Sealed classes: suggest 'sealed' modifier for inner classes (IDEA-249580)

GitOrigin-RevId: 7ea47ec84d6250868ed605e12d169f13ab373b3d

java/java-impl/src/com/intellij/codeInsight/completion/ModifierChooser.java

@@ -39,6 +39,25 @@ public final class ModifierChooser {
     {PsiKeyword.TRANSIENT}
   };
 
+  private static final String[][] CLASS_15_MEMBER_MODIFIERS = {
+    {PsiKeyword.PUBLIC, PsiKeyword.PROTECTED, PsiKeyword.PRIVATE},
+    {PsiKeyword.STATIC},
+    {PsiKeyword.FINAL, PsiKeyword.ABSTRACT},
+    {PsiKeyword.SEALED, PsiKeyword.NON_SEALED},
+    {PsiKeyword.NATIVE},
+    {PsiKeyword.SYNCHRONIZED},
+    {PsiKeyword.STRICTFP},
+    {PsiKeyword.VOLATILE},
+    {PsiKeyword.TRANSIENT}
+  };
+
+  private static final String[][] INTERFACE_15_MEMBER_MODIFIERS = {
+    {PsiKeyword.PUBLIC, PsiKeyword.PROTECTED, PsiKeyword.PRIVATE},
+    {PsiKeyword.STATIC, PsiKeyword.DEFAULT},
+    {PsiKeyword.FINAL, PsiKeyword.ABSTRACT},
+    {PsiKeyword.SEALED, PsiKeyword.NON_SEALED}
+  };
+
   private static final String[][] INTERFACE_9_MEMBER_MODIFIERS = {
     {PsiKeyword.PUBLIC, PsiKeyword.PROTECTED, PsiKeyword.PRIVATE},
     {PsiKeyword.STATIC, PsiKeyword.DEFAULT},
@@ -82,10 +101,13 @@ public final class ModifierChooser {
   }
 
   public static String[] addMemberModifiers(PsiModifierList list, final boolean inInterface, @NotNull PsiElement position) {
-    return addKeywords(list, inInterface ? getInterfaceMemberModifiers(position) : CLASS_MEMBER_MODIFIERS);
+    return addKeywords(list, inInterface ? getInterfaceMemberModifiers(position) : getClassMemberModifiers(position));
   }
 
   private static String[][] getInterfaceMemberModifiers(@NotNull PsiElement list) {
+    if (PsiUtil.getLanguageLevel(list).isAtLeast(LanguageLevel.JDK_15_PREVIEW)) {
+      return INTERFACE_15_MEMBER_MODIFIERS;
+    }
     if (PsiUtil.isLanguageLevel9OrHigher(list)) {
       return INTERFACE_9_MEMBER_MODIFIERS;
     }
@@ -95,6 +117,13 @@ public final class ModifierChooser {
     return INTERFACE_MEMBER_MODIFIERS;
   }
 
+  private static String[][] getClassMemberModifiers(@NotNull PsiElement list) {
+    if (PsiUtil.getLanguageLevel(list).isAtLeast(LanguageLevel.JDK_15_PREVIEW)) {
+      return CLASS_15_MEMBER_MODIFIERS;
+    }
+    return CLASS_MEMBER_MODIFIERS;
+  }
+
   private static String[] addKeywords(PsiModifierList list, String[][] keywordSets) {
     final List<String> ret = new ArrayList<>();
     for (int i = 0; i < keywordSets.length; i++) {

java/java-tests/testData/codeInsight/completion/keywords/innerClassSealedModifier.java

@@ -0,0 +1,3 @@
+class Foo {
+  <caret> class Bar {}
+}

java/java-tests/testData/codeInsight/completion/keywords/interfaceInnerClassSealedModifier.java

@@ -0,0 +1,3 @@
+interface Foo {
+  private <caret> class Bar {}
+}

java/java-tests/testSrc/com/intellij/java/codeInsight/completion/KeywordCompletionTest.java

@@ -200,6 +200,8 @@ public class KeywordCompletionTest extends LightCompletionTestCase {
   public void testSealedModifier() {setLanguageLevel(LanguageLevel.JDK_15_PREVIEW);  doTest(1, "sealed"); }
   public void testPermitsList() {setLanguageLevel(LanguageLevel.JDK_15_PREVIEW);  doTest(1, "permits"); }
   public void testEnumPermitsList() {setLanguageLevel(LanguageLevel.JDK_15_PREVIEW);  doTest(0, "permits"); }
+  public void testInnerClassSealedModifier() {setLanguageLevel(LanguageLevel.JDK_15_PREVIEW);  doTest(1, "sealed");}
+  public void testInterfaceInnerClassSealedModifier() {setLanguageLevel(LanguageLevel.JDK_15_PREVIEW);  doTest(1, "sealed");}
 
   public void testOverwriteCatch() {
     configureByTestName();