diff --git a/Interop/StubGenerator/build.gradle b/Interop/StubGenerator/build.gradle
index c03109ffe79..b73417847a8 100644
--- a/Interop/StubGenerator/build.gradle
+++ b/Interop/StubGenerator/build.gradle
@@ -36,3 +36,9 @@ dependencies {
     compile project(':Interop:Indexer')
     compile "org.jetbrains.kotlin:kotlin-native-shared:$konanVersion"
 }
+
+compileKotlin {
+    kotlinOptions {
+        freeCompilerArgs = ['-Xuse-experimental=kotlin.ExperimentalUnsignedTypes']
+    }
+}
diff --git a/Interop/StubGenerator/src/main/kotlin/org/jetbrains/kotlin/native/interop/gen/jvm/StubGenerator.kt b/Interop/StubGenerator/src/main/kotlin/org/jetbrains/kotlin/native/interop/gen/jvm/StubGenerator.kt
index 6316d0ad63e..07d2649dad3 100644
--- a/Interop/StubGenerator/src/main/kotlin/org/jetbrains/kotlin/native/interop/gen/jvm/StubGenerator.kt
+++ b/Interop/StubGenerator/src/main/kotlin/org/jetbrains/kotlin/native/interop/gen/jvm/StubGenerator.kt
@@ -732,32 +732,31 @@ class StubGenerator(
     }
 
     private fun integerLiteral(size: Int, isSigned: Boolean, value: Long): String? {
-        if (!isSigned) {
-            val signedLiteral = integerLiteral(size, true, value)
-            val converter = when (size) {
-                1 -> "toUByte"
-                2 -> "toUShort"
-                4 -> "toUInt"
-                8 -> "toULong"
+        return if (isSigned) {
+            if (value == Long.MIN_VALUE) {
+                return "${value + 1} - 1" // Workaround for "The value is out of range" compile error.
+            }
+
+            val narrowedValue: Number = when (size) {
+                1 -> value.toByte()
+                2 -> value.toShort()
+                4 -> value.toInt()
+                8 -> value
                 else -> return null
             }
 
-            return "($signedLiteral).$converter()"
-        }
+            narrowedValue.toString()
+        } else {
+            val narrowedValue: Any = when (size) {
+                1 -> value.toUByte()
+                2 -> value.toUShort()
+                4 -> value.toUInt()
+                8 -> value.toULong()
+                else -> return null
+            }
 
-        if (value == Long.MIN_VALUE) {
-            return "${value + 1} - 1" // Workaround for "The value is out of range" compile error.
+            "${narrowedValue}u"
         }
-
-        val narrowedValue: Number = when (size) {
-            1 -> value.toByte()
-            2 -> value.toShort()
-            4 -> value.toInt()
-            8 -> value
-            else -> return null
-        }
-
-        return narrowedValue.toString()
     }
 
     private fun floatingLiteral(type: Type, value: Double): String? {
@@ -777,37 +776,41 @@ class StubGenerator(
         }
     }
 
+    private fun topLevelValWithGetter(name: String, type: KotlinType, expressionBody: String): String =
+            "val ${name.asSimpleName()}: ${type.render(kotlinFile)} get() = $expressionBody"
+
+    private fun topLevelConstVal(name: String, type: KotlinType, initializer: String): String =
+            "const val ${name.asSimpleName()}: ${type.render(kotlinFile)} = $initializer"
+
     private fun generateConstant(constant: ConstantDef) {
-        val literal = when (constant) {
-            is IntegerConstantDef -> integerLiteral(constant.type, constant.value) ?: return
-            is FloatingConstantDef -> floatingLiteral(constant.type, constant.value) ?: return
-            is StringConstantDef -> constant.value.quoteAsKotlinLiteral()
-            else -> {
-                // Not supported yet, ignore:
-                return
+        val kotlinName = constant.name
+        val declaration = when (constant) {
+            is IntegerConstantDef -> {
+                val literal = integerLiteral(constant.type, constant.value) ?: return
+                val kotlinType = mirror(constant.type).argType
+                when (platform) {
+                    KotlinPlatform.NATIVE -> topLevelConstVal(kotlinName, kotlinType, literal)
+                    // No reason to make it const val with backing field on Kotlin/JVM yet:
+                    KotlinPlatform.JVM -> topLevelValWithGetter(kotlinName, kotlinType, literal)
+                }
             }
+            is FloatingConstantDef -> {
+                val literal = floatingLiteral(constant.type, constant.value) ?: return
+                val kotlinType = mirror(constant.type).argType
+                topLevelValWithGetter(kotlinName, kotlinType, literal)
+            }
+            is StringConstantDef -> {
+                val literal = constant.value.quoteAsKotlinLiteral()
+                val kotlinType = KotlinTypes.string
+                topLevelValWithGetter(kotlinName, kotlinType, literal)
+            }
+            else -> return
         }
 
-        val kotlinType = when (constant) {
-            is IntegerConstantDef,
-            is FloatingConstantDef -> mirror(constant.type).argType
+        out(declaration)
 
-            is StringConstantDef -> KotlinTypes.string
-
-            else -> {
-                // Not supported yet, ignore:
-                return
-            }
-        }.render(kotlinFile)
-
-        // TODO: improve value rendering.
-
-        // TODO: consider using `const` modifier.
-        // It is not currently possible for floating literals.
-        // Also it provokes constant propagation which can reduce binary compatibility
-        // when replacing interop stubs without recompiling the application.
-
-        out("val ${constant.name.asSimpleName()}: $kotlinType get() = $literal")
+        // TODO: consider using `const` modifier in all cases.
+        // Note: It is not currently possible for floating literals.
     }
 
     private fun generateStubs(): List<KotlinStub> {
diff --git a/extracted/konan.serializer/src/org/jetbrains/kotlin/descriptors/konan/KonanModuleOrigin.kt b/extracted/konan.serializer/src/org/jetbrains/kotlin/descriptors/konan/KonanModuleOrigin.kt
index 8288183842f..85b6c3b6ee0 100644
--- a/extracted/konan.serializer/src/org/jetbrains/kotlin/descriptors/konan/KonanModuleOrigin.kt
+++ b/extracted/konan.serializer/src/org/jetbrains/kotlin/descriptors/konan/KonanModuleOrigin.kt
@@ -2,6 +2,7 @@ package org.jetbrains.kotlin.descriptors.konan
 
 import org.jetbrains.kotlin.descriptors.ModuleDescriptor
 import org.jetbrains.kotlin.konan.library.KonanLibrary
+import org.jetbrains.kotlin.konan.library.isInterop
 
 sealed class KonanModuleOrigin {
 
@@ -18,4 +19,9 @@ object CurrentKonanModuleOrigin: CompiledKonanModuleOrigin()
 
 object SyntheticModulesOrigin : KonanModuleOrigin()
 
+internal fun KonanModuleOrigin.isInteropLibrary(): Boolean = when (this) {
+    is DeserializedKonanModuleOrigin -> this.library.isInterop
+    CurrentKonanModuleOrigin, SyntheticModulesOrigin -> false
+}
+
 val ModuleDescriptor.konanModuleOrigin get() = this.getCapability(KonanModuleOrigin.CAPABILITY)!!
diff --git a/extracted/konan.serializer/src/org/jetbrains/kotlin/descriptors/konan/impl/KonanModuleDescriptorFactoryImpl.kt b/extracted/konan.serializer/src/org/jetbrains/kotlin/descriptors/konan/impl/KonanModuleDescriptorFactoryImpl.kt
index 75c6d3a5532..b62b3236751 100644
--- a/extracted/konan.serializer/src/org/jetbrains/kotlin/descriptors/konan/impl/KonanModuleDescriptorFactoryImpl.kt
+++ b/extracted/konan.serializer/src/org/jetbrains/kotlin/descriptors/konan/impl/KonanModuleDescriptorFactoryImpl.kt
@@ -6,7 +6,9 @@ import org.jetbrains.kotlin.descriptors.ModuleDescriptor
 import org.jetbrains.kotlin.descriptors.impl.ModuleDescriptorImpl
 import org.jetbrains.kotlin.descriptors.konan.KonanModuleDescriptorFactory
 import org.jetbrains.kotlin.descriptors.konan.KonanModuleOrigin
+import org.jetbrains.kotlin.descriptors.konan.isInteropLibrary
 import org.jetbrains.kotlin.name.Name
+import org.jetbrains.kotlin.resolve.ImplicitIntegerCoercion
 import org.jetbrains.kotlin.storage.StorageManager
 
 internal object KonanModuleDescriptorFactoryImpl: KonanModuleDescriptorFactory {
@@ -21,7 +23,10 @@ internal object KonanModuleDescriptorFactoryImpl: KonanModuleDescriptorFactory {
             name,
             storageManager,
             builtIns,
-            capabilities = customCapabilities + mapOf(KonanModuleOrigin.CAPABILITY to origin))
+            capabilities = customCapabilities + mapOf(
+                    KonanModuleOrigin.CAPABILITY to origin,
+                    ImplicitIntegerCoercion.MODULE_CAPABILITY to origin.isInteropLibrary()
+            ))
 
     override fun createDescriptorAndNewBuiltIns(
             name: Name,