diff --git a/backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/cgen/CBridgeGen.kt b/backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/cgen/CBridgeGen.kt
index 8f46c4bad8b..8ae7e7daad4 100644
--- a/backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/cgen/CBridgeGen.kt
+++ b/backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/cgen/CBridgeGen.kt
@@ -114,7 +114,7 @@ internal fun KotlinStubs.generateCCall(expression: IrCall, builder: IrBuilderWit
 
     val callBuilder = KotlinToCCallBuilder(builder, this, isObjCMethod = false)
 
-    val callee = expression.symbol.owner as IrSimpleFunction
+    val callee = expression.symbol.owner
 
     // TODO: consider computing all arguments before converting.
 
diff --git a/backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/lower/BridgesBuilding.kt b/backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/lower/BridgesBuilding.kt
index a9c67bf83b5..ede5e103ab2 100644
--- a/backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/lower/BridgesBuilding.kt
+++ b/backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/lower/BridgesBuilding.kt
@@ -110,7 +110,7 @@ internal class WorkersBridgesBuilding(val context: Context) : DeclarationContain
                         startOffset  = job.startOffset,
                         endOffset    = job.endOffset,
                         overriddenFunction = overriddenJobDescriptor,
-                        targetSymbol = job.symbol)
+                        targetSymbol = jobFunction.symbol)
                 bridges += bridge
                 expression.putValueArgument(3, IrFunctionReferenceImpl(
                         startOffset   = job.startOffset,
@@ -218,7 +218,7 @@ private fun IrBlockBodyBuilder.buildTypeSafeBarrier(function: IrFunction,
 }
 
 private fun Context.buildBridge(startOffset: Int, endOffset: Int,
-                                overriddenFunction: OverriddenFunctionInfo, targetSymbol: IrFunctionSymbol,
+                                overriddenFunction: OverriddenFunctionInfo, targetSymbol: IrSimpleFunctionSymbol,
                                 superQualifierSymbol: IrClassSymbol? = null): IrFunction {
 
     val bridge = specialDeclarationsFactory.getBridge(overriddenFunction)
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 44eb06f7a94..015e6d0093a 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
@@ -715,7 +715,7 @@ private class InteropLoweringPart1(val context: Context) : BaseInteropIrTransfor
 
             return builder.at(expression).run {
                 val classPtr = getRawPtr(expression.extensionReceiver!!)
-                callAllocAndInit(classPtr, initMethodInfo, arguments, expression, callee as IrSimpleFunction)
+                callAllocAndInit(classPtr, initMethodInfo, arguments, expression, callee)
             }
         }
 
@@ -753,7 +753,7 @@ private class InteropLoweringPart1(val context: Context) : BaseInteropIrTransfor
                         receiver = expression.dispatchReceiver ?: expression.extensionReceiver!!,
                         arguments = arguments,
                         call = expression,
-                        method = callee as IrSimpleFunction
+                        method = callee
                 )
             }
         }
diff --git a/backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/optimizations/DFGBuilder.kt b/backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/optimizations/DFGBuilder.kt
index d1deb8251f5..b4cb1633fef 100644
--- a/backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/optimizations/DFGBuilder.kt
+++ b/backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/optimizations/DFGBuilder.kt
@@ -23,6 +23,7 @@ import org.jetbrains.kotlin.ir.declarations.lazy.IrLazyClass
 import org.jetbrains.kotlin.ir.expressions.*
 import org.jetbrains.kotlin.ir.expressions.impl.*
 import org.jetbrains.kotlin.ir.symbols.IrClassSymbol
+import org.jetbrains.kotlin.ir.symbols.IrSimpleFunctionSymbol
 import org.jetbrains.kotlin.ir.symbols.IrTypeParameterSymbol
 import org.jetbrains.kotlin.ir.types.*
 import org.jetbrains.kotlin.ir.util.*
@@ -338,7 +339,7 @@ internal class ModuleDFGBuilder(val context: Context, val irModule: IrModuleFrag
                         ?: error("A function reference expected")
                 val jobInvocation = IrCallImpl(expression.startOffset, expression.endOffset,
                         jobFunctionReference.symbol.owner.returnType,
-                        jobFunctionReference.symbol)
+                        jobFunctionReference.symbol as IrSimpleFunctionSymbol)
                 jobInvocation.putValueArgument(0, producerInvocation)
 
                 expressions += jobInvocation
@@ -665,7 +666,6 @@ internal class ModuleDFGBuilder(val context: Context, val irModule: IrModuleFrag
                                     if (callee is IrConstructor) {
                                         error("Constructor call should be done with IrConstructorCall")
                                     } else {
-                                        callee as IrSimpleFunction
                                         if (callee.isOverridable && value.superQualifierSymbol == null) {
                                             val owner = callee.parentAsClass
                                             val actualReceiverType = value.dispatchReceiver!!.type
diff --git a/backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/optimizations/Devirtualization.kt b/backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/optimizations/Devirtualization.kt
index 0e545e82b35..a883a07df73 100644
--- a/backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/optimizations/Devirtualization.kt
+++ b/backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/optimizations/Devirtualization.kt
@@ -1402,7 +1402,7 @@ internal object Devirtualization {
                                                    actualType: IrType,
                                                    devirtualizedCallee: DevirtualizedCallee,
                                                    arguments: List<IrExpression>): IrCall {
-            val actualCallee = devirtualizedCallee.callee.irFunction!!
+            val actualCallee = devirtualizedCallee.callee.irFunction as IrSimpleFunction
             val call = IrCallImpl(
                     callSite.startOffset, callSite.endOffset,
                     actualType,
diff --git a/backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/ir/util/IrUtils2.kt b/backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/ir/util/IrUtils2.kt
index 08050038c52..bc63efc150f 100644
--- a/backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/ir/util/IrUtils2.kt
+++ b/backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/ir/util/IrUtils2.kt
@@ -238,7 +238,7 @@ fun IrBuilderWithScope.irCall(symbol: IrFunctionSymbol, typeArguments: List<IrTy
 fun IrBuilderWithScope.irCall(irFunction: IrFunction, typeArguments: List<IrType> = emptyList()) =
         irCall(irFunction.symbol, typeArguments)
 
-internal fun irCall(startOffset: Int, endOffset: Int, irFunction: IrFunction, typeArguments: List<IrType>): IrCall =
+internal fun irCall(startOffset: Int, endOffset: Int, irFunction: IrSimpleFunction, typeArguments: List<IrType>): IrCall =
         IrCallImpl(
                 startOffset, endOffset, irFunction.substitutedReturnType(typeArguments),
                 irFunction.symbol, typeArguments.size