diff --git a/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/expressions/IrTypeOperatorCall.kt b/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/expressions/IrTypeOperatorCall.kt
index 99d784da3b6..f23ff69a9fe 100644
--- a/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/expressions/IrTypeOperatorCall.kt
+++ b/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/expressions/IrTypeOperatorCall.kt
@@ -69,6 +69,6 @@ enum class IrTypeOperator {
 abstract class IrTypeOperatorCall : IrExpression() {
     abstract val operator: IrTypeOperator
     abstract var argument: IrExpression
-    abstract val typeOperand: IrType
+    abstract var typeOperand: IrType
     abstract val typeOperandClassifier: IrClassifierSymbol
 }
diff --git a/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/expressions/impl/IrTypeOperatorCallImpl.kt b/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/expressions/impl/IrTypeOperatorCallImpl.kt
index 624632301fd..3f12c0a8e82 100644
--- a/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/expressions/impl/IrTypeOperatorCallImpl.kt
+++ b/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/expressions/impl/IrTypeOperatorCallImpl.kt
@@ -30,7 +30,7 @@ class IrTypeOperatorCallImpl(
     override val endOffset: Int,
     override var type: IrType,
     override val operator: IrTypeOperator,
-    override val typeOperand: IrType,
+    override var typeOperand: IrType,
     override var argument: IrExpression,
 ) : IrTypeOperatorCall() {
     override val typeOperandClassifier: IrClassifierSymbol