diff --git a/libraries/stdlib/src/generated/_SpecialJVM.kt b/libraries/stdlib/src/generated/_SpecialJVM.kt
index a48abe04611..21b31cbba84 100644
--- a/libraries/stdlib/src/generated/_SpecialJVM.kt
+++ b/libraries/stdlib/src/generated/_SpecialJVM.kt
@@ -203,8 +203,8 @@ public fun ShortArray.binarySearch(element: Short, fromIndex: Int = 0, toIndex:
 /**
  * Returns new array which is a copy of the original array.
  */
-public fun <T> Array<out T>.copyOf(): Array<out T> {
-    return Arrays.copyOf(this, size())
+public fun <T, A: Array<out T>> A.copyOf(): A {
+    return Arrays.copyOf(this, size()) as A
 }
 
 /**
@@ -263,14 +263,6 @@ public fun ShortArray.copyOf(): ShortArray {
     return Arrays.copyOf(this, size())
 }
 
-/**
- * Returns new array which is a copy of the original array.
- */
-platformName("mutableCopyOf")
-public fun <T> Array<T>.copyOf(): Array<T> {
-    return Arrays.copyOf(this, size())
-}
-
 /**
  * Returns new array which is a copy of the original array.
  */
@@ -345,8 +337,8 @@ public fun <T> Array<T>.copyOf(newSize: Int): Array<T?> {
 /**
  * Returns new array which is a copy of range of original array.
  */
-public fun <T> Array<out T>.copyOfRange(fromIndex: Int, toIndex: Int): Array<out T> {
-    return Arrays.copyOfRange(this, fromIndex, toIndex)
+public fun <T, A: Array<out T>> A.copyOfRange(fromIndex: Int, toIndex: Int): A {
+    return Arrays.copyOfRange(this, fromIndex, toIndex) as A
 }
 
 /**
@@ -405,14 +397,6 @@ public fun ShortArray.copyOfRange(fromIndex: Int, toIndex: Int): ShortArray {
     return Arrays.copyOfRange(this, fromIndex, toIndex)
 }
 
-/**
- * Returns new array which is a copy of range of original array.
- */
-platformName("mutableCopyOfRange")
-public fun <T> Array<T>.copyOfRange(fromIndex: Int, toIndex: Int): Array<T> {
-    return Arrays.copyOfRange(this, fromIndex, toIndex)
-}
-
 /**
  * Fills original array with the provided value.
  */
diff --git a/libraries/tools/kotlin-stdlib-gen/src/templates/Engine.kt b/libraries/tools/kotlin-stdlib-gen/src/templates/Engine.kt
index 6607f773a8a..a1a0135ac5b 100644
--- a/libraries/tools/kotlin-stdlib-gen/src/templates/Engine.kt
+++ b/libraries/tools/kotlin-stdlib-gen/src/templates/Engine.kt
@@ -16,6 +16,7 @@ enum class Family {
     ArraysOfObjects,
     ArraysOfPrimitives,
     InvariantArraysOfObjects,
+    ArraysOfObjectsSubtype,
     Strings,
     Ranges,
     RangesOfPrimitives,
@@ -167,7 +168,7 @@ class GenericFunction(val signature: String, val keyword: String = "fun") : Comp
 
     fun build(vararg families: Family = Family.values()): String {
         val builder = StringBuilder()
-        for (family in families.sortBy { it.name() }) {
+        for (family in families.sortedBy { it.name() }) {
             if (buildFamilies.contains(family))
                 build(builder, family)
         }
@@ -177,7 +178,7 @@ class GenericFunction(val signature: String, val keyword: String = "fun") : Comp
     fun build(builder: StringBuilder, f: Family) {
         val onlyPrimitives = buildFamilyPrimitives[f]
         if (f.isPrimitiveSpecialization || onlyPrimitives != null) {
-            for (primitive in (onlyPrimitives ?: buildPrimitives).sortBy { it.name() })
+            for (primitive in (onlyPrimitives ?: buildPrimitives).sortedBy { it.name() })
                 build(builder, f, primitive)
         } else {
             build(builder, f, null)
@@ -262,6 +263,7 @@ class GenericFunction(val signature: String, val keyword: String = "fun") : Comp
             Sets -> "Set<$isAsteriskOrT>"
             Sequences -> "Sequence<$isAsteriskOrT>"
             InvariantArraysOfObjects -> "Array<T>"
+            ArraysOfObjectsSubtype -> "A"
             ArraysOfObjects -> "Array<${isAsteriskOrT.replace("T", "out T")}>"
             Strings -> "String"
             Ranges -> "Range<$isAsteriskOrT>"
@@ -275,8 +277,19 @@ class GenericFunction(val signature: String, val keyword: String = "fun") : Comp
         fun String.renderType(): String = renderType(this, receiver)
 
         fun effectiveTypeParams(): List<String> {
+            fun getGenericTypeParameters(genericType: String) =
+                genericType
+                    .dropWhile { it != '<' }
+                    .drop(1)
+                    .takeWhile { it != '>' }
+                    .split(",")
+                    .map { it.removePrefix("out").removePrefix("in").trim() }
+
             // TODO: Model for type parameter
             val types = ArrayList(typeParams)
+            if (f == ArraysOfObjectsSubtype) {
+                types.add("A: Array<out T>")
+            }
             if (f == Generic) {
                 // ensure type parameter T, if it's not added to typeParams before
                 if (!types.any { it == "T" || it.startsWith("T:")}) {
@@ -285,9 +298,8 @@ class GenericFunction(val signature: String, val keyword: String = "fun") : Comp
                 return types
             }
             else if (primitive == null && f != Strings) {
-                val implicitTypeParameters = receiver.dropWhile { it != '<' }.drop(1).takeWhile { it != '>' }.split(",")
-                        .map { it.removePrefix("out").removePrefix("in").trim() }
-                for (implicit in implicitTypeParameters.reverse()) {
+                val implicitTypeParameters = getGenericTypeParameters(receiver) + types.flatMap { getGenericTypeParameters(it) }
+                for (implicit in implicitTypeParameters.reversed()) {
                     if (implicit != "*" && !types.any { it.startsWith(implicit) || it.startsWith("reified " + implicit) }) {
                         types.add(0, implicit)
                     }
@@ -295,7 +307,8 @@ class GenericFunction(val signature: String, val keyword: String = "fun") : Comp
 
                 return types
             } else {
-                // primitive type arrays should drop constraints
+                // remove T as parameter
+                // TODO: Substitute primitive or String instead of T in other parameters from effective types not from original typeParams
                 return typeParams.filter { !it.startsWith("T") }
             }
         }
diff --git a/libraries/tools/kotlin-stdlib-gen/src/templates/SpecialJVM.kt b/libraries/tools/kotlin-stdlib-gen/src/templates/SpecialJVM.kt
index ceec51f09a2..826ba0af2b4 100644
--- a/libraries/tools/kotlin-stdlib-gen/src/templates/SpecialJVM.kt
+++ b/libraries/tools/kotlin-stdlib-gen/src/templates/SpecialJVM.kt
@@ -51,23 +51,27 @@ fun specialJVM(): List<GenericFunction> {
 
 
     templates add f("copyOfRange(fromIndex: Int, toIndex: Int)") {
-        only(ArraysOfObjects, InvariantArraysOfObjects, ArraysOfPrimitives)
+        only(ArraysOfObjectsSubtype, ArraysOfPrimitives)
         doc { "Returns new array which is a copy of range of original array." }
         returns("SELF")
-        annotations(InvariantArraysOfObjects) { """platformName("mutableCopyOfRange")"""}
         body {
             "return Arrays.copyOfRange(this, fromIndex, toIndex)"
         }
+        body(ArraysOfObjectsSubtype) {
+            "return Arrays.copyOfRange(this, fromIndex, toIndex) as A"
+        }
     }
 
     templates add f("copyOf()") {
-        only(ArraysOfObjects, InvariantArraysOfObjects, ArraysOfPrimitives)
+        only(ArraysOfObjectsSubtype, ArraysOfPrimitives)
         doc { "Returns new array which is a copy of the original array." }
         returns("SELF")
-        annotations(InvariantArraysOfObjects) { """platformName("mutableCopyOf")"""}
         body {
             "return Arrays.copyOf(this, size())"
         }
+        body(ArraysOfObjectsSubtype) {
+            "return Arrays.copyOf(this, size()) as A"
+        }
     }
 
     // This overload can cause nulls if array size is expanding, hence different return overload