diff --git a/compiler/fir/analysis-tests/testData/resolve/arguments/setWithTrailingLambda.fir.txt b/compiler/fir/analysis-tests/testData/resolve/arguments/setWithTrailingLambda.fir.txt
index 59b2b72ff83..fb008473e7f 100644
--- a/compiler/fir/analysis-tests/testData/resolve/arguments/setWithTrailingLambda.fir.txt
+++ b/compiler/fir/analysis-tests/testData/resolve/arguments/setWithTrailingLambda.fir.txt
@@ -8,6 +8,7 @@ FILE: setWithTrailingLambda.kt
             ^ Unit
         }
         )
+        Unit
     }
     public final data class EditorData : R|kotlin/Any| {
         public constructor(meta: R|MyMap<EditorData, kotlin/Any>|): R|EditorData| {
diff --git a/compiler/fir/analysis-tests/testData/resolve/arrays/arraySet.fir.txt b/compiler/fir/analysis-tests/testData/resolve/arrays/arraySet.fir.txt
index c97776166dc..82e0b661637 100644
--- a/compiler/fir/analysis-tests/testData/resolve/arrays/arraySet.fir.txt
+++ b/compiler/fir/analysis-tests/testData/resolve/arrays/arraySet.fir.txt
@@ -46,10 +46,13 @@ FILE: arraySet.kt
     }
     public final fun test_1(a: R|A<B>|): R|kotlin/Unit| {
         R|<local>/a|.R|SubstitutionOverride</A.set: R|kotlin/Unit|>|(Int(0), R|/B.B|())
+        Unit
     }
     public final fun test_2(a: R|A<C>|): R|kotlin/Unit| {
         R|<local>/a|.R|SubstitutionOverride</A.set: R|kotlin/Unit|>|(Int(0), R|/C.C|())
+        Unit
     }
     public final fun test_3(a: R|A<D>|): R|kotlin/Unit| {
         R|<local>/a|.R|SubstitutionOverride</A.set: R|kotlin/Unit|>|(Int(0), R|/D.D|())
+        Unit
     }
diff --git a/compiler/fir/analysis-tests/testData/resolve/checkers/notUselessCast_3.fir.txt b/compiler/fir/analysis-tests/testData/resolve/checkers/notUselessCast_3.fir.txt
index ccd167341ae..01845480a98 100644
--- a/compiler/fir/analysis-tests/testData/resolve/checkers/notUselessCast_3.fir.txt
+++ b/compiler/fir/analysis-tests/testData/resolve/checkers/notUselessCast_3.fir.txt
@@ -26,6 +26,7 @@ FILE: notUselessCast_3.kt
         }
         )
         R|<local>/cards|.R|SubstitutionOverride<kotlin/collections/List.get: R|kotlin/collections/List<kotlin/collections/MutableList<Square>>|>|(Int(0)).R|SubstitutionOverride<kotlin/collections/List.get: R|kotlin/collections/MutableList<Square>|>|(Int(0)).R|SubstitutionOverride<kotlin/collections/MutableList.set: R|Square|>|(Int(0), Q|MARKED|)
+        Unit
     }
     public final fun test_2(): R|kotlin/Unit| {
         lval lines: R|kotlin/collections/List<kotlin/String>| = R|kotlin/collections/listOf|<R|kotlin/String|>()
@@ -40,4 +41,5 @@ FILE: notUselessCast_3.kt
         }
         )
         R|<local>/cards|.R|SubstitutionOverride<kotlin/collections/List.get: R|kotlin/collections/List<kotlin/collections/MutableList<UNMARKED>>|>|(Int(0)).R|SubstitutionOverride<kotlin/collections/List.get: R|kotlin/collections/MutableList<UNMARKED>|>|(Int(0)).R|SubstitutionOverride<kotlin/collections/MutableList.set: R|UNMARKED|><Inapplicable(INAPPLICABLE): kotlin/collections/MutableList.set>#|(Int(0), Q|MARKED|)
+        Unit
     }
diff --git a/compiler/fir/analysis-tests/testData/resolveWithStdlib/typeAliasWithForEach.fir.txt b/compiler/fir/analysis-tests/testData/resolveWithStdlib/typeAliasWithForEach.fir.txt
index 73a9970cfda..de414a6595d 100644
--- a/compiler/fir/analysis-tests/testData/resolveWithStdlib/typeAliasWithForEach.fir.txt
+++ b/compiler/fir/analysis-tests/testData/resolveWithStdlib/typeAliasWithForEach.fir.txt
@@ -12,6 +12,7 @@ FILE: typeAliasWithForEach.kt
         lval result: R|java/util/HashMap<kotlin/String, ArgsInfo>| = R|java/util/HashMap.HashMap|<R|kotlin/String|, R|ArgsInfo|>()
         this@R|/deepCopy|.R|SubstitutionOverride<kotlin/collections/Map.forEach: R|kotlin/Unit|>|(<L> = forEach@fun <anonymous>(key: R|@EnhancedNullability kotlin/String|, value: R|@EnhancedNullability ArgsInfo|): R|kotlin/Unit| <inline=NoInline>  {
             R|<local>/result|.R|kotlin/collections/set|<R|kotlin/String|, R|ArgsInfo|>(R|<local>/key|, R|/ArgsInfoImpl.ArgsInfoImpl|(R|<local>/value|))
+            Unit
         }
         )
         ^deepCopy R|<local>/result|
diff --git a/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/expression/FirFunctionReturnTypeMismatchChecker.kt b/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/expression/FirFunctionReturnTypeMismatchChecker.kt
index d116a83542d..c77f14f26fa 100644
--- a/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/expression/FirFunctionReturnTypeMismatchChecker.kt
+++ b/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/expression/FirFunctionReturnTypeMismatchChecker.kt
@@ -88,7 +88,7 @@ object FirFunctionReturnTypeMismatchChecker : FirReturnExpressionChecker() {
                     )
                 }
             }
-        } else if (resultExpression.source?.kind == KtFakeSourceElementKind.ImplicitUnit && !functionReturnType.isUnit) {
+        } else if (resultExpression.source?.kind is KtFakeSourceElementKind.ImplicitUnit && !functionReturnType.isUnit) {
             reporter.reportOn(
                 resultExpression.source,
                 RETURN_TYPE_MISMATCH,
diff --git a/compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/backend/Fir2IrVisitor.kt b/compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/backend/Fir2IrVisitor.kt
index f4624b9a835..e36a2bfd52e 100644
--- a/compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/backend/Fir2IrVisitor.kt
+++ b/compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/backend/Fir2IrVisitor.kt
@@ -56,6 +56,7 @@ import org.jetbrains.kotlin.psi.KtBinaryExpression
 import org.jetbrains.kotlin.psi.KtForExpression
 import org.jetbrains.kotlin.types.Variance
 import org.jetbrains.kotlin.util.OperatorNameConventions
+import org.jetbrains.kotlin.utils.addToStdlib.runUnless
 
 class Fir2IrVisitor(
     private val components: Fir2IrComponents,
@@ -758,7 +759,9 @@ class Fir2IrVisitor(
 
     private fun FirStatement.toIrStatement(): IrStatement? {
         if (this is FirTypeAlias) return null
-        if (this is FirUnitExpression) return convertToIrExpression(this)
+        if (this is FirUnitExpression) return runUnless(source?.kind is KtFakeSourceElementKind.ImplicitUnit.IndexedAssignmentCoercion) {
+            convertToIrExpression(this)
+        }
         if (this is FirContractCallBlock) return null
         if (this is FirBlock) return convertToIrExpression(this)
         return accept(this@Fir2IrVisitor, null) as IrStatement
diff --git a/compiler/fir/fir2ir/tests-gen/org/jetbrains/kotlin/test/runners/codegen/FirLightTreeBlackBoxCodegenTestGenerated.java b/compiler/fir/fir2ir/tests-gen/org/jetbrains/kotlin/test/runners/codegen/FirLightTreeBlackBoxCodegenTestGenerated.java
index e527b9ebb8d..feeac1af083 100644
--- a/compiler/fir/fir2ir/tests-gen/org/jetbrains/kotlin/test/runners/codegen/FirLightTreeBlackBoxCodegenTestGenerated.java
+++ b/compiler/fir/fir2ir/tests-gen/org/jetbrains/kotlin/test/runners/codegen/FirLightTreeBlackBoxCodegenTestGenerated.java
@@ -18587,6 +18587,12 @@ public class FirLightTreeBlackBoxCodegenTestGenerated extends AbstractFirLightTr
             runTest("compiler/testData/codegen/box/fir/linkViaSignatures.kt");
         }
 
+        @Test
+        @TestMetadata("listAssignmentInWhen.kt")
+        public void testListAssignmentInWhen() throws Exception {
+            runTest("compiler/testData/codegen/box/fir/listAssignmentInWhen.kt");
+        }
+
         @Test
         @TestMetadata("localInvokeExtension.kt")
         public void testLocalInvokeExtension() throws Exception {
diff --git a/compiler/fir/fir2ir/tests-gen/org/jetbrains/kotlin/test/runners/codegen/FirPsiBlackBoxCodegenTestGenerated.java b/compiler/fir/fir2ir/tests-gen/org/jetbrains/kotlin/test/runners/codegen/FirPsiBlackBoxCodegenTestGenerated.java
index decce16a244..a88428b6537 100644
--- a/compiler/fir/fir2ir/tests-gen/org/jetbrains/kotlin/test/runners/codegen/FirPsiBlackBoxCodegenTestGenerated.java
+++ b/compiler/fir/fir2ir/tests-gen/org/jetbrains/kotlin/test/runners/codegen/FirPsiBlackBoxCodegenTestGenerated.java
@@ -18587,6 +18587,12 @@ public class FirPsiBlackBoxCodegenTestGenerated extends AbstractFirPsiBlackBoxCo
             runTest("compiler/testData/codegen/box/fir/linkViaSignatures.kt");
         }
 
+        @Test
+        @TestMetadata("listAssignmentInWhen.kt")
+        public void testListAssignmentInWhen() throws Exception {
+            runTest("compiler/testData/codegen/box/fir/listAssignmentInWhen.kt");
+        }
+
         @Test
         @TestMetadata("localInvokeExtension.kt")
         public void testLocalInvokeExtension() throws Exception {
diff --git a/compiler/fir/raw-fir/light-tree2fir/src/org/jetbrains/kotlin/fir/lightTree/converter/LightTreeRawFirExpressionBuilder.kt b/compiler/fir/raw-fir/light-tree2fir/src/org/jetbrains/kotlin/fir/lightTree/converter/LightTreeRawFirExpressionBuilder.kt
index 0479d6807fb..2bf457c1fff 100644
--- a/compiler/fir/raw-fir/light-tree2fir/src/org/jetbrains/kotlin/fir/lightTree/converter/LightTreeRawFirExpressionBuilder.kt
+++ b/compiler/fir/raw-fir/light-tree2fir/src/org/jetbrains/kotlin/fir/lightTree/converter/LightTreeRawFirExpressionBuilder.kt
@@ -203,7 +203,7 @@ class LightTreeRawFirExpressionBuilder(
                                 source = expressionSource.fakeElement(KtFakeSourceElementKind.ImplicitReturn.FromExpressionBody)
                                 this.target = target
                                 result = buildUnitExpression {
-                                    source = expressionSource.fakeElement(KtFakeSourceElementKind.ImplicitUnit)
+                                    source = expressionSource.fakeElement(KtFakeSourceElementKind.ImplicitUnit.LambdaCoercion)
                                 }
                             }
                         )
@@ -1391,7 +1391,7 @@ class LightTreeRawFirExpressionBuilder(
         }
 
         val calculatedFirExpression = firExpression ?: buildUnitExpression {
-            source = returnExpression.toFirSourceElement(KtFakeSourceElementKind.ImplicitUnit)
+            source = returnExpression.toFirSourceElement(KtFakeSourceElementKind.ImplicitUnit.Return)
         }
         return calculatedFirExpression.toReturn(
             baseSource = returnExpression.toFirSourceElement(),
diff --git a/compiler/fir/raw-fir/psi2fir/src/org/jetbrains/kotlin/fir/builder/PsiRawFirBuilder.kt b/compiler/fir/raw-fir/psi2fir/src/org/jetbrains/kotlin/fir/builder/PsiRawFirBuilder.kt
index 06a3526a091..da822651793 100644
--- a/compiler/fir/raw-fir/psi2fir/src/org/jetbrains/kotlin/fir/builder/PsiRawFirBuilder.kt
+++ b/compiler/fir/raw-fir/psi2fir/src/org/jetbrains/kotlin/fir/builder/PsiRawFirBuilder.kt
@@ -1752,7 +1752,7 @@ open class PsiRawFirBuilder(
                                     source = expressionSource.fakeElement(KtFakeSourceElementKind.ImplicitReturn.FromExpressionBody)
                                     this.target = target
                                     result = buildUnitExpression {
-                                        source = expressionSource.fakeElement(KtFakeSourceElementKind.ImplicitUnit)
+                                        source = expressionSource.fakeElement(KtFakeSourceElementKind.ImplicitUnit.LambdaCoercion)
                                     }
                                 }
                             )
@@ -2269,7 +2269,7 @@ open class PsiRawFirBuilder(
         }
 
         override fun visitReturnExpression(expression: KtReturnExpression, data: FirElement?): FirElement {
-            val source = expression.toFirSourceElement(KtFakeSourceElementKind.ImplicitUnit)
+            val source = expression.toFirSourceElement(KtFakeSourceElementKind.ImplicitUnit.Return)
             val result = expression.returnedExpression?.toFirExpression("Incorrect return expression")
                 ?: buildUnitExpression { this.source = source }
             return result.toReturn(source, expression.getTargetLabel()?.getReferencedName(), fromKtReturnExpression = true)
diff --git a/compiler/fir/raw-fir/psi2fir/testData/rawBuilder/expressions/arrayAssignment.txt b/compiler/fir/raw-fir/psi2fir/testData/rawBuilder/expressions/arrayAssignment.txt
index 3957425d5e6..df83ca6edb2 100644
--- a/compiler/fir/raw-fir/psi2fir/testData/rawBuilder/expressions/arrayAssignment.txt
+++ b/compiler/fir/raw-fir/psi2fir/testData/rawBuilder/expressions/arrayAssignment.txt
@@ -2,10 +2,12 @@ FILE: arrayAssignment.kt
     public? final? fun test(): R|kotlin/Unit| {
         lval x: <implicit> = intArrayOf#(IntegerLiteral(1), IntegerLiteral(2), IntegerLiteral(3))
         x#.set#(IntegerLiteral(1), IntegerLiteral(0))
+        Unit
     }
     public? final? fun foo(): <implicit> {
         ^foo IntegerLiteral(1)
     }
     public? final? fun test2(): R|kotlin/Unit| {
         intArrayOf#(IntegerLiteral(1), IntegerLiteral(2), IntegerLiteral(3)).set#(foo#(), IntegerLiteral(1))
+        Unit
     }
diff --git a/compiler/fir/raw-fir/psi2fir/testData/rawBuilder/expressions/safeCallsWithAssignment.txt b/compiler/fir/raw-fir/psi2fir/testData/rawBuilder/expressions/safeCallsWithAssignment.txt
index 97ff3dbde80..01de1224e5d 100644
--- a/compiler/fir/raw-fir/psi2fir/testData/rawBuilder/expressions/safeCallsWithAssignment.txt
+++ b/compiler/fir/raw-fir/psi2fir/testData/rawBuilder/expressions/safeCallsWithAssignment.txt
@@ -4,10 +4,16 @@ FILE: safeCallsWithAssignment.kt
         a#?.{ $subj$.b# }?.{ $subj$.c# = IntegerLiteral(1) }
         a#?.{ $subj$.b# }.c# = IntegerLiteral(1)
         a#?.{ $subj$.b#.set#(IntegerLiteral(0), IntegerLiteral(1)) }
+        Unit
         a#?.{ $subj$.b# }?.{ $subj$.c#.set#(IntegerLiteral(0), IntegerLiteral(1)) }
+        Unit
         a#?.{ $subj$.b# }.c#.set#(IntegerLiteral(0), IntegerLiteral(1))
+        Unit
         a#?.{ $subj$.b#.get#(IntegerLiteral(0)).set#(IntegerLiteral(0), IntegerLiteral(1)) }
+        Unit
         a#?.{ $subj$.b# }?.{ $subj$.c#.get#(IntegerLiteral(0)).set#(IntegerLiteral(0), IntegerLiteral(1)) }
+        Unit
         a#?.{ $subj$.b# }.c#.get#(IntegerLiteral(0)).set#(IntegerLiteral(0), IntegerLiteral(1))
+        Unit
         a#?.{ $subj$.b# }.d#() = IntegerLiteral(1)
     }
diff --git a/compiler/fir/raw-fir/raw-fir.common/src/org/jetbrains/kotlin/fir/builder/AbstractRawFirBuilder.kt b/compiler/fir/raw-fir/raw-fir.common/src/org/jetbrains/kotlin/fir/builder/AbstractRawFirBuilder.kt
index dadb5de567d..4a20cdbbd66 100644
--- a/compiler/fir/raw-fir/raw-fir.common/src/org/jetbrains/kotlin/fir/builder/AbstractRawFirBuilder.kt
+++ b/compiler/fir/raw-fir/raw-fir.common/src/org/jetbrains/kotlin/fir/builder/AbstractRawFirBuilder.kt
@@ -749,7 +749,13 @@ abstract class AbstractRawFirBuilder<T>(val baseSession: FirSession, val context
             return if (operation == FirOperation.ASSIGN) {
                 val result = unwrappedLhs.convert()
                 result.replaceAnnotations(result.annotations.smartPlus(annotations))
-                result.pullUpSafeCallIfNecessary()
+                buildBlock {
+                    source = result.source
+                    statements += result.pullUpSafeCallIfNecessary()
+                    statements += buildUnitExpression {
+                        source = result.source?.fakeElement(KtFakeSourceElementKind.ImplicitUnit.IndexedAssignmentCoercion)
+                    }
+                }
             } else {
                 val receiver = unwrappedLhs.convert()
 
diff --git a/compiler/frontend.common/src/org/jetbrains/kotlin/KtSourceElement.kt b/compiler/frontend.common/src/org/jetbrains/kotlin/KtSourceElement.kt
index c87c7bcdd6d..bed25c4d591 100644
--- a/compiler/frontend.common/src/org/jetbrains/kotlin/KtSourceElement.kt
+++ b/compiler/frontend.common/src/org/jetbrains/kotlin/KtSourceElement.kt
@@ -86,9 +86,19 @@ sealed class KtFakeSourceElementKind(final override val shouldSkipErrorTypeRepor
         object FromLastStatement : ImplicitReturn()
     }
 
-    // return expression in procedures -> return Unit
-    // with a fake sources which refers to the return statement
-    object ImplicitUnit : KtFakeSourceElementKind()
+    sealed class ImplicitUnit : KtFakeSourceElementKind() {
+        // this source is used for implicit returns from empty lambdas {}
+        // fake source refers to the lambda expression
+        object LambdaCoercion : ImplicitUnit()
+
+        // this source is used for 'return' without given value converted to 'return Unit'
+        // fake source refers to the return statement
+        object Return : ImplicitUnit()
+
+        // this source is used for 'a[i] = b' converted to { a[i] = b; Unit }
+        // fake source refers to the assignment statement
+        object IndexedAssignmentCoercion : ImplicitUnit()
+    }
 
     // delegates are wrapped into FirWrappedDelegateExpression
     // with a fake sources which refers to delegated expression
diff --git a/compiler/testData/codegen/box/fir/listAssignmentInWhen.kt b/compiler/testData/codegen/box/fir/listAssignmentInWhen.kt
new file mode 100644
index 00000000000..9605876063c
--- /dev/null
+++ b/compiler/testData/codegen/box/fir/listAssignmentInWhen.kt
@@ -0,0 +1,14 @@
+// ISSUE: KT-59748
+// WITH_STDLIB
+
+fun foo(list: MutableList<Any?>, condition: Boolean): Unit = when {
+    condition -> list[0] = "OK"
+    else -> Unit
+}
+
+fun box(): String {
+    val list = mutableListOf<Any?>("FAIL")
+    foo(list, true)
+    foo(list, false)
+    return list[0] as String
+}
diff --git a/compiler/testData/diagnostics/tests/regressions/kt235.fir.kt b/compiler/testData/diagnostics/tests/regressions/kt235.fir.kt
index 1b36e923024..b27af0f7e96 100644
--- a/compiler/testData/diagnostics/tests/regressions/kt235.fir.kt
+++ b/compiler/testData/diagnostics/tests/regressions/kt235.fir.kt
@@ -5,7 +5,7 @@ package kt235
 fun main() {
     val array = MyArray()
     val f: () -> String = <!INITIALIZER_TYPE_MISMATCH!>{
-        <!TYPE_MISMATCH!>array[2] = 23<!> //error: Type mismatch: inferred type is Int (!!!) but String was expected
+        array[2] = 23 //error: Type mismatch: inferred type is Int (!!!) but String was expected
     }<!>
     val g: () -> String = <!INITIALIZER_TYPE_MISMATCH!>{
         var x = 1
@@ -17,11 +17,11 @@ fun main() {
     }<!>
     val array1 = MyArray1()
     val i: () -> String = <!INITIALIZER_TYPE_MISMATCH!>{
-        <!TYPE_MISMATCH!>array1[2] = 23<!>
+        array1[2] = 23
     }<!>
 
     val fi: () -> String = <!INITIALIZER_TYPE_MISMATCH!>{
-        <!TYPE_MISMATCH!>array[2] = 23<!>
+        array[2] = 23
     }<!>
     val gi: () -> String = <!INITIALIZER_TYPE_MISMATCH!>{
         var x = 1
diff --git a/compiler/testData/diagnostics/testsWithJsStdLib/dynamicTypes/setOperatorOnDynamic.fir.txt b/compiler/testData/diagnostics/testsWithJsStdLib/dynamicTypes/setOperatorOnDynamic.fir.txt
index 0780b438129..45d8886b4fa 100644
--- a/compiler/testData/diagnostics/testsWithJsStdLib/dynamicTypes/setOperatorOnDynamic.fir.txt
+++ b/compiler/testData/diagnostics/testsWithJsStdLib/dynamicTypes/setOperatorOnDynamic.fir.txt
@@ -7,6 +7,7 @@ FILE: setOperatorOnDynamic.fir.kt
         )
         lval x3: R|kotlin/Any| = R|kotlin/arrayOf|<R|kotlin/String|>().R|kotlin/collections/fold|<R|kotlin/String|, R|dynamic|>(R|kotlin/js/js|(String(({}))), <L> = fold@fun <anonymous>(res: R|dynamic|, key: R|kotlin/String|): R|dynamic| <inline=Inline, kind=UNKNOWN>  {
             R|<local>/res|.R|<dynamic>/set|(vararg(R|<local>/key|, String(hello)))
+            Unit
             ^ R|<local>/res|
         }
         )
diff --git a/compiler/testData/diagnostics/testsWithStdLib/builderInference/unsafeAssignmentExtra.fir.txt b/compiler/testData/diagnostics/testsWithStdLib/builderInference/unsafeAssignmentExtra.fir.txt
index 080dc258912..09adea5d716 100644
--- a/compiler/testData/diagnostics/testsWithStdLib/builderInference/unsafeAssignmentExtra.fir.txt
+++ b/compiler/testData/diagnostics/testsWithStdLib/builderInference/unsafeAssignmentExtra.fir.txt
@@ -29,6 +29,7 @@ FILE: unsafeAssignmentExtra.fir.kt
     public final fun main(arg: R|kotlin/Any|, condition: R|kotlin/Boolean|): R|kotlin/Unit| {
         lval value: R|Foo<kotlin/Int>| = R|/myBuilder|<R|kotlin/Int|>(<L> = myBuilder@fun R|Foo<kotlin/Int>|.<anonymous>(): R|kotlin/Unit| <inline=NoInline>  {
             this@R|special/anonymous|.R|SubstitutionOverride</Foo.b: R|kotlin/Array<Stub (chain inference): TypeVariable(T)>|>|.R|SubstitutionOverride<kotlin/Array.set: R|kotlin/Unit|>|(Int(0), Int(123))
+            Unit
             this@R|special/anonymous|.R|SubstitutionOverride</Foo.a: R|Stub (chain inference): TypeVariable(T)|>| = Int(45)
              {
                 lval <unary>: R|kotlin/Int| = this@R|special/anonymous|.R|SubstitutionOverride</Foo.a: R|Stub (chain inference): TypeVariable(T)|>|
@@ -103,6 +104,7 @@ FILE: unsafeAssignmentExtra.fir.kt
             this@R|special/anonymous|.R|SubstitutionOverride</Foo.accept: R|kotlin/Unit|>|(String())
             this@R|special/anonymous|.R|SubstitutionOverride</Foo.a: R|Stub (chain inference): TypeVariable(T)|>| = Int(45)
             this@R|special/anonymous|.R|SubstitutionOverride</Foo.b: R|kotlin/Array<Stub (chain inference): TypeVariable(T)>|>|.R|SubstitutionOverride<kotlin/Array.set: R|kotlin/Unit|>|(Int(0), Int(123))
+            Unit
             R|<local>/baz|(this@R|special/anonymous|.R|SubstitutionOverride</Foo.a: R|Stub (chain inference): TypeVariable(T)|>|)
         }
         )
diff --git a/compiler/testData/diagnostics/testsWithStdLib/listAssignmentInWhen.fir.kt b/compiler/testData/diagnostics/testsWithStdLib/listAssignmentInWhen.fir.kt
index 7f3ef54b052..464e0350454 100644
--- a/compiler/testData/diagnostics/testsWithStdLib/listAssignmentInWhen.fir.kt
+++ b/compiler/testData/diagnostics/testsWithStdLib/listAssignmentInWhen.fir.kt
@@ -1,10 +1,10 @@
 // ISSUE: KT-59748
 // FIR_DUMP
 
-fun foo(list: MutableList<Any?>, condition: Boolean): Unit = <!RETURN_TYPE_MISMATCH!>when {
+fun foo(list: MutableList<Any?>, condition: Boolean): Unit = when {
     condition -> list[0] = ""
     else -> Unit
-}<!>
+}
 
 fun bar(list: MutableList<Any?>, condition: Boolean): Unit = <!RETURN_TYPE_MISMATCH!>when {
     condition -> list.set(0, "")
diff --git a/compiler/testData/diagnostics/testsWithStdLib/listAssignmentInWhen.fir.txt b/compiler/testData/diagnostics/testsWithStdLib/listAssignmentInWhen.fir.txt
index 4d682c1ed88..fce42a5e208 100644
--- a/compiler/testData/diagnostics/testsWithStdLib/listAssignmentInWhen.fir.txt
+++ b/compiler/testData/diagnostics/testsWithStdLib/listAssignmentInWhen.fir.txt
@@ -2,7 +2,11 @@ FILE: listAssignmentInWhen.fir.kt
     public final fun foo(list: R|kotlin/collections/MutableList<kotlin/Any?>|, condition: R|kotlin/Boolean|): R|kotlin/Unit| {
         ^foo when () {
             R|<local>/condition| ->  {
-                R|<local>/list|.R|SubstitutionOverride<kotlin/collections/MutableList.set: R|kotlin/Any?|>|(Int(0), String())
+                 {
+                    R|<local>/list|.R|SubstitutionOverride<kotlin/collections/MutableList.set: R|kotlin/Any?|>|(Int(0), String())
+                    Unit
+                }
+
             }
             else ->  {
                 Q|kotlin/Unit|
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 722aed0a7f7..f6634f416de 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
@@ -17711,6 +17711,12 @@ public class BlackBoxCodegenTestGenerated extends AbstractBlackBoxCodegenTest {
             runTest("compiler/testData/codegen/box/fir/KotlinDocumentationProvider.kt");
         }
 
+        @Test
+        @TestMetadata("listAssignmentInWhen.kt")
+        public void testListAssignmentInWhen() throws Exception {
+            runTest("compiler/testData/codegen/box/fir/listAssignmentInWhen.kt");
+        }
+
         @Test
         @TestMetadata("localInvokeExtension.kt")
         public void testLocalInvokeExtension() 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 77cf894b725..15787873ecf 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
@@ -18587,6 +18587,12 @@ public class IrBlackBoxCodegenTestGenerated extends AbstractIrBlackBoxCodegenTes
             runTest("compiler/testData/codegen/box/fir/linkViaSignatures.kt");
         }
 
+        @Test
+        @TestMetadata("listAssignmentInWhen.kt")
+        public void testListAssignmentInWhen() throws Exception {
+            runTest("compiler/testData/codegen/box/fir/listAssignmentInWhen.kt");
+        }
+
         @Test
         @TestMetadata("localInvokeExtension.kt")
         public void testLocalInvokeExtension() throws Exception {
diff --git a/compiler/tests-common-new/tests-gen/org/jetbrains/kotlin/test/runners/codegen/IrBlackBoxCodegenWithIrInlinerTestGenerated.java b/compiler/tests-common-new/tests-gen/org/jetbrains/kotlin/test/runners/codegen/IrBlackBoxCodegenWithIrInlinerTestGenerated.java
index f9aba070ea5..a3e88d8c6ec 100644
--- a/compiler/tests-common-new/tests-gen/org/jetbrains/kotlin/test/runners/codegen/IrBlackBoxCodegenWithIrInlinerTestGenerated.java
+++ b/compiler/tests-common-new/tests-gen/org/jetbrains/kotlin/test/runners/codegen/IrBlackBoxCodegenWithIrInlinerTestGenerated.java
@@ -18587,6 +18587,12 @@ public class IrBlackBoxCodegenWithIrInlinerTestGenerated extends AbstractIrBlack
             runTest("compiler/testData/codegen/box/fir/linkViaSignatures.kt");
         }
 
+        @Test
+        @TestMetadata("listAssignmentInWhen.kt")
+        public void testListAssignmentInWhen() throws Exception {
+            runTest("compiler/testData/codegen/box/fir/listAssignmentInWhen.kt");
+        }
+
         @Test
         @TestMetadata("localInvokeExtension.kt")
         public void testLocalInvokeExtension() 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 002eeebedc2..a8993e246d6 100644
--- a/compiler/tests-gen/org/jetbrains/kotlin/codegen/LightAnalysisModeTestGenerated.java
+++ b/compiler/tests-gen/org/jetbrains/kotlin/codegen/LightAnalysisModeTestGenerated.java
@@ -15440,6 +15440,11 @@ public class LightAnalysisModeTestGenerated extends AbstractLightAnalysisModeTes
             runTest("compiler/testData/codegen/box/fir/linkViaSignatures.kt");
         }
 
+        @TestMetadata("listAssignmentInWhen.kt")
+        public void testListAssignmentInWhen() throws Exception {
+            runTest("compiler/testData/codegen/box/fir/listAssignmentInWhen.kt");
+        }
+
         @TestMetadata("localInvokeExtension.kt")
         public void testLocalInvokeExtension() throws Exception {
             runTest("compiler/testData/codegen/box/fir/localInvokeExtension.kt");
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 215bff5fa34..888c16b58f2 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
@@ -13679,6 +13679,12 @@ public class FirJsCodegenBoxTestGenerated extends AbstractFirJsCodegenBoxTest {
             runTest("compiler/testData/codegen/box/fir/falsePositiveBoundSmartcast.kt");
         }
 
+        @Test
+        @TestMetadata("listAssignmentInWhen.kt")
+        public void testListAssignmentInWhen() throws Exception {
+            runTest("compiler/testData/codegen/box/fir/listAssignmentInWhen.kt");
+        }
+
         @Test
         @TestMetadata("localInvokeExtension.kt")
         public void testLocalInvokeExtension() 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 8a4290099dc..5ff2b8e437f 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
@@ -13679,6 +13679,12 @@ public class IrJsCodegenBoxTestGenerated extends AbstractIrJsCodegenBoxTest {
             runTest("compiler/testData/codegen/box/fir/falsePositiveBoundSmartcast.kt");
         }
 
+        @Test
+        @TestMetadata("listAssignmentInWhen.kt")
+        public void testListAssignmentInWhen() throws Exception {
+            runTest("compiler/testData/codegen/box/fir/listAssignmentInWhen.kt");
+        }
+
         @Test
         @TestMetadata("localInvokeExtension.kt")
         public void testLocalInvokeExtension() throws Exception {
diff --git a/js/js.tests/tests-gen/org/jetbrains/kotlin/js/test/ir/IrJsES6CodegenBoxTestGenerated.java b/js/js.tests/tests-gen/org/jetbrains/kotlin/js/test/ir/IrJsES6CodegenBoxTestGenerated.java
index d6d2e59b765..35d00bdec41 100644
--- a/js/js.tests/tests-gen/org/jetbrains/kotlin/js/test/ir/IrJsES6CodegenBoxTestGenerated.java
+++ b/js/js.tests/tests-gen/org/jetbrains/kotlin/js/test/ir/IrJsES6CodegenBoxTestGenerated.java
@@ -13679,6 +13679,12 @@ public class IrJsES6CodegenBoxTestGenerated extends AbstractIrJsES6CodegenBoxTes
             runTest("compiler/testData/codegen/box/fir/falsePositiveBoundSmartcast.kt");
         }
 
+        @Test
+        @TestMetadata("listAssignmentInWhen.kt")
+        public void testListAssignmentInWhen() throws Exception {
+            runTest("compiler/testData/codegen/box/fir/listAssignmentInWhen.kt");
+        }
+
         @Test
         @TestMetadata("localInvokeExtension.kt")
         public void testLocalInvokeExtension() throws Exception {
diff --git a/native/native.tests/tests-gen/org/jetbrains/kotlin/konan/blackboxtest/FirNativeCodegenBoxTestGenerated.java b/native/native.tests/tests-gen/org/jetbrains/kotlin/konan/blackboxtest/FirNativeCodegenBoxTestGenerated.java
index ab172c9cde9..c8fb3b22f0c 100644
--- a/native/native.tests/tests-gen/org/jetbrains/kotlin/konan/blackboxtest/FirNativeCodegenBoxTestGenerated.java
+++ b/native/native.tests/tests-gen/org/jetbrains/kotlin/konan/blackboxtest/FirNativeCodegenBoxTestGenerated.java
@@ -14785,6 +14785,12 @@ public class FirNativeCodegenBoxTestGenerated extends AbstractNativeCodegenBoxTe
                 runTest("compiler/testData/codegen/box/fir/falsePositiveBoundSmartcast.kt");
             }
 
+            @Test
+            @TestMetadata("listAssignmentInWhen.kt")
+            public void testListAssignmentInWhen() throws Exception {
+                runTest("compiler/testData/codegen/box/fir/listAssignmentInWhen.kt");
+            }
+
             @Test
             @TestMetadata("localInvokeExtension.kt")
             public void testLocalInvokeExtension() throws Exception {
diff --git a/native/native.tests/tests-gen/org/jetbrains/kotlin/konan/blackboxtest/FirNativeCodegenBoxTestNoPLGenerated.java b/native/native.tests/tests-gen/org/jetbrains/kotlin/konan/blackboxtest/FirNativeCodegenBoxTestNoPLGenerated.java
index 49847022784..08828f930ef 100644
--- a/native/native.tests/tests-gen/org/jetbrains/kotlin/konan/blackboxtest/FirNativeCodegenBoxTestNoPLGenerated.java
+++ b/native/native.tests/tests-gen/org/jetbrains/kotlin/konan/blackboxtest/FirNativeCodegenBoxTestNoPLGenerated.java
@@ -15133,6 +15133,12 @@ public class FirNativeCodegenBoxTestNoPLGenerated extends AbstractNativeCodegenB
                 runTest("compiler/testData/codegen/box/fir/falsePositiveBoundSmartcast.kt");
             }
 
+            @Test
+            @TestMetadata("listAssignmentInWhen.kt")
+            public void testListAssignmentInWhen() throws Exception {
+                runTest("compiler/testData/codegen/box/fir/listAssignmentInWhen.kt");
+            }
+
             @Test
             @TestMetadata("localInvokeExtension.kt")
             public void testLocalInvokeExtension() throws Exception {
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 1d43c21ffd9..fb248c740cc 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
@@ -14612,6 +14612,12 @@ public class NativeCodegenBoxTestGenerated extends AbstractNativeCodegenBoxTest
                 runTest("compiler/testData/codegen/box/fir/falsePositiveBoundSmartcast.kt");
             }
 
+            @Test
+            @TestMetadata("listAssignmentInWhen.kt")
+            public void testListAssignmentInWhen() throws Exception {
+                runTest("compiler/testData/codegen/box/fir/listAssignmentInWhen.kt");
+            }
+
             @Test
             @TestMetadata("localInvokeExtension.kt")
             public void testLocalInvokeExtension() throws Exception {
diff --git a/native/native.tests/tests-gen/org/jetbrains/kotlin/konan/blackboxtest/NativeCodegenBoxTestNoPLGenerated.java b/native/native.tests/tests-gen/org/jetbrains/kotlin/konan/blackboxtest/NativeCodegenBoxTestNoPLGenerated.java
index 22d43f224a5..9c1e9d6973a 100644
--- a/native/native.tests/tests-gen/org/jetbrains/kotlin/konan/blackboxtest/NativeCodegenBoxTestNoPLGenerated.java
+++ b/native/native.tests/tests-gen/org/jetbrains/kotlin/konan/blackboxtest/NativeCodegenBoxTestNoPLGenerated.java
@@ -14786,6 +14786,12 @@ public class NativeCodegenBoxTestNoPLGenerated extends AbstractNativeCodegenBoxT
                 runTest("compiler/testData/codegen/box/fir/falsePositiveBoundSmartcast.kt");
             }
 
+            @Test
+            @TestMetadata("listAssignmentInWhen.kt")
+            public void testListAssignmentInWhen() throws Exception {
+                runTest("compiler/testData/codegen/box/fir/listAssignmentInWhen.kt");
+            }
+
             @Test
             @TestMetadata("localInvokeExtension.kt")
             public void testLocalInvokeExtension() throws Exception {
diff --git a/wasm/wasm.tests/tests-gen/org/jetbrains/kotlin/wasm/test/FirWasmCodegenBoxTestGenerated.java b/wasm/wasm.tests/tests-gen/org/jetbrains/kotlin/wasm/test/FirWasmCodegenBoxTestGenerated.java
index 45d7580d319..864933919b1 100644
--- a/wasm/wasm.tests/tests-gen/org/jetbrains/kotlin/wasm/test/FirWasmCodegenBoxTestGenerated.java
+++ b/wasm/wasm.tests/tests-gen/org/jetbrains/kotlin/wasm/test/FirWasmCodegenBoxTestGenerated.java
@@ -13655,6 +13655,12 @@ public class FirWasmCodegenBoxTestGenerated extends AbstractFirWasmCodegenBoxTes
             runTest("compiler/testData/codegen/box/fir/falsePositiveBoundSmartcast.kt");
         }
 
+        @Test
+        @TestMetadata("listAssignmentInWhen.kt")
+        public void testListAssignmentInWhen() throws Exception {
+            runTest("compiler/testData/codegen/box/fir/listAssignmentInWhen.kt");
+        }
+
         @Test
         @TestMetadata("localInvokeExtension.kt")
         public void testLocalInvokeExtension() throws Exception {
diff --git a/wasm/wasm.tests/tests-gen/org/jetbrains/kotlin/wasm/test/K1WasmCodegenBoxTestGenerated.java b/wasm/wasm.tests/tests-gen/org/jetbrains/kotlin/wasm/test/K1WasmCodegenBoxTestGenerated.java
index 9d8c0041dec..b00751657f1 100644
--- a/wasm/wasm.tests/tests-gen/org/jetbrains/kotlin/wasm/test/K1WasmCodegenBoxTestGenerated.java
+++ b/wasm/wasm.tests/tests-gen/org/jetbrains/kotlin/wasm/test/K1WasmCodegenBoxTestGenerated.java
@@ -13655,6 +13655,12 @@ public class K1WasmCodegenBoxTestGenerated extends AbstractK1WasmCodegenBoxTest
             runTest("compiler/testData/codegen/box/fir/falsePositiveBoundSmartcast.kt");
         }
 
+        @Test
+        @TestMetadata("listAssignmentInWhen.kt")
+        public void testListAssignmentInWhen() throws Exception {
+            runTest("compiler/testData/codegen/box/fir/listAssignmentInWhen.kt");
+        }
+
         @Test
         @TestMetadata("localInvokeExtension.kt")
         public void testLocalInvokeExtension() throws Exception {