diff --git a/compiler/fir/fir2ir/tests-gen/org/jetbrains/kotlin/test/runners/codegen/FirBlackBoxCodegenTestGenerated.java b/compiler/fir/fir2ir/tests-gen/org/jetbrains/kotlin/test/runners/codegen/FirBlackBoxCodegenTestGenerated.java
index e42ef38b5bb..361a1c4c71c 100644
--- a/compiler/fir/fir2ir/tests-gen/org/jetbrains/kotlin/test/runners/codegen/FirBlackBoxCodegenTestGenerated.java
+++ b/compiler/fir/fir2ir/tests-gen/org/jetbrains/kotlin/test/runners/codegen/FirBlackBoxCodegenTestGenerated.java
@@ -23069,6 +23069,12 @@ public class FirBlackBoxCodegenTestGenerated extends AbstractFirBlackBoxCodegenT
             runTest("compiler/testData/codegen/box/inlineClasses/unboxValueOfAnyBeforeMethodInvocationGeneric2.kt", TransformersFunctions.getReplaceOptionalJvmInlineAnnotationWithReal());
         }
 
+        @Test
+        @TestMetadata("unboxValueOfNullableInlineClassUsingInlineFunction.kt")
+        public void testUnboxValueOfNullableInlineClassUsingInlineFunction() throws Exception {
+            runTest("compiler/testData/codegen/box/inlineClasses/unboxValueOfNullableInlineClassUsingInlineFunction.kt", TransformersFunctions.getReplaceOptionalJvmInlineAnnotationWithReal());
+        }
+
         @Test
         @TestMetadata("useInlineClassesInsideElvisOperator.kt")
         public void testUseInlineClassesInsideElvisOperator() throws Exception {
diff --git a/compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/lower/AutoboxingTransformer.kt b/compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/lower/AutoboxingTransformer.kt
index 91ad2f10ced..b6eff9aaab4 100644
--- a/compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/lower/AutoboxingTransformer.kt
+++ b/compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/lower/AutoboxingTransformer.kt
@@ -11,7 +11,6 @@ import org.jetbrains.kotlin.backend.common.lower.AbstractValueUsageTransformer
 import org.jetbrains.kotlin.backend.common.pop
 import org.jetbrains.kotlin.backend.common.push
 import org.jetbrains.kotlin.ir.IrBuiltIns
-import org.jetbrains.kotlin.ir.IrStatement
 import org.jetbrains.kotlin.ir.backend.js.JsCommonBackendContext
 import org.jetbrains.kotlin.ir.backend.js.ir.JsIrBuilder
 import org.jetbrains.kotlin.ir.backend.js.utils.realOverrideTarget
@@ -136,14 +135,6 @@ class AutoboxingTransformer(context: JsCommonBackendContext) : AbstractValueUsag
         return res
     }
 
-    override fun visitFunction(declaration: IrFunction): IrStatement {
-        return super.visitFunction(declaration)
-    }
-
-    override fun visitVararg(expression: IrVararg): IrExpression {
-        return super.visitVararg(expression)
-    }
-
     override fun IrExpression.useAsResult(enclosing: IrExpression): IrExpression {
         if (processingReturnStack.lastOrNull()?.value == enclosing && enclosing is IrReturnableBlock) {
             return useReturnableExpressionAsType(enclosing.type)
diff --git a/compiler/ir/backend.wasm/src/org/jetbrains/kotlin/backend/wasm/ir2wasm/BodyGenerator.kt b/compiler/ir/backend.wasm/src/org/jetbrains/kotlin/backend/wasm/ir2wasm/BodyGenerator.kt
index b5d1829d399..79c6423eccd 100644
--- a/compiler/ir/backend.wasm/src/org/jetbrains/kotlin/backend/wasm/ir2wasm/BodyGenerator.kt
+++ b/compiler/ir/backend.wasm/src/org/jetbrains/kotlin/backend/wasm/ir2wasm/BodyGenerator.kt
@@ -739,7 +739,11 @@ class BodyGenerator(
 
         // REF -> REF -> REF_CAST
         if (!expectedIsPrimitive) {
-            generateRefNullCast(actualTypeErased, expectedTypeErased)
+            if (expectedClassErased.isSubclassOf(actualClassErased)) {
+                generateRefNullCast(actualTypeErased, expectedTypeErased)
+            } else {
+                body.buildUnreachable()
+            }
         }
     }
 
diff --git a/compiler/testData/codegen/box/inlineClasses/unboxValueOfNullableInlineClassUsingInlineFunction.kt b/compiler/testData/codegen/box/inlineClasses/unboxValueOfNullableInlineClassUsingInlineFunction.kt
new file mode 100644
index 00000000000..0140e98d3ba
--- /dev/null
+++ b/compiler/testData/codegen/box/inlineClasses/unboxValueOfNullableInlineClassUsingInlineFunction.kt
@@ -0,0 +1,8 @@
+// WITH_STDLIB
+// WORKS_WHEN_VALUE_CLASS
+// LANGUAGE: +ValueClasses
+
+inline class X(val i: Int)
+fun unbox(x: X?): Int = checkNotNull(x).i
+
+fun box(): String = if (unbox(X(42)) == 42) "OK" else "Fail"
\ No newline at end of file
diff --git a/compiler/tests-common-new/tests-gen/org/jetbrains/kotlin/test/runners/codegen/BlackBoxCodegenTestGenerated.java b/compiler/tests-common-new/tests-gen/org/jetbrains/kotlin/test/runners/codegen/BlackBoxCodegenTestGenerated.java
index 0156774c086..e79df87a106 100644
--- a/compiler/tests-common-new/tests-gen/org/jetbrains/kotlin/test/runners/codegen/BlackBoxCodegenTestGenerated.java
+++ b/compiler/tests-common-new/tests-gen/org/jetbrains/kotlin/test/runners/codegen/BlackBoxCodegenTestGenerated.java
@@ -22127,6 +22127,12 @@ public class BlackBoxCodegenTestGenerated extends AbstractBlackBoxCodegenTest {
             runTest("compiler/testData/codegen/box/inlineClasses/unboxValueOfAnyBeforeMethodInvocationGeneric2.kt", TransformersFunctions.getReplaceOptionalJvmInlineAnnotationWithReal());
         }
 
+        @Test
+        @TestMetadata("unboxValueOfNullableInlineClassUsingInlineFunction.kt")
+        public void testUnboxValueOfNullableInlineClassUsingInlineFunction() throws Exception {
+            runTest("compiler/testData/codegen/box/inlineClasses/unboxValueOfNullableInlineClassUsingInlineFunction.kt", TransformersFunctions.getReplaceOptionalJvmInlineAnnotationWithReal());
+        }
+
         @Test
         @TestMetadata("useInlineClassesInsideElvisOperator.kt")
         public void testUseInlineClassesInsideElvisOperator() throws Exception {
diff --git a/compiler/tests-common-new/tests-gen/org/jetbrains/kotlin/test/runners/codegen/IrBlackBoxCodegenTestGenerated.java b/compiler/tests-common-new/tests-gen/org/jetbrains/kotlin/test/runners/codegen/IrBlackBoxCodegenTestGenerated.java
index 83de966d230..3bd411e0bd6 100644
--- a/compiler/tests-common-new/tests-gen/org/jetbrains/kotlin/test/runners/codegen/IrBlackBoxCodegenTestGenerated.java
+++ b/compiler/tests-common-new/tests-gen/org/jetbrains/kotlin/test/runners/codegen/IrBlackBoxCodegenTestGenerated.java
@@ -23069,6 +23069,12 @@ public class IrBlackBoxCodegenTestGenerated extends AbstractIrBlackBoxCodegenTes
             runTest("compiler/testData/codegen/box/inlineClasses/unboxValueOfAnyBeforeMethodInvocationGeneric2.kt", TransformersFunctions.getReplaceOptionalJvmInlineAnnotationWithReal());
         }
 
+        @Test
+        @TestMetadata("unboxValueOfNullableInlineClassUsingInlineFunction.kt")
+        public void testUnboxValueOfNullableInlineClassUsingInlineFunction() throws Exception {
+            runTest("compiler/testData/codegen/box/inlineClasses/unboxValueOfNullableInlineClassUsingInlineFunction.kt", TransformersFunctions.getReplaceOptionalJvmInlineAnnotationWithReal());
+        }
+
         @Test
         @TestMetadata("useInlineClassesInsideElvisOperator.kt")
         public void testUseInlineClassesInsideElvisOperator() throws Exception {
diff --git a/compiler/tests-gen/org/jetbrains/kotlin/codegen/LightAnalysisModeTestGenerated.java b/compiler/tests-gen/org/jetbrains/kotlin/codegen/LightAnalysisModeTestGenerated.java
index 401f08c6e78..666be14d5f3 100644
--- a/compiler/tests-gen/org/jetbrains/kotlin/codegen/LightAnalysisModeTestGenerated.java
+++ b/compiler/tests-gen/org/jetbrains/kotlin/codegen/LightAnalysisModeTestGenerated.java
@@ -18435,6 +18435,11 @@ public class LightAnalysisModeTestGenerated extends AbstractLightAnalysisModeTes
             runTest("compiler/testData/codegen/box/inlineClasses/unboxValueOfAnyBeforeMethodInvocationGeneric2.kt", TransformersFunctions.getReplaceOptionalJvmInlineAnnotationWithReal());
         }
 
+        @TestMetadata("unboxValueOfNullableInlineClassUsingInlineFunction.kt")
+        public void testUnboxValueOfNullableInlineClassUsingInlineFunction() throws Exception {
+            runTest("compiler/testData/codegen/box/inlineClasses/unboxValueOfNullableInlineClassUsingInlineFunction.kt", TransformersFunctions.getReplaceOptionalJvmInlineAnnotationWithReal());
+        }
+
         @TestMetadata("useInlineClassesInsideElvisOperator.kt")
         public void testUseInlineClassesInsideElvisOperator() throws Exception {
             runTest("compiler/testData/codegen/box/inlineClasses/useInlineClassesInsideElvisOperator.kt", TransformersFunctions.getReplaceOptionalJvmInlineAnnotationWithReal());
diff --git a/js/js.tests/tests-gen/org/jetbrains/kotlin/js/test/JsCodegenBoxTestGenerated.java b/js/js.tests/tests-gen/org/jetbrains/kotlin/js/test/JsCodegenBoxTestGenerated.java
index 28a48261aff..74a37e81388 100644
--- a/js/js.tests/tests-gen/org/jetbrains/kotlin/js/test/JsCodegenBoxTestGenerated.java
+++ b/js/js.tests/tests-gen/org/jetbrains/kotlin/js/test/JsCodegenBoxTestGenerated.java
@@ -17479,6 +17479,12 @@ public class JsCodegenBoxTestGenerated extends AbstractJsCodegenBoxTest {
             runTest("compiler/testData/codegen/box/inlineClasses/unboxValueOfAnyBeforeMethodInvocationGeneric2.kt", TransformersFunctions.getRemoveOptionalJvmInlineAnnotation());
         }
 
+        @Test
+        @TestMetadata("unboxValueOfNullableInlineClassUsingInlineFunction.kt")
+        public void testUnboxValueOfNullableInlineClassUsingInlineFunction() throws Exception {
+            runTest("compiler/testData/codegen/box/inlineClasses/unboxValueOfNullableInlineClassUsingInlineFunction.kt", TransformersFunctions.getRemoveOptionalJvmInlineAnnotation());
+        }
+
         @Test
         @TestMetadata("useInlineClassesInsideElvisOperator.kt")
         public void testUseInlineClassesInsideElvisOperator() throws Exception {
diff --git a/js/js.tests/tests-gen/org/jetbrains/kotlin/js/test/fir/FirJsCodegenBoxTestGenerated.java b/js/js.tests/tests-gen/org/jetbrains/kotlin/js/test/fir/FirJsCodegenBoxTestGenerated.java
index f24aa01356a..63425c5c70f 100644
--- a/js/js.tests/tests-gen/org/jetbrains/kotlin/js/test/fir/FirJsCodegenBoxTestGenerated.java
+++ b/js/js.tests/tests-gen/org/jetbrains/kotlin/js/test/fir/FirJsCodegenBoxTestGenerated.java
@@ -17497,6 +17497,12 @@ public class FirJsCodegenBoxTestGenerated extends AbstractFirJsCodegenBoxTest {
             runTest("compiler/testData/codegen/box/inlineClasses/unboxValueOfAnyBeforeMethodInvocationGeneric2.kt", TransformersFunctions.getRemoveOptionalJvmInlineAnnotation());
         }
 
+        @Test
+        @TestMetadata("unboxValueOfNullableInlineClassUsingInlineFunction.kt")
+        public void testUnboxValueOfNullableInlineClassUsingInlineFunction() throws Exception {
+            runTest("compiler/testData/codegen/box/inlineClasses/unboxValueOfNullableInlineClassUsingInlineFunction.kt", TransformersFunctions.getRemoveOptionalJvmInlineAnnotation());
+        }
+
         @Test
         @TestMetadata("useInlineClassesInsideElvisOperator.kt")
         public void testUseInlineClassesInsideElvisOperator() throws Exception {
diff --git a/js/js.tests/tests-gen/org/jetbrains/kotlin/js/test/ir/IrJsCodegenBoxTestGenerated.java b/js/js.tests/tests-gen/org/jetbrains/kotlin/js/test/ir/IrJsCodegenBoxTestGenerated.java
index 2ff2baf3342..f817699886e 100644
--- a/js/js.tests/tests-gen/org/jetbrains/kotlin/js/test/ir/IrJsCodegenBoxTestGenerated.java
+++ b/js/js.tests/tests-gen/org/jetbrains/kotlin/js/test/ir/IrJsCodegenBoxTestGenerated.java
@@ -17497,6 +17497,12 @@ public class IrJsCodegenBoxTestGenerated extends AbstractIrJsCodegenBoxTest {
             runTest("compiler/testData/codegen/box/inlineClasses/unboxValueOfAnyBeforeMethodInvocationGeneric2.kt", TransformersFunctions.getRemoveOptionalJvmInlineAnnotation());
         }
 
+        @Test
+        @TestMetadata("unboxValueOfNullableInlineClassUsingInlineFunction.kt")
+        public void testUnboxValueOfNullableInlineClassUsingInlineFunction() throws Exception {
+            runTest("compiler/testData/codegen/box/inlineClasses/unboxValueOfNullableInlineClassUsingInlineFunction.kt", TransformersFunctions.getRemoveOptionalJvmInlineAnnotation());
+        }
+
         @Test
         @TestMetadata("useInlineClassesInsideElvisOperator.kt")
         public void testUseInlineClassesInsideElvisOperator() throws Exception {
diff --git a/js/js.tests/tests-gen/org/jetbrains/kotlin/js/testOld/wasm/semantics/IrCodegenBoxWasmTestGenerated.java b/js/js.tests/tests-gen/org/jetbrains/kotlin/js/testOld/wasm/semantics/IrCodegenBoxWasmTestGenerated.java
index c69d5b88dbd..6d16196e87b 100644
--- a/js/js.tests/tests-gen/org/jetbrains/kotlin/js/testOld/wasm/semantics/IrCodegenBoxWasmTestGenerated.java
+++ b/js/js.tests/tests-gen/org/jetbrains/kotlin/js/testOld/wasm/semantics/IrCodegenBoxWasmTestGenerated.java
@@ -15465,6 +15465,11 @@ public class IrCodegenBoxWasmTestGenerated extends AbstractIrCodegenBoxWasmTest
             runTest("compiler/testData/codegen/box/inlineClasses/unboxValueOfAnyBeforeMethodInvocationGeneric2.kt", TransformersFunctions.getRemoveOptionalJvmInlineAnnotation());
         }
 
+        @TestMetadata("unboxValueOfNullableInlineClassUsingInlineFunction.kt")
+        public void testUnboxValueOfNullableInlineClassUsingInlineFunction() throws Exception {
+            runTest("compiler/testData/codegen/box/inlineClasses/unboxValueOfNullableInlineClassUsingInlineFunction.kt", TransformersFunctions.getRemoveOptionalJvmInlineAnnotation());
+        }
+
         @TestMetadata("useInlineClassesInsideElvisOperator.kt")
         public void testUseInlineClassesInsideElvisOperator() throws Exception {
             runTest("compiler/testData/codegen/box/inlineClasses/useInlineClassesInsideElvisOperator.kt", TransformersFunctions.getRemoveOptionalJvmInlineAnnotation());
diff --git a/native/native.tests/tests-gen/org/jetbrains/kotlin/konan/blackboxtest/NativeCodegenBoxTestGenerated.java b/native/native.tests/tests-gen/org/jetbrains/kotlin/konan/blackboxtest/NativeCodegenBoxTestGenerated.java
index 706c8aa56d3..21b2f65e3a3 100644
--- a/native/native.tests/tests-gen/org/jetbrains/kotlin/konan/blackboxtest/NativeCodegenBoxTestGenerated.java
+++ b/native/native.tests/tests-gen/org/jetbrains/kotlin/konan/blackboxtest/NativeCodegenBoxTestGenerated.java
@@ -16929,6 +16929,7 @@ public class NativeCodegenBoxTestGenerated extends AbstractNativeCodegenBoxTest
                 register("compiler/testData/codegen/box/inlineClasses/unboxValueOfAnyBeforeMethodInvocation.kt", TransformersFunctions.getRemoveOptionalJvmInlineAnnotation());
                 register("compiler/testData/codegen/box/inlineClasses/unboxValueOfAnyBeforeMethodInvocationGeneric.kt", TransformersFunctions.getRemoveOptionalJvmInlineAnnotation());
                 register("compiler/testData/codegen/box/inlineClasses/unboxValueOfAnyBeforeMethodInvocationGeneric2.kt", TransformersFunctions.getRemoveOptionalJvmInlineAnnotation());
+                register("compiler/testData/codegen/box/inlineClasses/unboxValueOfNullableInlineClassUsingInlineFunction.kt", TransformersFunctions.getRemoveOptionalJvmInlineAnnotation());
                 register("compiler/testData/codegen/box/inlineClasses/useInlineClassesInsideElvisOperator.kt", TransformersFunctions.getRemoveOptionalJvmInlineAnnotation());
                 register("compiler/testData/codegen/box/inlineClasses/useInlineClassesInsideElvisOperatorGeneric.kt", TransformersFunctions.getRemoveOptionalJvmInlineAnnotation());
                 register("compiler/testData/codegen/box/inlineClasses/useInlineFunctionInsideInlineClass.kt", TransformersFunctions.getRemoveOptionalJvmInlineAnnotation());
@@ -19302,6 +19303,13 @@ public class NativeCodegenBoxTestGenerated extends AbstractNativeCodegenBoxTest
                 runTest("compiler/testData/codegen/box/inlineClasses/unboxValueOfAnyBeforeMethodInvocationGeneric2.kt");
             }
 
+            @Test
+            @TestMetadata("unboxValueOfNullableInlineClassUsingInlineFunction.kt")
+            public void testUnboxValueOfNullableInlineClassUsingInlineFunction() throws Exception {
+                // There is a registered source transformer for the testcase: TransformersFunctions.getRemoveOptionalJvmInlineAnnotation()
+                runTest("compiler/testData/codegen/box/inlineClasses/unboxValueOfNullableInlineClassUsingInlineFunction.kt");
+            }
+
             @Test
             @TestMetadata("useInlineClassesInsideElvisOperator.kt")
             public void testUseInlineClassesInsideElvisOperator() throws Exception {