restore that ClassInheritorsSearch returns unique results (IDEA-119628)

java/java-indexing-api/src/com/intellij/psi/search/searches/ClassInheritorsSearch.java

@@ -156,7 +156,7 @@ public class ClassInheritorsSearch extends ExtensibleQueryFactory<PsiClass, Clas
   }
 
   public static Query<PsiClass> search(@NotNull SearchParameters parameters) {
-    return INSTANCE.createQuery(parameters);
+    return INSTANCE.createUniqueResultsQuery(parameters);
   }
 
   public static Query<PsiClass> search(@NotNull final PsiClass aClass, @NotNull SearchScope scope, final boolean checkDeep, final boolean checkInheritance) {

java/java-tests/testData/psi/search/inheritors/multipleInheritance/Test.java

@@ -0,0 +1,3 @@
+interface I {}
+class A implements I {}
+class B extends A implements I{}

java/java-tests/testSrc/com/intellij/codeInsight/daemon/ImplementationsViewTest.java

@@ -116,7 +116,7 @@ public class ImplementationsViewTest extends LightCodeInsightFixtureTestCase {
     try {
       final String[] visibleFiles = component.getVisibleFiles();
       Assert.assertArrayEquals(Arrays.toString(visibleFiles),
-                               new String[]{"a.java (AFoo)", "a.java (AFoo1 in AFoo)", "a.java (AFoo3 in AFoo)", "a.java (AFoo2 in AFoo)"}, visibleFiles);
+                               new String[]{"a.java (AFoo)", "a.java (AFoo1 in AFoo)", "a.java (AFoo2 in AFoo)", "a.java (AFoo3 in AFoo)"}, visibleFiles);
     }
     finally {
       component.removeNotify();

java/java-tests/testSrc/com/intellij/psi/search/InheritorsTest.java

@@ -53,6 +53,10 @@ public class InheritorsTest extends PsiTestCase{
     doTest("x.Test", "", true, "x.Goo", "x.Zoo");
   }
 
+  public void testMultipleInheritance() throws Exception {
+    doTest("I", "", true, "A", "B");
+  }
+
   private void doTest(String className, String packageScopeName, final boolean deep, String... inheritorNames) throws Exception {
     final PsiClass aClass = myJavaFacade.findClass(className);
     assertNotNull(aClass);

platform/lang-impl/src/com/intellij/codeInsight/hint/ImplementationViewComponent.java

@@ -60,10 +60,8 @@ import java.awt.*;
 import java.awt.event.ActionEvent;
 import java.awt.event.ActionListener;
 import java.awt.event.KeyEvent;
-import java.util.ArrayList;
-import java.util.HashSet;
+import java.util.*;
 import java.util.List;
-import java.util.Set;
 
 public class ImplementationViewComponent extends JPanel {
   @NonNls private static final String TEXT_PAGE_KEY = "Text";
@@ -173,7 +171,7 @@ public class ImplementationViewComponent extends JPanel {
     toolbarPanel.add(myToolbar.getComponent(), gc);
 
     setPreferredSize(new Dimension(600, 400));
-    
+
     update(elements, new PairFunction<PsiElement[], List<FileDescriptor>, Boolean>() {
       @Override
       public Boolean fun(final PsiElement[] psiElements, final List<FileDescriptor> fileDescriptors) {
@@ -273,7 +271,7 @@ public class ImplementationViewComponent extends JPanel {
       @Override
       public Boolean fun(PsiElement[] psiElements, List<FileDescriptor> fileDescriptors) {
         if (psiElements.length == 0) return false;
-        
+
         final Project project = psiElements[0].getProject();
         myElements = psiElements;
 
@@ -302,7 +300,7 @@ public class ImplementationViewComponent extends JPanel {
         else {
           myFileChooser.setVisible(false);
           myCountLabel.setVisible(false);
-          
+
           VirtualFile file = psiFile.getVirtualFile();
           if (file != null) {
             myLabel.setIcon(getIconForFile(psiFile));
@@ -321,9 +319,9 @@ public class ImplementationViewComponent extends JPanel {
         return true;
       }
     });
-    
+
   }
-  
+
   private static void update(@NotNull PsiElement[] elements, @NotNull PairFunction<PsiElement[], List<FileDescriptor>, Boolean> fun) {
     List<PsiElement> candidates = new ArrayList<PsiElement>(elements.length);
     List<FileDescriptor> files = new ArrayList<FileDescriptor>(elements.length);
@@ -333,6 +331,15 @@ public class ImplementationViewComponent extends JPanel {
         names.add(((PsiNamedElement)element).getName());
       }
     }
+    Arrays.sort(elements, new Comparator<PsiElement>() {
+      @Override
+      public int compare(PsiElement e1, PsiElement e2) {
+        if (e1 instanceof PsiNamedElement && e2 instanceof PsiNamedElement) {
+          return Comparing.compare(((PsiNamedElement)e1).getName(), ((PsiNamedElement)e2).getName());
+        }
+        return e1.hashCode() - e2.hashCode();
+      }
+    });
     for (PsiElement element : elements) {
       PsiFile file = getContainingFile(element);
       if (file == null) continue;