diff --git a/Interop/Indexer/prebuilt/nativeInteropStubs/kotlin/clang/clang.kt b/Interop/Indexer/prebuilt/nativeInteropStubs/kotlin/clang/clang.kt
index 95d3e111507..5dabd5b5aa2 100644
--- a/Interop/Indexer/prebuilt/nativeInteropStubs/kotlin/clang/clang.kt
+++ b/Interop/Indexer/prebuilt/nativeInteropStubs/kotlin/clang/clang.kt
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-@file:Suppress("UNUSED_EXPRESSION")
+@file:Suppress("UNUSED_EXPRESSION", "UNUSED_VARIABLE")
 package clang
 
 import kotlinx.cinterop.*
diff --git a/Interop/Indexer/src/main/kotlin/org/jetbrains/kotlin/native/interop/indexer/Indexer.kt b/Interop/Indexer/src/main/kotlin/org/jetbrains/kotlin/native/interop/indexer/Indexer.kt
index f3d7ccf0645..9f05b1931e2 100644
--- a/Interop/Indexer/src/main/kotlin/org/jetbrains/kotlin/native/interop/indexer/Indexer.kt
+++ b/Interop/Indexer/src/main/kotlin/org/jetbrains/kotlin/native/interop/indexer/Indexer.kt
@@ -203,18 +203,17 @@ internal class NativeIndexImpl(val library: NativeLibrary) : NativeIndex() {
 
             CXCursorKind.CXCursor_UnionDecl -> return false
 
-            CXCursorKind.CXCursor_StructDecl -> memScoped {
-                val hasAttributes = memScope.alloc<CInt32Var>()
-                hasAttributes.value = 0
-                clang_visitChildren(structDefCursor, staticCFunction { cursor, parent, clientData ->
-                    if (clang_isAttribute(cursor.kind.value) != 0) {
-                        val hasAttributes = clientData!!.reinterpret<CInt32Var>().pointed
-                        hasAttributes.value = 1
+            CXCursorKind.CXCursor_StructDecl -> {
+                var hasAttributes = false
+
+                visitChildren(structDefCursor) { cursor, _ ->
+                    if (clang_isAttribute(cursor.kind) != 0) {
+                        hasAttributes = true
                     }
                     CXChildVisitResult.CXChildVisit_Continue
-                }, hasAttributes.ptr)
+                }
 
-                return hasAttributes.value == 0
+                return !hasAttributes
             }
 
             else -> throw IllegalArgumentException(defKind.toString())
@@ -332,6 +331,10 @@ internal class NativeIndexImpl(val library: NativeLibrary) : NativeIndex() {
             CXIdxEntity_Enum -> {
                 getEnumDefAt(cursor)
             }
+
+            else -> {
+                // Ignore declaration.
+            }
         }
     }
 
@@ -365,6 +368,7 @@ private fun indexDeclarations(library: NativeLibrary, nativeIndex: NativeIndexIm
                         importedASTFile.value = null
                         startedTranslationUnit.value = null
                         indexDeclaration.value = staticCFunction { clientData, info ->
+                            @Suppress("NAME_SHADOWING")
                             val nativeIndex = StableObjPtr.fromValue(clientData!!).get() as NativeIndexImpl
                             nativeIndex.indexDeclaration(info!!.pointed)
                         }
diff --git a/Interop/Indexer/src/main/kotlin/org/jetbrains/kotlin/native/interop/indexer/MacroConstants.kt b/Interop/Indexer/src/main/kotlin/org/jetbrains/kotlin/native/interop/indexer/MacroConstants.kt
index f425ef04155..a97d49d26b9 100644
--- a/Interop/Indexer/src/main/kotlin/org/jetbrains/kotlin/native/interop/indexer/MacroConstants.kt
+++ b/Interop/Indexer/src/main/kotlin/org/jetbrains/kotlin/native/interop/indexer/MacroConstants.kt
@@ -139,7 +139,7 @@ private fun processCodeSnippet(
     var longValue: Long? = null
     var doubleValue: Double? = null
 
-    val visitor: CursorVisitor = { cursor, parent ->
+    val visitor: CursorVisitor = { cursor, _ ->
         val kind = cursor.kind
         when {
             state == VisitorState.EXPECT_VARIABLE && kind == CXCursorKind.CXCursor_VarDecl -> {
@@ -216,7 +216,7 @@ private fun collectMacroConstantsNames(library: NativeLibrary): List<String> {
 
         val translationUnit = library.parse(index, options).ensureNoCompileErrors()
         try {
-            visitChildren(translationUnit) { cursor, parent ->
+            visitChildren(translationUnit) { cursor, _ ->
                 if (cursor.kind == CXCursorKind.CXCursor_MacroDefinition &&
                         library.includesDeclaration(cursor) &&
                         canMacroBeConstant(cursor))
diff --git a/Interop/Indexer/src/main/kotlin/org/jetbrains/kotlin/native/interop/indexer/Utils.kt b/Interop/Indexer/src/main/kotlin/org/jetbrains/kotlin/native/interop/indexer/Utils.kt
index d4ce394dbcc..cf4aeaa5d93 100644
--- a/Interop/Indexer/src/main/kotlin/org/jetbrains/kotlin/native/interop/indexer/Utils.kt
+++ b/Interop/Indexer/src/main/kotlin/org/jetbrains/kotlin/native/interop/indexer/Utils.kt
@@ -117,6 +117,7 @@ internal fun visitChildren(parent: CValue<CXCursor>, visitor: CursorVisitor) {
     val visitorPtr = StableObjPtr.create(visitor)
     val clientData = visitorPtr.value
     clang_visitChildren(parent, staticCFunction { cursor, parent, clientData ->
+        @Suppress("NAME_SHADOWING", "UNCHECKED_CAST")
         val visitor = StableObjPtr.fromValue(clientData!!).get() as CursorVisitor
         visitor(cursor.readValue(), parent.readValue())
     }, clientData)
diff --git a/Interop/Runtime/src/jvm/kotlin/kotlinx/cinterop/JvmCallbacks.kt b/Interop/Runtime/src/jvm/kotlin/kotlinx/cinterop/JvmCallbacks.kt
index 9f8332e5249..264c947dda5 100644
--- a/Interop/Runtime/src/jvm/kotlin/kotlinx/cinterop/JvmCallbacks.kt
+++ b/Interop/Runtime/src/jvm/kotlin/kotlinx/cinterop/JvmCallbacks.kt
@@ -233,9 +233,10 @@ private fun ffiCreateCif(returnType: ffi_type, paramTypes: List<ffi_type>): ffi_
     return interpretPointed(res)
 }
 
+@Suppress("UNUSED_PARAMETER")
 private fun ffiFunImpl0(ffiCif: Long, ret: Long, args: Long, userData: Any) {
-    ffiFunImpl(interpretPointed(ffiCif),
-            interpretCPointer(ret)!!,
+    @Suppress("UNCHECKED_CAST")
+    ffiFunImpl(interpretCPointer(ret)!!,
             interpretCPointer(args)!!,
             userData as UserData)
 }
@@ -246,8 +247,7 @@ private fun ffiFunImpl0(ffiCif: Long, ret: Long, args: Long, userData: Any) {
  * @param ret pointer to memory to be filled with return value of the invoked native function
  * @param args pointer to array of pointers to arguments passed to the invoked native function
  */
-private fun ffiFunImpl(ffiCif: ffi_cif, ret: COpaquePointer, args: CArrayPointer<COpaquePointerVar>,
-                       userData: UserData) {
+private fun ffiFunImpl(ret: COpaquePointer, args: CArrayPointer<COpaquePointerVar>, userData: UserData) {
 
     userData.invoke(ret, args)
 }
diff --git a/Interop/Runtime/src/jvm/kotlin/kotlinx/cinterop/JvmTypes.kt b/Interop/Runtime/src/jvm/kotlin/kotlinx/cinterop/JvmTypes.kt
index 8863b72910e..d5c143c2376 100644
--- a/Interop/Runtime/src/jvm/kotlin/kotlinx/cinterop/JvmTypes.kt
+++ b/Interop/Runtime/src/jvm/kotlin/kotlinx/cinterop/JvmTypes.kt
@@ -16,8 +16,8 @@
 
 package kotlinx.cinterop
 
-import kotlin.reflect.companionObjectInstance
-import kotlin.reflect.primaryConstructor
+import kotlin.reflect.full.companionObjectInstance
+import kotlin.reflect.full.primaryConstructor
 
 typealias NativePtr = Long
 val nativeNullPtr: NativePtr = 0L
@@ -40,6 +40,7 @@ inline fun <reified T : NativePointed> interpretNullablePointed(ptr: NativePtr):
         if (primaryConstructor == null) {
             throw IllegalArgumentException("${kClass.simpleName} doesn't have a constructor")
         }
+        @Suppress("UNCHECKED_CAST")
         return (primaryConstructor as (NativePtr) -> T)(ptr)
     }
 }
diff --git a/Interop/Runtime/src/main/kotlin/kotlinx/cinterop/Types.kt b/Interop/Runtime/src/main/kotlin/kotlinx/cinterop/Types.kt
index 30be39f268a..5e070f1f89f 100644
--- a/Interop/Runtime/src/main/kotlin/kotlinx/cinterop/Types.kt
+++ b/Interop/Runtime/src/main/kotlin/kotlinx/cinterop/Types.kt
@@ -237,26 +237,32 @@ abstract class CEnumVar : CPrimitiveVar()
 // generics below are used for typedef support
 // these classes are not supposed to be used directly, instead the typealiases are provided.
 
+@Suppress("FINAL_UPPER_BOUND")
 class CInt8VarWithValueMappedTo<T : Byte>(override val rawPtr: NativePtr) : CPrimitiveVar() {
     companion object : Type(1)
 }
 
+@Suppress("FINAL_UPPER_BOUND")
 class CInt16VarWithValueMappedTo<T : Short>(override val rawPtr: NativePtr) : CPrimitiveVar() {
     companion object : Type(2)
 }
 
+@Suppress("FINAL_UPPER_BOUND")
 class CInt32VarWithValueMappedTo<T : Int>(override val rawPtr: NativePtr) : CPrimitiveVar() {
     companion object : Type(4)
 }
 
+@Suppress("FINAL_UPPER_BOUND")
 class CInt64VarWithValueMappedTo<T : Long>(override val rawPtr: NativePtr) : CPrimitiveVar() {
     companion object : Type(8)
 }
 
+@Suppress("FINAL_UPPER_BOUND")
 class CFloat32VarWithValueMappedTo<T : Float>(override val rawPtr: NativePtr) : CPrimitiveVar() {
     companion object : Type(4)
 }
 
+@Suppress("FINAL_UPPER_BOUND")
 class CFloat64VarWithValueMappedTo<T : Double>(override val rawPtr: NativePtr) : CPrimitiveVar() {
     companion object : Type(8)
 }
@@ -268,28 +274,34 @@ typealias CInt64Var = CInt64VarWithValueMappedTo<Long>
 typealias CFloat32Var = CFloat32VarWithValueMappedTo<Float>
 typealias CFloat64Var = CFloat64VarWithValueMappedTo<Double>
 
+@Suppress("FINAL_UPPER_BOUND", "UNCHECKED_CAST")
 var <T : Byte> CInt8VarWithValueMappedTo<T>.value: T
     get() = nativeMemUtils.getByte(this) as T
     set(value) = nativeMemUtils.putByte(this, value)
 
+@Suppress("FINAL_UPPER_BOUND", "UNCHECKED_CAST")
 var <T : Short> CInt16VarWithValueMappedTo<T>.value: T
     get() = nativeMemUtils.getShort(this) as T
     set(value) = nativeMemUtils.putShort(this, value)
 
+@Suppress("FINAL_UPPER_BOUND", "UNCHECKED_CAST")
 var <T : Int> CInt32VarWithValueMappedTo<T>.value: T
     get() = nativeMemUtils.getInt(this) as T
     set(value) = nativeMemUtils.putInt(this, value)
 
+@Suppress("FINAL_UPPER_BOUND", "UNCHECKED_CAST")
 var <T : Long> CInt64VarWithValueMappedTo<T>.value: T
     get() = nativeMemUtils.getLong(this) as T
     set(value) = nativeMemUtils.putLong(this, value)
 
 // TODO: ensure native floats have the appropriate binary representation
 
+@Suppress("FINAL_UPPER_BOUND", "UNCHECKED_CAST")
 var <T : Float> CFloat32VarWithValueMappedTo<T>.value: T
     get() = nativeMemUtils.getFloat(this) as T
     set(value) = nativeMemUtils.putFloat(this, value)
 
+@Suppress("FINAL_UPPER_BOUND", "UNCHECKED_CAST")
 var <T : Double> CFloat64VarWithValueMappedTo<T>.value: T
     get() = nativeMemUtils.getDouble(this) as T
     set(value) = nativeMemUtils.putDouble(this, value)
@@ -307,6 +319,7 @@ typealias CPointerVar<T> = CPointerVarWithValueMappedTo<CPointer<T>>
 /**
  * The value of this variable.
  */
+@Suppress("UNCHECKED_CAST")
 inline var <P : CPointer<*>> CPointerVarWithValueMappedTo<P>.value: P?
     get() = interpretCPointer<CPointed>(nativeMemUtils.getNativePtr(this)) as P?
     set(value) = nativeMemUtils.putNativePtr(this, value.rawValue)
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 33ced7b9617..f296a95bef0 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
@@ -1192,7 +1192,7 @@ class StubGenerator(
      * Produces to [out] the contents of file with Kotlin bindings.
      */
     fun generateKotlinFile() {
-        out("@file:Suppress(\"UNUSED_EXPRESSION\")")
+        out("@file:Suppress(\"UNUSED_EXPRESSION\", \"UNUSED_VARIABLE\")")
         if (pkgName != "") {
             out("package $pkgName")
             out("")
diff --git a/Interop/StubGenerator/src/main/kotlin/org/jetbrains/kotlin/native/interop/gen/jvm/main.kt b/Interop/StubGenerator/src/main/kotlin/org/jetbrains/kotlin/native/interop/gen/jvm/main.kt
index 526e523f20f..4d72a7a3825 100644
--- a/Interop/StubGenerator/src/main/kotlin/org/jetbrains/kotlin/native/interop/gen/jvm/main.kt
+++ b/Interop/StubGenerator/src/main/kotlin/org/jetbrains/kotlin/native/interop/gen/jvm/main.kt
@@ -136,6 +136,7 @@ private fun runCmd(command: Array<String>, workDir: File, verbose: Boolean = fal
 private fun maybeExecuteHelper(dependenciesRoot: String, properties: Properties, dependencies: List<String>) {
     try {
         val kClass = Class.forName("org.jetbrains.kotlin.konan.Helper0").kotlin
+        @Suppress("UNCHECKED_CAST")
         val ctor = kClass.constructors.single() as KFunction<Runnable>
         val result = ctor.call(dependenciesRoot, properties, dependencies)
         result.run()
diff --git a/backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/common/IrValidator.kt b/backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/common/IrValidator.kt
index 05cdd6a0793..3c50396a18b 100644
--- a/backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/common/IrValidator.kt
+++ b/backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/common/IrValidator.kt
@@ -42,7 +42,10 @@ fun validateIrModule(context: BackendContext, irModule: IrModuleFragment) {
     irModule.acceptVoid(visitor)
 
     // TODO: investigate and re-enable
-    return
+    val ENABLE_EXTENDED_VALIDATION = false
+    if (!ENABLE_EXTENDED_VALIDATION) {
+        return
+    }
 
     val moduleDeclarations = visitor.foundDeclarations
 
diff --git a/backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/lower/Autoboxing.kt b/backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/lower/Autoboxing.kt
index 73b1f933246..42496808c23 100644
--- a/backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/lower/Autoboxing.kt
+++ b/backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/lower/Autoboxing.kt
@@ -188,6 +188,7 @@ private class AutoboxingTransformer(val context: Context) : AbstractValueUsageTr
     /**
      * Casts this expression to `type` without changing its representation in generated code.
      */
+    @Suppress("UNUSED_PARAMETER")
     private fun IrExpression.uncheckedCast(type: KotlinType): IrExpression {
         // TODO: apply some cast if types are incompatible; not required currently.
         return this
diff --git a/backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/lower/InteropLowering.kt b/backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/lower/InteropLowering.kt
index cb6366b431d..b2ab3fe9837 100644
--- a/backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/lower/InteropLowering.kt
+++ b/backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/lower/InteropLowering.kt
@@ -106,6 +106,7 @@ private class InteropTransformer(val context: Context, val irFile: IrFile) : IrB
         return alignOf(typeObject)
     }
 
+    @Suppress("UNUSED_PARAMETER")
     private fun IrBuilderWithScope.interpretPointed(expression: IrCall, type: KotlinType): IrExpression =
             irCall(interop.interpretNullablePointed).apply {
                 putValueArgument(0, expression)
@@ -149,6 +150,7 @@ private class InteropTransformer(val context: Context, val irFile: IrFile) : IrB
         }
     }
 
+    @Suppress("UNUSED_PARAMETER")
     private fun IrBuilderWithScope.nativePointedToCPointer(
             expression: IrExpression, pointeeType: KotlinType
     ): IrExpression = irCall(interop.interpretCPointer).apply {