[java-highlighting] IDEA-340074 Return name for classes inside implicit classes

- fix Make static incorrect works with classes inside implicitly declared classes

GitOrigin-RevId: a16063a97735065761868d4e3da68220293a4d51

java/java-psi-impl/src/com/intellij/psi/impl/source/PsiClassImpl.java

@@ -156,6 +156,8 @@ public class PsiClassImpl extends JavaStubPsiElement<PsiClassStub<?>> implements
       return StringUtil.getQualifiedName(((PsiJavaFile)parent).getPackageName(), StringUtil.notNullize(getName()));
     }
     if (parent instanceof PsiClass) {
+      //it cannot be referenced outside ImplicitClass
+      if (parent instanceof PsiImplicitClass) return StringUtil.notNullize(getName());
       String parentQName = ((PsiClass)parent).getQualifiedName();
       if (parentQName == null) return null;
       return StringUtil.getQualifiedName(parentQName, StringUtil.notNullize(getName()));

java/java-tests/testData/ig/com/siyeh/igtest/memory/inner_class_may_be_static/ImplicitClassNoFix.after.java

@@ -0,0 +1,7 @@
+private static class Nested {
+}
+
+void main() {
+  new Nested();
+}
+

java/java-tests/testData/ig/com/siyeh/igtest/memory/inner_class_may_be_static/ImplicitClassNoFix.java

@@ -0,0 +1,7 @@
+private class <warning descr="Inner class 'Nested' may be 'static'">N<caret>ested</warning> {
+}
+
+void main() {
+  new Nested();
+}
+

java/java-tests/testSrc/com/siyeh/ig/memory/InnerClassMayBeStaticInspectionTest.java

@@ -30,6 +30,13 @@ public class InnerClassMayBeStaticInspectionTest extends LightJavaInspectionTest
     });
   }
 
+  public void testImplicitClassNoFix() {
+    IdeaTestUtil.withLevel(getModule(), LanguageLevel.JDK_21_PREVIEW, () -> {
+      doTest();
+      checkQuickFixAll();
+    });
+  }
+
   @Nullable
   @Override
   protected InspectionProfileEntry getInspection() {