diff --git a/backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/lower/FunctionInlining.kt b/backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/lower/FunctionInlining.kt
index 4be8f7ef4a6..96e8c308b80 100644
--- a/backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/lower/FunctionInlining.kt
+++ b/backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/lower/FunctionInlining.kt
@@ -211,7 +211,7 @@ internal class FunctionInlining(val context: Context): IrElementTransformerVoid(
     private fun inlineFunction(irCall: IrCall): IrExpression {
 
         val irDeclaration = getFunctionDeclaration(irCall)
-        if (irDeclaration == null) return irCall
+        assert (irDeclaration != null) { "Inliner failed to obtain function declaration" }
 
         val functionDeclaration = irDeclaration as IrFunction
         val typeArgsMap = (irCall as IrMemberAccessExpressionBase).typeArguments