void (@NotNull List<? super PsiCaseLabelElement> elements, @NotNull PsiCaseLabelElement labelElement) { if (labelElement instanceof PsiPattern) { elements.add(labelElement); } else if (labelElement instanceof PsiExpression) { boolean isNullType = isNullType(labelElement); if (isNullType && PsiUtil.getLanguageLevel(labelElement).isAtLeast(LanguageLevel.JDK_20_PREVIEW) && isInCaseNullDefaultLabel(labelElement)) { // JEP 432 // A 'case null, default' label dominates all other switch labels. // // In this case, only the 'default' case will be added to the elements checked for dominance return; } if (isNullType || isConstantLabelElement(labelElement)) { elements.add(labelElement); } } else if (labelElement instanceof PsiDefaultCaseLabelElement) { elements.add(labelElement); } }