diff --git a/compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/interpreter/Label.kt b/compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/interpreter/Label.kt
index 656ab2770ca..8ae9600ee86 100644
--- a/compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/interpreter/Label.kt
+++ b/compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/interpreter/Label.kt
@@ -37,7 +37,10 @@ inline fun ExecutionResult.check(toCheckLabel: ReturnLabel = ReturnLabel.NEXT, r
     return this
 }
 
-fun ExecutionResult.implicitCastIfNeeded(expectedType: IrType, actualType: IrType, stack: Stack): ExecutionResult {
+/**
+ * This method is analog of `checkcast` jvm bytecode operation. Throw exception whenever actual type is not a subtype of expected.
+ */
+internal fun ExecutionResult.implicitCastIfNeeded(expectedType: IrType, actualType: IrType, stack: Stack): ExecutionResult {
     if (actualType.classifierOrNull !is IrTypeParameterSymbol) return this
 
     if (expectedType.classifierOrFail is IrTypeParameterSymbol) return this
diff --git a/compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/interpreter/Utils.kt b/compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/interpreter/Utils.kt
index 3ad85afdf8b..210de640b89 100644
--- a/compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/interpreter/Utils.kt
+++ b/compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/interpreter/Utils.kt
@@ -23,23 +23,15 @@ import org.jetbrains.kotlin.name.FqName
 import org.jetbrains.kotlin.name.Name
 import org.jetbrains.kotlin.utils.addToStdlib.safeAs
 
-fun IrFunction.getDispatchReceiver(): IrValueParameterSymbol? {
-    return this.dispatchReceiverParameter?.symbol
-}
+internal fun IrFunction.getDispatchReceiver(): IrValueParameterSymbol? = this.dispatchReceiverParameter?.symbol
 
-fun IrFunction.getExtensionReceiver(): IrValueParameterSymbol? {
-    return this.extensionReceiverParameter?.symbol
-}
+internal fun IrFunction.getExtensionReceiver(): IrValueParameterSymbol? = this.extensionReceiverParameter?.symbol
 
-fun IrFunction.getReceiver(): IrSymbol? {
-    return this.getDispatchReceiver() ?: this.getExtensionReceiver()
-}
+internal fun IrFunction.getReceiver(): IrSymbol? = this.getDispatchReceiver() ?: this.getExtensionReceiver()
 
-fun IrFunctionAccessExpression.getBody(): IrBody? {
-    return this.symbol.owner.body
-}
+internal fun IrFunctionAccessExpression.getBody(): IrBody? = this.symbol.owner.body
 
-fun State.toIrExpression(expression: IrExpression): IrExpression {
+internal fun State.toIrExpression(expression: IrExpression): IrExpression {
     val start = expression.startOffset
     val end = expression.endOffset
     val type = expression.type.makeNotNull()
@@ -61,7 +53,7 @@ fun State.toIrExpression(expression: IrExpression): IrExpression {
     }
 }
 
-fun Any?.toState(irType: IrType): State {
+internal fun Any?.toState(irType: IrType): State {
     return when (this) {
         is State -> this
         is Boolean, is Char, is Byte, is Short, is Int, is Long, is String, is Float, is Double, is Array<*>, is ByteArray,
@@ -92,7 +84,7 @@ fun Any?.toIrConst(irType: IrType, startOffset: Int = UNDEFINED_OFFSET, endOffse
     }
 }
 
-fun <T> IrConst<T>.toPrimitive(): Primitive<T> {
+internal fun <T> IrConst<T>.toPrimitive(): Primitive<T> {
     return Primitive(this.value, this.type)
 }
 
@@ -109,13 +101,13 @@ fun IrAnnotationContainer.getAnnotation(annotation: FqName): IrConstructorCall {
         ?: ((this as IrFunction).parent as IrClass).annotations.first { it.symbol.owner.parentAsClass.fqNameWhenAvailable == annotation }
 }
 
-fun IrAnnotationContainer.getEvaluateIntrinsicValue(): String? {
+internal fun IrAnnotationContainer.getEvaluateIntrinsicValue(): String? {
     if (this is IrClass && this.fqNameWhenAvailable?.startsWith(Name.identifier("java")) == true) return this.fqNameWhenAvailable?.asString()
     if (!this.hasAnnotation(evaluateIntrinsicAnnotation)) return null
     return (this.getAnnotation(evaluateIntrinsicAnnotation).getValueArgument(0) as IrConst<*>).value.toString()
 }
 
-fun getPrimitiveClass(irType: IrType, asObject: Boolean = false): Class<*>? {
+internal fun getPrimitiveClass(irType: IrType, asObject: Boolean = false): Class<*>? {
     return when {
         irType.isBoolean() -> if (asObject) Boolean::class.javaObjectType else Boolean::class.java
         irType.isChar() -> if (asObject) Char::class.javaObjectType else Char::class.java
@@ -130,7 +122,7 @@ fun getPrimitiveClass(irType: IrType, asObject: Boolean = false): Class<*>? {
     }
 }
 
-fun IrFunction.getArgsForMethodInvocation(args: List<Variable>): List<Any?> {
+internal fun IrFunction.getArgsForMethodInvocation(args: List<Variable>): List<Any?> {
     val argsValues = args.map {
         when (val state = it.state) {
             is ExceptionState -> state.getThisAsCauseForException()
@@ -157,7 +149,7 @@ fun IrFunction.getLastOverridden(): IrFunction {
     return generateSequence(listOf(this)) { it.firstOrNull()?.overriddenSymbols?.map { it.owner } }.flatten().last()
 }
 
-fun List<Any?>.toPrimitiveStateArray(type: IrType): Primitive<*> {
+internal fun List<Any?>.toPrimitiveStateArray(type: IrType): Primitive<*> {
     return when {
         type.isByteArray() -> Primitive(ByteArray(size) { i -> (this[i] as Number).toByte() }, type)
         type.isCharArray() -> Primitive(CharArray(size) { i -> this[i] as Char }, type)
@@ -178,7 +170,7 @@ fun IrFunctionAccessExpression.getVarargType(index: Int): IrType? {
     return this.getTypeArgument(typeParameter.index)
 }
 
-fun getTypeArguments(
+internal fun getTypeArguments(
     container: IrTypeParametersContainer, expression: IrFunctionAccessExpression, mapper: (IrTypeParameterSymbol) -> State
 ): List<Variable> {
     fun IrType.getState(): State {
@@ -198,13 +190,13 @@ fun getTypeArguments(
     return typeArguments
 }
 
-fun State?.extractNonLocalDeclarations(): List<Variable> {
+internal fun State?.extractNonLocalDeclarations(): List<Variable> {
     this ?: return listOf()
     val state = this.takeIf { it !is Complex } ?: (this as Complex).getOriginal()
     return state.fields.filter { it.symbol !is IrFieldSymbol }
 }
 
-fun State?.getCorrectReceiverByFunction(irFunction: IrFunction): State? {
+internal fun State?.getCorrectReceiverByFunction(irFunction: IrFunction): State? {
     if (this !is Complex) return this
 
     val original: Complex? = this.getOriginal()
@@ -212,7 +204,7 @@ fun State?.getCorrectReceiverByFunction(irFunction: IrFunction): State? {
     return generateSequence(original) { it.superClass }.firstOrNull { it.irClass.thisReceiver == other } ?: this
 }
 
-fun State.checkNullability(irType: IrType?): State {
+internal fun State.checkNullability(irType: IrType?): State {
     if (irType !is IrSimpleType) return this
     if (this.isNull() && !irType.hasQuestionMark) {
         throw NullPointerException()
@@ -225,4 +217,4 @@ fun IrValueParameterSymbol.isNullable(): Boolean {
     return type.isNullable()
 }
 
-fun IrFunction.getCapitalizedFileName() = this.file.name.replace(".kt", "Kt").capitalize()
\ No newline at end of file
+internal fun IrFunction.getCapitalizedFileName() = this.file.name.replace(".kt", "Kt").capitalize()
\ No newline at end of file
diff --git a/compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/interpreter/intrinsics/IntrinsicEvaluator.kt b/compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/interpreter/intrinsics/IntrinsicEvaluator.kt
index 716f368e1e9..eed1260add5 100644
--- a/compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/interpreter/intrinsics/IntrinsicEvaluator.kt
+++ b/compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/interpreter/intrinsics/IntrinsicEvaluator.kt
@@ -11,7 +11,7 @@ import org.jetbrains.kotlin.backend.common.interpreter.stack.Stack
 import org.jetbrains.kotlin.ir.IrElement
 import org.jetbrains.kotlin.ir.declarations.IrFunction
 
-class IntrinsicEvaluator {
+internal class IntrinsicEvaluator {
     suspend fun evaluate(irFunction: IrFunction, stack: Stack, interpret: suspend IrElement.() -> ExecutionResult): ExecutionResult {
         return when {
             EmptyArray.equalTo(irFunction) -> EmptyArray.evaluate(irFunction, stack, interpret)
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 f35252e7731..e1bffd3a533 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
@@ -17,12 +17,12 @@ import org.jetbrains.kotlin.ir.declarations.IrFunction
 import org.jetbrains.kotlin.ir.types.classOrNull
 import org.jetbrains.kotlin.ir.util.*
 
-sealed class IntrinsicBase {
+internal sealed class IntrinsicBase {
     abstract fun equalTo(irFunction: IrFunction): Boolean
     abstract suspend fun evaluate(irFunction: IrFunction, stack: Stack, interpret: suspend IrElement.() -> ExecutionResult): ExecutionResult
 }
 
-object EmptyArray : IntrinsicBase() {
+internal object EmptyArray : IntrinsicBase() {
     override fun equalTo(irFunction: IrFunction): Boolean {
         val fqName = irFunction.fqNameWhenAvailable.toString()
         return fqName in setOf("kotlin.emptyArray", "kotlin.ArrayIntrinsicsKt.emptyArray")
@@ -37,7 +37,7 @@ object EmptyArray : IntrinsicBase() {
     }
 }
 
-object ArrayOf : IntrinsicBase() {
+internal object ArrayOf : IntrinsicBase() {
     override fun equalTo(irFunction: IrFunction): Boolean {
         val fqName = irFunction.fqNameWhenAvailable.toString()
         return fqName == "kotlin.arrayOf"
@@ -53,7 +53,7 @@ object ArrayOf : IntrinsicBase() {
     }
 }
 
-object ArrayOfNulls : IntrinsicBase() {
+internal object ArrayOfNulls : IntrinsicBase() {
     override fun equalTo(irFunction: IrFunction): Boolean {
         val fqName = irFunction.fqNameWhenAvailable.toString()
         return fqName == "kotlin.arrayOfNulls"
@@ -70,7 +70,7 @@ object ArrayOfNulls : IntrinsicBase() {
     }
 }
 
-object EnumValues : IntrinsicBase() {
+internal object EnumValues : IntrinsicBase() {
     override fun equalTo(irFunction: IrFunction): Boolean {
         val fqName = irFunction.fqNameWhenAvailable.toString()
         return (fqName == "kotlin.enumValues" || fqName.endsWith(".values")) && irFunction.valueParameters.isEmpty()
@@ -91,7 +91,7 @@ object EnumValues : IntrinsicBase() {
     }
 }
 
-object EnumValueOf : IntrinsicBase() {
+internal object EnumValueOf : IntrinsicBase() {
     override fun equalTo(irFunction: IrFunction): Boolean {
         val fqName = irFunction.fqNameWhenAvailable.toString()
         return (fqName == "kotlin.enumValueOf" || fqName.endsWith(".valueOf")) && irFunction.valueParameters.size == 1
@@ -113,7 +113,7 @@ object EnumValueOf : IntrinsicBase() {
     }
 }
 
-object RegexReplace : IntrinsicBase() {
+internal object RegexReplace : IntrinsicBase() {
     override fun equalTo(irFunction: IrFunction): Boolean {
         val fqName = irFunction.fqNameWhenAvailable.toString()
         return fqName == "kotlin.text.Regex.replace" && irFunction.valueParameters.size == 2
@@ -137,7 +137,7 @@ object RegexReplace : IntrinsicBase() {
     }
 }
 
-object EnumHashCode : IntrinsicBase() {
+internal object EnumHashCode : IntrinsicBase() {
     override fun equalTo(irFunction: IrFunction): Boolean {
         val fqName = irFunction.fqNameWhenAvailable.toString()
         return fqName == "kotlin.Enum.hashCode"
@@ -152,7 +152,7 @@ object EnumHashCode : IntrinsicBase() {
     }
 }
 
-object JsPrimitives : IntrinsicBase() {
+internal object JsPrimitives : IntrinsicBase() {
     override fun equalTo(irFunction: IrFunction): Boolean {
         val fqName = irFunction.fqNameWhenAvailable.toString()
         return fqName == "kotlin.Long.<init>" || fqName == "kotlin.Char.<init>"
@@ -176,7 +176,7 @@ object JsPrimitives : IntrinsicBase() {
     }
 }
 
-object ArrayConstructor : IntrinsicBase() {
+internal object ArrayConstructor : IntrinsicBase() {
     override fun equalTo(irFunction: IrFunction): Boolean {
         val fqName = irFunction.fqNameWhenAvailable.toString()
         return fqName.matches("kotlin\\.(Byte|Char|Short|Int|Long|Float|Double|Boolean|)Array\\.<init>".toRegex())
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 31ab87dd341..44218099b93 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
@@ -9,7 +9,7 @@ import org.jetbrains.kotlin.backend.common.interpreter.state.State
 import org.jetbrains.kotlin.ir.symbols.IrSymbol
 import org.jetbrains.kotlin.ir.symbols.IrTypeParameterSymbol
 
-interface Frame {
+internal interface Frame {
     fun addVar(variable: Variable)
     fun addAll(variables: List<Variable>)
     fun getVariable(symbol: IrSymbol): Variable?
@@ -23,7 +23,7 @@ interface Frame {
 }
 
 // TODO replace exceptions with InterpreterException
-class InterpreterFrame(
+internal class InterpreterFrame(
     private val pool: MutableList<Variable> = mutableListOf(),
     private val typeArguments: List<Variable> = listOf()
 ) : Frame {
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 2efd27e505e..c0f57fc3b0f 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
@@ -18,7 +18,7 @@ import org.jetbrains.kotlin.ir.util.fileEntry
 import org.jetbrains.kotlin.ir.util.fqNameWhenAvailable
 import org.jetbrains.kotlin.utils.addToStdlib.firstNotNullResult
 
-interface Stack {
+internal interface Stack {
     suspend fun newFrame(
         asSubFrame: Boolean = false, initPool: List<Variable> = listOf(), block: suspend () -> ExecutionResult
     ): ExecutionResult
@@ -39,7 +39,7 @@ interface Stack {
     fun peekReturnValue(): State
 }
 
-class StackImpl : Stack {
+internal class StackImpl : Stack {
     private val frameList = mutableListOf(FrameContainer()) // first frame is default, it is easier to work when last() is not null
     private fun getCurrentFrame() = frameList.last()
 
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 1840aafb005..94b4d754860 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
@@ -8,4 +8,5 @@ package org.jetbrains.kotlin.backend.common.interpreter.stack
 import org.jetbrains.kotlin.backend.common.interpreter.state.State
 import org.jetbrains.kotlin.ir.symbols.IrSymbol
 
-data class Variable(val symbol: IrSymbol, var state: State)
\ No newline at end of file
+// TODO maybe switch to typealias and use map instead of list
+internal data class Variable(val symbol: IrSymbol, var state: State)
\ No newline at end of file
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 16c575291cc..d208ea78966 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
@@ -13,7 +13,7 @@ import org.jetbrains.kotlin.ir.types.classOrNull
 import org.jetbrains.kotlin.ir.util.fqNameForIrSerialization
 import org.jetbrains.kotlin.ir.util.isInterface
 
-class Common private constructor(
+internal class Common private constructor(
     override val irClass: IrClass, override val fields: MutableList<Variable>
 ) : Complex(irClass, 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 08229dd7b34..fb4b9725976 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
@@ -18,7 +18,7 @@ import org.jetbrains.kotlin.ir.util.fqNameForIrSerialization
 import org.jetbrains.kotlin.ir.util.isInterface
 import org.jetbrains.kotlin.ir.util.overrides
 
-abstract class Complex(override val irClass: IrClass, override val fields: MutableList<Variable>) : State {
+internal 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
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 9d00a6e9e7d..489291f7f8b 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
@@ -15,7 +15,7 @@ import org.jetbrains.kotlin.ir.util.isSubclassOf
 import org.jetbrains.kotlin.ir.util.nameForIrSerialization
 import kotlin.math.min
 
-class ExceptionState private constructor(
+internal class ExceptionState private constructor(
     override val irClass: IrClass, override val fields: MutableList<Variable>, stackTrace: List<String>
 ) : Complex(irClass, fields) {
 
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 f36e9704d42..c8c97c0bb20 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
@@ -15,7 +15,7 @@ import org.jetbrains.kotlin.ir.util.nameForIrSerialization
 import org.jetbrains.kotlin.ir.util.render
 import org.jetbrains.kotlin.utils.addToStdlib.cast
 
-class Lambda(val irFunction: IrFunction, override val irClass: IrClass) : State {
+internal class Lambda(val irFunction: IrFunction, override val irClass: IrClass) : State {
     override val fields: MutableList<Variable> = mutableListOf()
     override val typeArguments: MutableList<Variable> = mutableListOf()
 
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 a149a269875..067c5267965 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
@@ -17,7 +17,7 @@ import org.jetbrains.kotlin.ir.types.IrType
 import org.jetbrains.kotlin.ir.types.classOrNull
 import org.jetbrains.kotlin.ir.util.isFakeOverride
 
-class Primitive<T>(var value: T, val type: IrType) : State {
+internal class Primitive<T>(var value: T, val type: IrType) : State {
     override val fields: MutableList<Variable> = mutableListOf()
     override val typeArguments: MutableList<Variable> = mutableListOf()
     override val irClass: IrClass = type.classOrNull!!.owner
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 9ed8e394c23..a60b5c8d251 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
@@ -13,7 +13,7 @@ import org.jetbrains.kotlin.ir.symbols.IrSymbol
 import org.jetbrains.kotlin.ir.types.*
 import org.jetbrains.kotlin.ir.util.defaultType
 
-interface State {
+internal interface State {
     val fields: MutableList<Variable>
     val irClass: IrClass
     val typeArguments: MutableList<Variable>
@@ -36,15 +36,15 @@ interface State {
     fun getIrFunctionByIrCall(expression: IrCall): IrFunction?
 }
 
-fun State.isNull() = this is Primitive<*> && this.value == null
+internal fun State.isNull() = this is Primitive<*> && this.value == null
 
-fun State.asInt() = (this as Primitive<*>).value as Int
-fun State.asBoolean() = (this as Primitive<*>).value as Boolean
-fun State.asString() = (this as Primitive<*>).value.toString()
+internal fun State.asInt() = (this as Primitive<*>).value as Int
+internal fun State.asBoolean() = (this as Primitive<*>).value as Boolean
+internal fun State.asString() = (this as Primitive<*>).value.toString()
 
-fun State.asBooleanOrNull() = (this as? Primitive<*>)?.value as? Boolean
+internal fun State.asBooleanOrNull() = (this as? Primitive<*>)?.value as? Boolean
 
-fun State.isSubtypeOf(other: IrType): Boolean {
+internal fun State.isSubtypeOf(other: IrType): Boolean {
     if (this is Primitive<*> && this.value == null) return other.isNullable()
 
     if (this is Primitive<*> && this.type.isArray() && other.isArray()) {
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 3806a66a14f..2651385ff2a 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
@@ -30,7 +30,7 @@ import java.lang.invoke.MethodHandle
 import java.lang.invoke.MethodHandles
 import java.lang.invoke.MethodType
 
-class Wrapper(val value: Any, override val irClass: IrClass) : Complex(irClass, mutableListOf()) {
+internal class Wrapper(val value: Any, override val irClass: IrClass) : Complex(irClass, mutableListOf()) {
 
     private val typeFqName = irClass.fqNameForIrSerialization.toUnsafe()
     private val receiverClass = irClass.defaultType.getClass(true)