Hibernate parser can't create a HQL query which is using enum with assigned @javax.persistence.Converter. Please, see test case. Example of an exception is:

org.hibernate.QueryException: Could not format constant value to SQL literal: bug.TestEnum.VALUE [FROM bug.TestEntity t WHERE t.testEnum = bug.TestEnum.VALUE]
at org.hibernate.QueryException.generateQueryException(QueryException.java:137)
at org.hibernate.QueryException.wrapWithQueryString(QueryException.java:120)
... more
Caused by: org.hibernate.QueryException: Could not format constant value to SQL literal: bug.TestEnum.VALUE
at org.hibernate.hql.internal.ast.tree.JavaConstantNode.getRenderText(JavaConstantNode.java:91)
at org.hibernate.hql.internal.ast.SqlGenerator.out(SqlGenerator.java:128)
at org.hibernate.hql.internal.antlr.SqlGeneratorBase.simpleExpr(SqlGeneratorBase.java:2942)
... more
Caused by: java.lang.ClassCastException: org.hibernate.type.descriptor.converter.AttributeConverterTypeAdapter cannot be cast to org.hibernate.type.LiteralType
at org.hibernate.hql.internal.ast.tree.JavaConstantNode.getRenderText(JavaConstantNode.java:86)
... 46 more