CriteriaContext nested() {
    // return new CriteriaContext(entityClass, new DnfExpression(), path, creator, null);
    ImmutableState newState = state.withCurrent(null).withDefaultPartial(state.partial()).withCombiner(Combiner.dnfAnd());
    return new CriteriaContext(null, newState);
  }
Create nested context for lambdas used in {@link WithMatcher} or {@link NotMatcher}.
It is considered new root expression
criteria/common/src/org/immutables/criteria/matcher/CriteriaContext.java