Smart completion of inheritors: correct filtering of duplicates

idea/testData/completion/smartMultiFile/InheritorsAndMultipleExpectedTypes/Declarations.kt

@@ -0,0 +1,16 @@
+class X
+class Y
+
+trait T1
+trait T2<T>
+trait T3<T>
+
+class C1 : T1
+class C2<T> : T2<T>, T3<T>
+class C3 : T1, T2<X>
+
+fun foo(p: T1){}
+fun foo(p: T2<X>){}
+fun foo(p: T3<Y>){}
+
+// ALLOW_AST_ACCESS

idea/testData/completion/smartMultiFile/InheritorsAndMultipleExpectedTypes/InheritorsAndMultipleExpectedTypes.kt

@@ -0,0 +1,12 @@
+fun bar() {
+    foo(<caret>)
+}
+
+// EXIST: { lookupString: "object", itemText: "object: T1{...}" }
+// EXIST: { lookupString: "object", itemText: "object: T2<X>{...}" }
+// EXIST: { lookupString: "object", itemText: "object: T3<Y>{...}" }
+// EXIST: { lookupString: "C1", itemText: "C1" }
+// EXIST: { lookupString: "C2", itemText: "C2<X>" }
+// EXIST: { lookupString: "C2", itemText: "C2<Y>" }
+// EXIST: { lookupString: "C3", itemText: "C3" }
+// NUMBER: 7