diff --git a/compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/interpreter/IrInterpreter.kt b/compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/interpreter/IrInterpreter.kt
index 19f1e910e27..4add67c5f30 100644
--- a/compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/interpreter/IrInterpreter.kt
+++ b/compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/interpreter/IrInterpreter.kt
@@ -59,7 +59,7 @@ class IrInterpreter(irModule: IrModuleFragment, private val bodyMap: Map<IdSigna
             is Double -> irBuiltIns.doubleType
             null -> irBuiltIns.nothingType
             else -> when (defaultType.classifierOrNull?.owner) {
-                is IrTypeParameter -> stack.getVariableState(defaultType.classifierOrFail.descriptor).irClass.defaultType
+                is IrTypeParameter -> stack.getVariable(defaultType.classifierOrFail.descriptor).state.irClass.defaultType
                 else -> defaultType
             }
         }
@@ -284,7 +284,7 @@ class IrInterpreter(irModule: IrModuleFragment, private val bodyMap: Map<IdSigna
 
         interpretValueParameters(expression, irFunction, valueArguments).check { return it }
 
-        valueArguments.addAll(getTypeArguments(irFunction, expression) { stack.getVariableState(it) })
+        valueArguments.addAll(getTypeArguments(irFunction, expression) { stack.getVariable(it).state })
         if (dispatchReceiver is Complex) valueArguments.addAll(dispatchReceiver.typeArguments)
         if (extensionReceiver is Complex) valueArguments.addAll(extensionReceiver.typeArguments)
 
@@ -331,9 +331,9 @@ class IrInterpreter(irModule: IrModuleFragment, private val bodyMap: Map<IdSigna
             property.backingField?.initializer?.expression?.interpret()?.check { return it }
             val receiver = irClass.descriptor.thisAsReceiverParameter
             if (property.backingField?.initializer != null) {
-                val receiverState = stack.getVariableState(receiver)
-                val propertyState = Variable(property.backingField!!.descriptor, stack.popReturnValue())
-                receiverState.setState(propertyState)
+                val receiverState = stack.getVariable(receiver).state
+                val property = Variable(property.backingField!!.descriptor, stack.popReturnValue())
+                receiverState.setField(property)
             }
         }
 
@@ -351,7 +351,7 @@ class IrInterpreter(irModule: IrModuleFragment, private val bodyMap: Map<IdSigna
         interpretValueParameters(constructorCall, owner, valueArguments).check { return it }
 
         val irClass = owner.parent as IrClass
-        val typeArguments = getTypeArguments(irClass, constructorCall) { stack.getVariableState(it) }
+        val typeArguments = getTypeArguments(irClass, constructorCall) { stack.getVariable(it).state }
         if (irClass.hasAnnotation(evaluateIntrinsicAnnotation) || irClass.fqNameWhenAvailable!!.startsWith(Name.identifier("java"))) {
             return stack.newFrame(initPool = valueArguments) { Wrapper.getConstructorMethod(owner).invokeMethod(owner) }
                 .apply { (stack.peekReturnValue() as? Wrapper)?.typeArguments?.addAll(typeArguments) } // 'as?' because can be exception
@@ -502,14 +502,14 @@ class IrInterpreter(irModule: IrModuleFragment, private val bodyMap: Map<IdSigna
 
         // receiver is null only for top level var, but it cannot be used in constexpr; corresponding check is on frontend
         val receiver = (expression.receiver as IrDeclarationReference).symbol.descriptor
-        stack.getVariableState(receiver).setState(Variable(expression.symbol.owner.descriptor, stack.popReturnValue()))
+        stack.getVariable(receiver).apply { this.state.setField(Variable(expression.symbol.owner.descriptor, stack.popReturnValue())) }
         return Next
     }
 
     private suspend fun interpretGetField(expression: IrGetField): ExecutionResult {
         val receiver = (expression.receiver as? IrDeclarationReference)?.symbol?.descriptor
         // receiver is null, for example, for top level fields
-        val result = receiver?.let { stack.getVariableState(receiver).getState(expression.symbol.descriptor)?.copy() }
+        val result = receiver?.let { stack.getVariable(receiver).state.getState(expression.symbol.descriptor) }
             ?: return (expression.symbol.owner.initializer?.expression?.interpret() ?: Next)
         stack.pushReturnValue(result)
         return Next
@@ -519,7 +519,7 @@ class IrInterpreter(irModule: IrModuleFragment, private val bodyMap: Map<IdSigna
         val owner = expression.type.classOrNull?.owner
         // used to evaluate constants inside object
         if (owner != null && owner.isObject) return getOrCreateObjectValue(owner) // TODO is this correct behaviour?
-        stack.pushReturnValue(stack.getVariableState(expression.symbol.descriptor).copy())
+        stack.pushReturnValue(stack.getVariable(expression.symbol.descriptor).state)
         return Next
     }
 
@@ -533,8 +533,7 @@ class IrInterpreter(irModule: IrModuleFragment, private val bodyMap: Map<IdSigna
         expression.value.interpret().check { return it }
 
         if (stack.contains(expression.symbol.descriptor)) {
-            val variable = stack.getVariableState(expression.symbol.descriptor)
-            variable.setState(Variable(expression.symbol.descriptor, stack.popReturnValue()))
+            stack.getVariable(expression.symbol.descriptor).apply { this.state = stack.popReturnValue() }
         } else {
             stack.addVar(Variable(expression.symbol.descriptor, stack.popReturnValue()))
         }
@@ -600,7 +599,7 @@ class IrInterpreter(irModule: IrModuleFragment, private val bodyMap: Map<IdSigna
     private suspend fun interpretTypeOperatorCall(expression: IrTypeOperatorCall): ExecutionResult {
         val executionResult = expression.argument.interpret().check { return it }
         val typeOperandDescriptor = expression.typeOperand.classifierOrFail.descriptor
-        val typeOperandClass = expression.typeOperand.classOrNull?.owner ?: stack.getVariableState(typeOperandDescriptor).irClass
+        val typeOperandClass = expression.typeOperand.classOrNull?.owner ?: stack.getVariable(typeOperandDescriptor).state.irClass
 
         when (expression.operator) {
             // coercion to unit means that return value isn't used
diff --git a/compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/interpreter/intrinsics/IntrinsicImplementations.kt b/compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/interpreter/intrinsics/IntrinsicImplementations.kt
index f5c30f23d00..feea363ae81 100644
--- a/compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/interpreter/intrinsics/IntrinsicImplementations.kt
+++ b/compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/interpreter/intrinsics/IntrinsicImplementations.kt
@@ -60,7 +60,7 @@ object ArrayOfNulls : IntrinsicBase() {
     override suspend fun evaluate(
         irFunction: IrFunction, stack: Stack, interpret: suspend IrElement.() -> ExecutionResult
     ): ExecutionResult {
-        val size = stack.getVariableState(irFunction.valueParameters.first().descriptor).asInt()
+        val size = stack.getVariable(irFunction.valueParameters.first().descriptor).state.asInt()
         val array = arrayOfNulls<Any?>(size)
         stack.pushReturnValue(array.toState(irFunction.returnType))
         return Next
@@ -77,7 +77,7 @@ object EnumValues : IntrinsicBase() {
         irFunction: IrFunction, stack: Stack, interpret: suspend IrElement.() -> ExecutionResult
     ): ExecutionResult {
         val enumClass = when (irFunction.fqNameWhenAvailable.toString()) {
-            "kotlin.enumValues" -> stack.getVariableState(irFunction.typeParameters.first().descriptor).irClass
+            "kotlin.enumValues" -> stack.getVariable(irFunction.typeParameters.first().descriptor).state.irClass
             else -> irFunction.parent as IrClass
         }
 
@@ -98,10 +98,10 @@ object EnumValueOf : IntrinsicBase() {
         irFunction: IrFunction, stack: Stack, interpret: suspend IrElement.() -> ExecutionResult
     ): ExecutionResult {
         val enumClass = when (irFunction.fqNameWhenAvailable.toString()) {
-            "kotlin.enumValueOf" -> stack.getVariableState(irFunction.typeParameters.first().descriptor).irClass
+            "kotlin.enumValueOf" -> stack.getVariable(irFunction.typeParameters.first().descriptor).state.irClass
             else -> irFunction.parent as IrClass
         }
-        val enumEntryName = stack.getVariableState(irFunction.valueParameters.first().descriptor).asString()
+        val enumEntryName = stack.getVariable(irFunction.valueParameters.first().descriptor).state.asString()
         val enumEntry = enumClass.declarations.filterIsInstance<IrEnumEntry>().singleOrNull { it.name.asString() == enumEntryName }
         enumEntry?.interpret()?.check { return it }
             ?: throw IllegalArgumentException("No enum constant ${enumClass.fqNameWhenAvailable}.$enumEntryName")
@@ -160,12 +160,12 @@ object JsPrimitives : IntrinsicBase() {
     ): ExecutionResult {
         when (irFunction.fqNameWhenAvailable.toString()) {
             "kotlin.Long.<init>" -> {
-                val low = stack.getVariableState(irFunction.valueParameters[0].descriptor).asInt()
-                val high = stack.getVariableState(irFunction.valueParameters[1].descriptor).asInt()
+                val low = stack.getVariable(irFunction.valueParameters[0].descriptor).state.asInt()
+                val high = stack.getVariable(irFunction.valueParameters[1].descriptor).state.asInt()
                 stack.pushReturnValue((high.toLong().shl(32) + low).toState(irFunction.returnType))
             }
             "kotlin.Char.<init>" -> {
-                val value = stack.getVariableState(irFunction.valueParameters[0].descriptor).asInt()
+                val value = stack.getVariable(irFunction.valueParameters[0].descriptor).state.asInt()
                 stack.pushReturnValue(value.toChar().toState(irFunction.returnType))
             }
         }
@@ -183,12 +183,12 @@ object ArrayConstructor : IntrinsicBase() {
         irFunction: IrFunction, stack: Stack, interpret: suspend IrElement.() -> ExecutionResult
     ): ExecutionResult {
         val sizeDescriptor = irFunction.valueParameters[0].descriptor
-        val size = stack.getVariableState(sizeDescriptor).asInt()
+        val size = stack.getVariable(sizeDescriptor).state.asInt()
         val arrayValue = MutableList<Any>(size) { 0 }
 
         if (irFunction.valueParameters.size == 2) {
             val initDescriptor = irFunction.valueParameters[1].descriptor
-            val initLambda = stack.getVariableState(initDescriptor) as Lambda
+            val initLambda = stack.getVariable(initDescriptor).state as Lambda
             val index = initLambda.irFunction.valueParameters.single()
             for (i in 0 until size) {
                 val indexVar = listOf(Variable(index.descriptor, i.toState(index.type)))
diff --git a/compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/interpreter/stack/Frame.kt b/compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/interpreter/stack/Frame.kt
index 787d0bce72d..5e21096e8e8 100644
--- a/compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/interpreter/stack/Frame.kt
+++ b/compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/interpreter/stack/Frame.kt
@@ -14,8 +14,7 @@ import kotlin.NoSuchElementException
 interface Frame {
     fun addVar(variable: Variable)
     fun addAll(variables: List<Variable>)
-    fun getVariableState(variableDescriptor: DeclarationDescriptor): State
-    fun tryGetVariableState(variableDescriptor: DeclarationDescriptor): State?
+    fun getVariable(variableDescriptor: DeclarationDescriptor): Variable?
     fun getAll(): List<Variable>
     fun contains(descriptor: DeclarationDescriptor): Boolean
     fun pushReturnValue(state: State)
@@ -40,14 +39,9 @@ class InterpreterFrame(
         pool.addAll(variables)
     }
 
-    override fun tryGetVariableState(variableDescriptor: DeclarationDescriptor): State? {
+    override fun getVariable(variableDescriptor: DeclarationDescriptor): Variable? {
         return (if (variableDescriptor is TypeParameterDescriptor) typeArguments else pool)
-            .firstOrNull { it.descriptor.equalTo(variableDescriptor) }?.state
-    }
-
-    override fun getVariableState(variableDescriptor: DeclarationDescriptor): State {
-        return tryGetVariableState(variableDescriptor)
-            ?: throw NoSuchElementException("Frame pool doesn't contains variable with descriptor $variableDescriptor")
+            .firstOrNull { it.descriptor.equalTo(variableDescriptor) }
     }
 
     override fun getAll(): List<Variable> {
diff --git a/compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/interpreter/stack/Stack.kt b/compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/interpreter/stack/Stack.kt
index fbd737d629e..04e657c97b0 100644
--- a/compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/interpreter/stack/Stack.kt
+++ b/compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/interpreter/stack/Stack.kt
@@ -28,7 +28,7 @@ interface Stack {
     fun clean()
     fun addVar(variable: Variable)
     fun addAll(variables: List<Variable>)
-    fun getVariableState(variableDescriptor: DeclarationDescriptor): State
+    fun getVariable(variableDescriptor: DeclarationDescriptor): Variable
     fun getAll(): List<Variable>
 
     fun contains(descriptor: DeclarationDescriptor): Boolean
@@ -86,8 +86,8 @@ class StackImpl : Stack {
         getCurrentFrame().addAll(variables)
     }
 
-    override fun getVariableState(variableDescriptor: DeclarationDescriptor): State {
-        return getCurrentFrame().getVariableState(variableDescriptor)
+    override fun getVariable(variableDescriptor: DeclarationDescriptor): Variable {
+        return getCurrentFrame().getVariable(variableDescriptor)
     }
 
     override fun getAll(): List<Variable> {
@@ -132,8 +132,8 @@ private class FrameContainer(current: Frame = InterpreterFrame()) {
     fun addVar(variable: Variable) = getTopFrame().addVar(variable)
     fun addAll(variables: List<Variable>) = getTopFrame().addAll(variables)
     fun getAll() = innerStack.flatMap { it.getAll() }
-    fun getVariableState(variableDescriptor: DeclarationDescriptor): State {
-        return innerStack.firstNotNullResult { it.tryGetVariableState(variableDescriptor) }
+    fun getVariable(variableDescriptor: DeclarationDescriptor): Variable {
+        return innerStack.firstNotNullResult { it.getVariable(variableDescriptor) }
             ?: throw InterpreterException("$variableDescriptor not found") // TODO better message
     }
 
diff --git a/compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/interpreter/stack/Variable.kt b/compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/interpreter/stack/Variable.kt
index 50d7ea7a9b4..28514d0ca0a 100644
--- a/compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/interpreter/stack/Variable.kt
+++ b/compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/interpreter/stack/Variable.kt
@@ -9,7 +9,7 @@ import org.jetbrains.kotlin.backend.common.interpreter.state.State
 import org.jetbrains.kotlin.descriptors.DeclarationDescriptor
 import org.jetbrains.kotlin.descriptors.ReceiverParameterDescriptor
 
-data class Variable(val descriptor: DeclarationDescriptor, val state: State) {
+data class Variable(val descriptor: DeclarationDescriptor, var state: State) {
     override fun toString(): String {
         val descriptorName = when (descriptor) {
             is ReceiverParameterDescriptor -> descriptor.containingDeclaration.name.toString() + "::this"
diff --git a/compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/interpreter/state/Common.kt b/compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/interpreter/state/Common.kt
index 3fa4490e590..16c575291cc 100644
--- a/compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/interpreter/state/Common.kt
+++ b/compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/interpreter/state/Common.kt
@@ -48,8 +48,6 @@ class Common private constructor(
             .let { getOverridden(it as IrSimpleFunction, this) }
     }
 
-    override fun copy() = Common(irClass, fields).copyFrom(this)
-
     override fun toString(): String {
         return "Common(obj='${irClass.fqNameForIrSerialization}', super=$superClass, values=$fields)"
     }
diff --git a/compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/interpreter/state/Complex.kt b/compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/interpreter/state/Complex.kt
index a81d7ecacee..3abe4bd9736 100644
--- a/compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/interpreter/state/Complex.kt
+++ b/compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/interpreter/state/Complex.kt
@@ -21,6 +21,7 @@ import org.jetbrains.kotlin.ir.util.isInterface
 abstract class Complex(override val irClass: IrClass, override val fields: MutableList<Variable>) : State {
     var superClass: Complex? = null
     var subClass: Complex? = null
+    val interfaces: MutableList<Complex> = mutableListOf() // filled lazily, as needed
     val typeArguments: MutableList<Variable> = mutableListOf()
     var outerClass: Variable? = null
 
@@ -46,21 +47,6 @@ abstract class Complex(override val irClass: IrClass, override val fields: Mutab
 
     private fun contains(variable: Variable) = fields.any { it.descriptor == variable.descriptor }
 
-    override fun setState(newVar: Variable) {
-        when (val oldState = fields.firstOrNull { it.descriptor == newVar.descriptor }) {
-            null -> fields.add(newVar)                          // newVar isn't present in value list
-            else -> fields[fields.indexOf(oldState)] = newVar   // newVar already present
-        }
-    }
-
-    protected fun copyFrom(other: Complex): State {
-        this.superClass = other.superClass
-        this.subClass = other.subClass ?: other
-        this.typeArguments.addAll(other.typeArguments)
-        this.outerClass = other.outerClass
-        return this
-    }
-
     private fun getIrFunction(descriptor: FunctionDescriptor): IrFunction? {
         val propertyGetters = irClass.declarations.filterIsInstance<IrProperty>().mapNotNull { it.getter }
         val functions = irClass.declarations.filterIsInstance<IrFunction>()
@@ -70,10 +56,9 @@ abstract class Complex(override val irClass: IrClass, override val fields: Mutab
     private fun getThisOrSuperReceiver(superIrClass: IrClass?): Complex? {
         return when {
             superIrClass == null -> this.getOriginal()
-            superIrClass.isInterface -> {
-                val interfaceState = Common(superIrClass)
-                (this.copy() as Complex).setSuperClassInstance(interfaceState)
-                interfaceState
+            superIrClass.isInterface -> Common(superIrClass).apply {
+                interfaces.add(this)
+                this.subClass = this@Complex
             }
             else -> this.superClass
         }
diff --git a/compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/interpreter/state/ExceptionState.kt b/compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/interpreter/state/ExceptionState.kt
index 63b30b3e8bb..5dbbcefc4d5 100644
--- a/compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/interpreter/state/ExceptionState.kt
+++ b/compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/interpreter/state/ExceptionState.kt
@@ -80,11 +80,11 @@ class ExceptionState private constructor(
     }
 
     private fun setMessage(messageValue: String? = null) {
-        setState(Variable(messageProperty.descriptor, Primitive(messageValue, messageProperty.getter!!.returnType)))
+        setField(Variable(messageProperty.descriptor, Primitive(messageValue, messageProperty.getter!!.returnType)))
     }
 
     private fun setCause(causeValue: State?) {
-        setState(Variable(causeProperty.descriptor, causeValue ?: Primitive<Throwable?>(null, causeProperty.getter!!.returnType)))
+        setField(Variable(causeProperty.descriptor, causeValue ?: Primitive<Throwable?>(null, causeProperty.getter!!.returnType)))
     }
 
     fun getMessage(): Primitive<String?> = getState(messageProperty.descriptor) as Primitive<String?>
@@ -105,8 +105,6 @@ class ExceptionState private constructor(
 
     fun getThisAsCauseForException() = ExceptionData(this)
 
-    override fun copy() = ExceptionState(irClass, fields, stackTrace).copyFrom(this)
-
     companion object {
         private fun IrClass.getPropertyByName(name: String): IrProperty {
             val getPropertyFun = this.declarations.firstOrNull { it.nameForIrSerialization.asString().contains("get-$name") }
diff --git a/compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/interpreter/state/Lambda.kt b/compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/interpreter/state/Lambda.kt
index cc1d42259ce..0cfcd7c07fb 100644
--- a/compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/interpreter/state/Lambda.kt
+++ b/compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/interpreter/state/Lambda.kt
@@ -19,18 +19,10 @@ class Lambda(val irFunction: IrFunction, override val irClass: IrClass) : State
     // irFunction is anonymous declaration, but irCall will contain descriptor of invoke method from Function interface
     private val invokeDescriptor = irClass.declarations.single { it.nameForIrSerialization.asString() == "invoke" }.descriptor
 
-    override fun setState(newVar: Variable) {
-        throw UnsupportedOperationException("Method setState is not supported in Lambda class")
-    }
-
     override fun getIrFunctionByIrCall(expression: IrCall): IrFunction? {
         return if (invokeDescriptor.equalTo(expression.symbol.descriptor)) irFunction else null
     }
 
-    override fun copy(): State {
-        return Lambda(irFunction, irClass).apply { this.fields.addAll(this@Lambda.fields) }
-    }
-
     override fun toString(): String {
         val receiver = (irFunction.dispatchReceiverParameter?.type ?: irFunction.extensionReceiverParameter?.type)?.getFqName(true)
         val arguments = irFunction.valueParameters.map { it.type.getFqName(true) }.joinToString(prefix = "(", postfix = ")")
diff --git a/compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/interpreter/state/Primitive.kt b/compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/interpreter/state/Primitive.kt
index 66465e7e472..52fd5484701 100644
--- a/compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/interpreter/state/Primitive.kt
+++ b/compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/interpreter/state/Primitive.kt
@@ -24,15 +24,6 @@ class Primitive<T>(var value: T, val type: IrType) : State {
         return super.getState(descriptor) ?: this
     }
 
-    override fun setState(newVar: Variable) {
-        newVar.state as? Primitive<T> ?: throw IllegalArgumentException("Cannot set $newVar in current $this")
-        value = newVar.state.value
-    }
-
-    override fun copy(): State {
-        return Primitive(value, type)
-    }
-
     override fun getIrFunctionByIrCall(expression: IrCall): IrFunction? {
         val descriptor = expression.symbol.descriptor
         // must add property's getter to declaration's list because they are not present in ir class for primitives
diff --git a/compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/interpreter/state/State.kt b/compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/interpreter/state/State.kt
index 0e8b44f3e35..71aa8924d07 100644
--- a/compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/interpreter/state/State.kt
+++ b/compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/interpreter/state/State.kt
@@ -20,16 +20,12 @@ interface State {
         return fields.firstOrNull { it.descriptor.equalTo(descriptor) }?.state
     }
 
-    fun setState(newVar: Variable)
-
-    /**
-     * This method is used for passing a copy of a state.
-     * It is necessary then copy change its state's value, but the original one must remain the same.
-     *
-     * @see copyReceivedValue.kt
-     * @see tryFinally.kt
-     */
-    fun copy(): State
+    fun setField(newVar: Variable) {
+        when (val oldState = fields.firstOrNull { it.descriptor == newVar.descriptor }) {
+            null -> fields.add(newVar)                                      // newVar isn't present in value list
+            else -> fields[fields.indexOf(oldState)].state = newVar.state   // newVar already present
+        }
+    }
 
     fun getIrFunctionByIrCall(expression: IrCall): IrFunction?
 }
diff --git a/compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/interpreter/state/Wrapper.kt b/compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/interpreter/state/Wrapper.kt
index 8ed4d3b168d..e77958c5ae6 100644
--- a/compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/interpreter/state/Wrapper.kt
+++ b/compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/interpreter/state/Wrapper.kt
@@ -52,10 +52,6 @@ class Wrapper(val value: Any, override val irClass: IrClass) : Complex(irClass,
         return MethodHandles.lookup().findVirtual(receiverClass, methodName, methodType)
     }
 
-    override fun setState(newVar: Variable) {
-        throw UnsupportedOperationException("Method setState is not supported in Wrapper class")
-    }
-
     // this method is used to get correct java method name
     // for example: - method 'get' in kotlin StringBuilder is actually 'charAt' in java StringBuilder
     //              - method 'keys' in kotlin Map is actually 'keySet' in java
@@ -194,8 +190,6 @@ class Wrapper(val value: Any, override val irClass: IrClass) : Complex(irClass,
         }
     }
 
-    override fun copy() = Wrapper(value, irClass).copyFrom(this)
-
     override fun toString(): String {
         return "Wrapper(obj='$typeFqName', value=$value)"
     }