diff --git a/compiler/fir/fir2ir/tests/org/jetbrains/kotlin/codegen/ir/FirBlackBoxCodegenTestGenerated.java b/compiler/fir/fir2ir/tests/org/jetbrains/kotlin/codegen/ir/FirBlackBoxCodegenTestGenerated.java
index e060073994a..6e7c644d7de 100644
--- a/compiler/fir/fir2ir/tests/org/jetbrains/kotlin/codegen/ir/FirBlackBoxCodegenTestGenerated.java
+++ b/compiler/fir/fir2ir/tests/org/jetbrains/kotlin/codegen/ir/FirBlackBoxCodegenTestGenerated.java
@@ -32257,6 +32257,11 @@ public class FirBlackBoxCodegenTestGenerated extends AbstractFirBlackBoxCodegenT
             runTest("compiler/testData/codegen/box/when/kt2466.kt");
         }
 
+        @TestMetadata("kt43242.kt")
+        public void testKt43242() throws Exception {
+            runTest("compiler/testData/codegen/box/when/kt43242.kt");
+        }
+
         @TestMetadata("kt5307.kt")
         public void testKt5307() throws Exception {
             runTest("compiler/testData/codegen/box/when/kt5307.kt");
diff --git a/compiler/ir/backend.jvm/src/org/jetbrains/kotlin/backend/jvm/codegen/SwitchGenerator.kt b/compiler/ir/backend.jvm/src/org/jetbrains/kotlin/backend/jvm/codegen/SwitchGenerator.kt
index 1d5f54635bb..c7daf2809d6 100644
--- a/compiler/ir/backend.jvm/src/org/jetbrains/kotlin/backend/jvm/codegen/SwitchGenerator.kt
+++ b/compiler/ir/backend.jvm/src/org/jetbrains/kotlin/backend/jvm/codegen/SwitchGenerator.kt
@@ -11,6 +11,7 @@ import org.jetbrains.kotlin.ir.types.*
 import org.jetbrains.kotlin.ir.util.dump
 import org.jetbrains.kotlin.ir.util.isTrueConst
 import org.jetbrains.org.objectweb.asm.Label
+import org.jetbrains.org.objectweb.asm.Type
 import java.util.*
 
 // TODO: eliminate the temporary variable
@@ -367,7 +368,8 @@ class SwitchGenerator(private val expression: IrWhen, private val data: BlockInf
             // information for the subject as the `when` line number has already been
             // emitted.
             codegen.noLineNumberScope {
-                subject.accept(codegen, data).materialize()
+                val subjectValue = subject.accept(codegen, data)
+                subjectValue.materializeAt(Type.INT_TYPE, subjectValue.irType)
             }
             genIntSwitch(cases)
         }
diff --git a/compiler/testData/codegen/box/when/kt43242.kt b/compiler/testData/codegen/box/when/kt43242.kt
new file mode 100644
index 00000000000..5a6c48a85f3
--- /dev/null
+++ b/compiler/testData/codegen/box/when/kt43242.kt
@@ -0,0 +1,28 @@
+// TARGET_BACKEND: JVM
+// FILE: kt43242.kt
+
+fun fromJson() {
+    test = Bar().fromJson()?.let {
+        when (it) {
+            0 -> false
+            1 -> true
+            else -> true
+        }
+    }
+}
+
+var test: Any? = "xxx"
+
+fun box(): String {
+    fromJson()
+    return if (test != null) "Fail: $test" else "OK"
+}
+
+// FILE: Bar.java
+import org.jetbrains.annotations.Nullable;
+
+public class Bar {
+    public final @Nullable Integer fromJson() {
+        return null;
+    }
+}
\ No newline at end of file
diff --git a/compiler/tests/org/jetbrains/kotlin/codegen/BlackBoxCodegenTestGenerated.java b/compiler/tests/org/jetbrains/kotlin/codegen/BlackBoxCodegenTestGenerated.java
index bfb847b9f6e..a7830f03dd5 100644
--- a/compiler/tests/org/jetbrains/kotlin/codegen/BlackBoxCodegenTestGenerated.java
+++ b/compiler/tests/org/jetbrains/kotlin/codegen/BlackBoxCodegenTestGenerated.java
@@ -34028,6 +34028,11 @@ public class BlackBoxCodegenTestGenerated extends AbstractBlackBoxCodegenTest {
             runTest("compiler/testData/codegen/box/when/kt2466.kt");
         }
 
+        @TestMetadata("kt43242.kt")
+        public void testKt43242() throws Exception {
+            runTest("compiler/testData/codegen/box/when/kt43242.kt");
+        }
+
         @TestMetadata("kt5307.kt")
         public void testKt5307() throws Exception {
             runTest("compiler/testData/codegen/box/when/kt5307.kt");
diff --git a/compiler/tests/org/jetbrains/kotlin/codegen/LightAnalysisModeTestGenerated.java b/compiler/tests/org/jetbrains/kotlin/codegen/LightAnalysisModeTestGenerated.java
index 96d8a6ee25b..ac04cff9c25 100644
--- a/compiler/tests/org/jetbrains/kotlin/codegen/LightAnalysisModeTestGenerated.java
+++ b/compiler/tests/org/jetbrains/kotlin/codegen/LightAnalysisModeTestGenerated.java
@@ -31662,6 +31662,11 @@ public class LightAnalysisModeTestGenerated extends AbstractLightAnalysisModeTes
             runTest("compiler/testData/codegen/box/when/kt2466.kt");
         }
 
+        @TestMetadata("kt43242.kt")
+        public void testKt43242() throws Exception {
+            runTest("compiler/testData/codegen/box/when/kt43242.kt");
+        }
+
         @TestMetadata("kt5307.kt")
         public void testKt5307() throws Exception {
             runTest("compiler/testData/codegen/box/when/kt5307.kt");
diff --git a/compiler/tests/org/jetbrains/kotlin/codegen/ir/IrBlackBoxCodegenTestGenerated.java b/compiler/tests/org/jetbrains/kotlin/codegen/ir/IrBlackBoxCodegenTestGenerated.java
index bcf94dd10fe..5df032e166f 100644
--- a/compiler/tests/org/jetbrains/kotlin/codegen/ir/IrBlackBoxCodegenTestGenerated.java
+++ b/compiler/tests/org/jetbrains/kotlin/codegen/ir/IrBlackBoxCodegenTestGenerated.java
@@ -32257,6 +32257,11 @@ public class IrBlackBoxCodegenTestGenerated extends AbstractIrBlackBoxCodegenTes
             runTest("compiler/testData/codegen/box/when/kt2466.kt");
         }
 
+        @TestMetadata("kt43242.kt")
+        public void testKt43242() throws Exception {
+            runTest("compiler/testData/codegen/box/when/kt43242.kt");
+        }
+
         @TestMetadata("kt5307.kt")
         public void testKt5307() throws Exception {
             runTest("compiler/testData/codegen/box/when/kt5307.kt");