void (@Nullable PsiCaseLabelElementList from, @Nullable PsiCaseLabelElementList to, boolean mergeWithDefault) { if (from == null || to == null) return; for (PsiCaseLabelElement caseValue : from.getElements()) { if (mergeWithDefault) { to.addBefore(caseValue, to.getFirstChild()); } else { to.addAfter(caseValue, to.getLastChild()); } } }