IDEA-178535 Duplicate class suggestions in cast

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

@@ -125,7 +125,7 @@ class SmartCastProvider extends CompletionProvider<CompletionParameters> {
     if (info.getKind() == ExpectedTypeInfo.TYPE_OR_SUPERTYPE) {
       InheritanceUtil.processSupers(infoClass, true, superClass -> {
         if (!CommonClassNames.JAVA_LANG_OBJECT.equals(superClass.getQualifiedName())) {
-          result.consume(JavaPsiFacade.getElementFactory(superClass.getProject()).createType(superClass));
+          result.consume(JavaPsiFacade.getElementFactory(superClass.getProject()).createType(CompletionUtil.getOriginalOrSelf(superClass)));
         }
         return true;
       });

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

@@ -0,0 +1,11 @@
+class X {
+  void foo(Object o){
+    if (o instanceof Foo) {
+      ((Foo<caret>) o).bar();
+    }
+  }
+
+  class Foo {
+    void bar() {}
+  }
+}

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

@@ -1837,4 +1837,9 @@ class Bar {{
     assert LookupElementPresentation.renderElement(item).tailText.contains('local class')
   }
 
+  void testNoDuplicateInCast() {
+    configure()
+    assert myFixture.lookupElementStrings == null
+  }
+
 }