[java-completion] IDEA-363557 Don't offer classes after dot at class level

GitOrigin-RevId: da52d7093ed80c0eb80ebf11e5f43d2d58a0758e

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

@@ -59,6 +59,7 @@ import com.intellij.psi.impl.light.LightJavaModule;
 import com.intellij.psi.impl.source.PsiJavaCodeReferenceElementImpl;
 import com.intellij.psi.impl.source.PsiLabelReference;
 import com.intellij.psi.impl.source.resolve.JavaResolveUtil;
+import com.intellij.psi.impl.source.tree.JavaElementType;
 import com.intellij.psi.scope.ElementClassFilter;
 import com.intellij.psi.search.GlobalSearchScope;
 import com.intellij.psi.search.ProjectScope;
@@ -88,6 +89,16 @@ public final class JavaCompletionContributor extends CompletionContributor imple
   private static final ElementPattern<PsiElement> UNEXPECTED_REFERENCE_AFTER_DOT = or(
       // dot at the statement beginning
       psiElement().afterLeaf(".").insideStarting(psiExpressionStatement()),
+      //example: class A{ .something }
+      psiElement().afterLeaf(".")
+        .insideStarting(psiElement(JavaElementType.TYPE))
+        .afterLeafSkipping(psiElement().andOr(
+                             psiElement().whitespace(),
+                             psiElement().withText("")),
+                           psiElement().withParent(PsiErrorElement.class))
+        .withParent(PsiJavaCodeReferenceElement.class)
+        .withSuperParent(2, PsiTypeElement.class)
+        .withSuperParent(3, PsiClass.class),
       // like `call(Cls::methodRef.<caret>`
       psiElement().afterLeaf(psiElement(JavaTokenType.DOT).afterSibling(psiElement(PsiMethodCallExpression.class).withLastChild(
         psiElement(PsiExpressionList.class).withLastChild(psiElement(PsiErrorElement.class))))),

java/java-tests/testData/codeInsight/completion/normal/NoSuggestionsAfterDotAtClassLevel.java

@@ -0,0 +1,9 @@
+class Foo {
+  class A{}
+
+  public static void main(String[] args) {
+
+  }
+
+  .<caret>
+}

java/java-tests/testData/codeInsight/completion/normal/SuggestionsAfterDotAtClassLevel.java

@@ -0,0 +1,9 @@
+class Foo {
+  class A{}
+
+  public static void main(String[] args) {
+
+  }
+
+  Foo.<caret>
+}

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

@@ -3276,4 +3276,12 @@ public class NormalCompletionTest extends NormalCompletionTestCase {
       }
       """);
   }
+
+  public void testNoSuggestionsAfterDotAtClassLevel() { doAntiTest(); }
+
+  public void testSuggestionsAfterDotAtClassLevel() {
+    configureByTestName();
+    myFixture.completeBasic();
+    assertTrue(myFixture.getLookupElementStrings().contains("A"));
+  }
 }