Some tests for override action has been added.

idea/testData/codeInsight/overrideImplement/complexMultiOverride.kt.after

@@ -0,0 +1,16 @@
+open class Base<A, B, C>() {
+    open val method : (A?) -> A = { it!! }
+    open fun foo(value : B) : B = value
+    open fun bar(value : () -> C) : (String) -> C = { value() }
+}
+
+class C : Base<String, C, Unit>() {
+
+    override fun bar(value : () -> Unit) : (String) -> Unit {
+        return super<Base>.bar(value)
+    }
+    override fun foo(value : C) : C {
+        return super<Base>.foo(value)
+    }
+    override val method : (String?) -> String = ?
+}