrace:
{{java.lang.IllegalArgumentException: Could not convert java type [org.hibernate.bugs.entity.Subject] to Hibernate type
at org.hibernate.query.criteria.internal.compile.CriteriaCompiler$1.getCastType(CriteriaCompiler.java:120)
at org.hibernate.query.criteria.internal.expression.NullLiteralExpression.render(NullLiteralExpression.java:31)
at org.hibernate.query.criteria.internal.CriteriaUpdateImpl.renderAssignments(CriteriaUpdateImpl.java:133)
at org.hibernate.query.criteria.internal.CriteriaUpdateImpl.renderQuery(CriteriaUpdateImpl.java:118)
at org.hibernate.query.criteria.internal.AbstractManipulationCriteriaQuery.interpret(AbstractManipulationCriteriaQuery.java:102)
at org.hibernate.query.criteria.internal.compile.CriteriaCompiler.compile(CriteriaCompiler.java:127)
at org.hibernate.internal.SessionImpl.createQuery(SessionImpl.java:3591)
at org.hibernate.internal.SessionImpl.createQuery(SessionImpl.java:203)
at org.hibernate.bugs.JPAUnitTestCase.couldNotConvertJavaType(JPAUnitTestCase.java:40)}}

Hibernate ORM versions 5.1.0 and 5.2.0 are OK.
Test case included.