kotlinx.atomicfu compiler plugin (JS): delegated properties supported (#4692)

* kotlinx.atomicfu compiler plugin (JS): delegated properties supported

* NPE handling fixed

* Scoped delegated properties supported

plugins/atomicfu/atomicfu-compiler/src/org.jetbrains.kotlinx.atomicfu.compiler/extensions/AtomicfuTransformer.kt

@@ -29,6 +29,8 @@ private const val TRACE_BASE_TYPE = "TraceBase"
 private const val GETTER = "atomicfu\$getter"
 private const val SETTER = "atomicfu\$setter"
 private const val GET = "get"
+private const val GET_VALUE = "getValue"
+private const val SET_VALUE = "setValue"
 private const val ATOMIC_VALUE_FACTORY = "atomic"
 private const val TRACE = "Trace"
 private const val INVOKE = "invoke"
@@ -101,6 +103,39 @@ class AtomicfuTransformer(private val context: IrPluginContext) {
 
     private inner class AtomicTransformer : IrElementTransformer<IrFunction?> {
 
+        override fun visitProperty(declaration: IrProperty, data: IrFunction?): IrStatement {
+            // Support transformation for delegated properties:
+            if (declaration.isDelegated && declaration.backingField?.type?.isAtomicValueType() == true) {
+                declaration.backingField?.let { delegateBackingField ->
+                    delegateBackingField.initializer?.let {
+                        val initializer = it.expression as IrCall
+                        when {
+                            initializer.isAtomicFieldGetter() -> {
+                                // val _a = atomic(0)
+                                // var a: Int by _a
+                                // Accessors of the delegated property `a` are implemented via the generated property `a$delegate`,
+                                // that is the copy of the original `_a`.
+                                // They should be delegated to the value of the original field `_a` instead of `a$delegate`.
+
+                                // fun <get-a>() = a$delegate.value -> _a.value
+                                // fun <set-a>(value: Int) = { a$delegate.value = value } -> { _a.value = value }
+                                val originalField = initializer.getBackingField()
+                                declaration.transform(DelegatePropertyTransformer(originalField, initializer.dispatchReceiver, false), null)
+                            }
+                            initializer.isAtomicFactory() -> {
+                                // var a by atomic(77) -> var a: Int = 77
+                                it.expression = initializer.eraseAtomicFactory()
+                                    ?: error("Atomic factory was expected but found ${initializer.render()}")
+                                declaration.transform(DelegatePropertyTransformer(delegateBackingField, initializer.dispatchReceiver, true), null)
+                            }
+                            else -> error("Unexpected initializer of the delegated property: $initializer")
+                        }
+                    }
+                }
+            }
+            return super.visitProperty(declaration, data)
+        }
+
         override fun visitFunction(declaration: IrFunction, data: IrFunction?): IrStatement {
             return super.visitFunction(declaration, declaration)
         }
@@ -233,6 +268,46 @@ class AtomicfuTransformer(private val context: IrPluginContext) {
             return super.visitConstructorCall(expression, data)
         }
 
+        private inner class DelegatePropertyTransformer(
+            val originalField: IrField,
+            val receiver: IrExpression?,
+            val isInitializedWithAtomicFactory: Boolean
+        ): IrElementTransformerVoid() {
+            override fun visitCall(expression: IrCall): IrExpression {
+                // Accessors of the delegated property have following signatures:
+
+                // public inline operator fun setValue(thisRef: Any?, property: KProperty<*>, value: T)
+                // public inline operator fun getValue(thisRef: Any?, property: KProperty<*>): T
+
+                // getValue/setValue should get and set the value of the originalField
+                val name = expression.symbol.owner.name.asString()
+                if (expression.symbol.isKotlinxAtomicfuPackage() && (name == GET_VALUE || name == SET_VALUE)) {
+                    val type = originalField.type.atomicToValueType()
+                    val isSetter = name == SET_VALUE
+                    val runtimeFunction = getRuntimeFunctionSymbol(name, type)
+                    val dispatchReceiver = if (isInitializedWithAtomicFactory) {
+                        val thisRef = expression.getValueArgument(0)!!
+                        if (thisRef.isConstNull()) null else thisRef
+                    } else {
+                        receiver
+                    }
+                    val fieldAccessors = listOf(
+                        context.buildFieldAccessor(originalField, dispatchReceiver, false),
+                        context.buildFieldAccessor(originalField, dispatchReceiver, true)
+                    )
+                    return buildCall(
+                        UNDEFINED_OFFSET, UNDEFINED_OFFSET,
+                        target = runtimeFunction,
+                        type = type,
+                        typeArguments = if (runtimeFunction.owner.typeParameters.size == 1) listOf(type) else emptyList(),
+                        valueArguments = if (isSetter) listOf(expression.getValueArgument(2)!!, fieldAccessors[0], fieldAccessors[1]) else
+                                fieldAccessors
+                    )
+                }
+                return super.visitCall(expression)
+            }
+        }
+
         private fun IrExpression.getReceiverAccessors(parent: IrFunction?): List<IrExpression>? =
             when {
                 this is IrCall -> getAccessors()
@@ -297,27 +372,36 @@ class AtomicfuTransformer(private val context: IrPluginContext) {
                 it.type.isAtomicArrayType() && symbol.owner.name.asString() == GET
             } ?: false
 
+        private fun IrCall.getAccessors(): List<IrExpression> =
+            if (!isArrayElementGetter()) {
+                val field = getBackingField()
+                listOf(
+                    context.buildFieldAccessor(field, dispatchReceiver, false),
+                    context.buildFieldAccessor(field, dispatchReceiver, true)
+                )
+            } else {
+                val index = getValueArgument(0)!!
+                val arrayGetter = dispatchReceiver as IrCall
+                val arrayField = arrayGetter.getBackingField()
+                listOf(
+                    context.buildArrayElementAccessor(arrayField, arrayGetter, index, false),
+                    context.buildArrayElementAccessor(arrayField, arrayGetter, index, true)
+                )
+            }
+
         private fun IrStatement.isTrace() =
             this is IrCall && (isTraceInvoke() || isTraceAppend())
 
         private fun IrCall.isTraceInvoke(): Boolean =
             symbol.isKotlinxAtomicfuPackage() &&
-            symbol.owner.name.asString() == INVOKE &&
-            symbol.owner.dispatchReceiverParameter?.type?.isTraceBaseType() == true
+                    symbol.owner.name.asString() == INVOKE &&
+                    symbol.owner.dispatchReceiverParameter?.type?.isTraceBaseType() == true
 
         private fun IrCall.isTraceAppend(): Boolean =
             symbol.isKotlinxAtomicfuPackage() &&
-            symbol.owner.name.asString() == APPEND &&
-            symbol.owner.dispatchReceiverParameter?.type?.isTraceBaseType() == true
+                    symbol.owner.name.asString() == APPEND &&
+                    symbol.owner.dispatchReceiverParameter?.type?.isTraceBaseType() == true
 
-        private fun IrCall.getAccessors(): List<IrExpression> {
-            val isArrayElement = isArrayElementGetter()
-            val valueType = type.atomicToValueType()
-            return listOf(
-                context.buildAccessorLambda(this, valueType, false, isArrayElement),
-                context.buildAccessorLambda(this, valueType, true, isArrayElement)
-            )
-        }
 
         private fun getRuntimeFunctionSymbol(name: String, type: IrType): IrSimpleFunctionSymbol {
             val functionName = when (name) {
@@ -340,11 +424,11 @@ class AtomicfuTransformer(private val context: IrPluginContext) {
 
         private fun IrCall.getAtomicFunctionName(): String =
             symbol.signature?.let { signature ->
-                if (signature is IdSignature.AccessorSignature) signature.accessorSignature else signature.asPublic()
-            }?.declarationFqName?.let { name ->
-                if (name.substringBefore('.') in ATOMIC_VALUE_TYPES) {
-                    name.substringAfter('.')
-                } else name
+                signature.getDeclarationNameBySignature()?.let { name ->
+                    if (name.substringBefore('.') in ATOMIC_VALUE_TYPES) {
+                        name.substringAfter('.')
+                    } else name
+                }
             } ?: error("Incorrect pattern of the atomic function name: ${symbol.owner.render()}")
 
         private fun IrCall.eraseAtomicFactory() =
@@ -415,6 +499,9 @@ class AtomicfuTransformer(private val context: IrPluginContext) {
         symbol.isKotlinxAtomicfuPackage() && symbol.owner.name.asString() == ATOMIC_ARRAY_OF_NULLS_FACTORY &&
                 type.isAtomicArrayType()
 
+    private fun IrCall.isAtomicFieldGetter(): Boolean =
+        type.isAtomicValueType() && symbol.owner.name.asString().startsWith("<get-")
+
     private fun IrConstructorCall.isAtomicArrayConstructor(): Boolean = type.isAtomicArrayType()
 
     private fun IrCall.isReentrantLockFactory(): Boolean =

plugins/atomicfu/atomicfu-compiler/src/org.jetbrains.kotlinx.atomicfu.compiler/extensions/TransformerUtil.kt

@@ -5,12 +5,11 @@
 
 package org.jetbrains.kotlinx.atomicfu.compiler.extensions
 
-import org.jetbrains.kotlin.backend.common.deepCopyWithVariables
 import org.jetbrains.kotlin.backend.common.extensions.IrPluginContext
 import org.jetbrains.kotlin.descriptors.DescriptorVisibilities
 import org.jetbrains.kotlin.ir.IrStatement
 import org.jetbrains.kotlin.ir.UNDEFINED_OFFSET
-import org.jetbrains.kotlin.ir.backend.js.ir.JsIrBuilder
+import org.jetbrains.kotlin.ir.backend.js.ir.JsIrBuilder.buildValueParameter
 import org.jetbrains.kotlin.ir.builders.declarations.buildFun
 import org.jetbrains.kotlin.ir.declarations.*
 import org.jetbrains.kotlin.ir.expressions.*
@@ -18,6 +17,8 @@ import org.jetbrains.kotlin.ir.expressions.impl.*
 import org.jetbrains.kotlin.ir.symbols.*
 import org.jetbrains.kotlin.ir.types.*
 import org.jetbrains.kotlin.ir.types.impl.*
+import org.jetbrains.kotlin.ir.util.IdSignature
+import org.jetbrains.kotlin.ir.util.render
 import org.jetbrains.kotlin.name.FqName
 import org.jetbrains.kotlin.name.Name
 import org.jetbrains.kotlin.types.Variance
@@ -120,11 +121,13 @@ internal fun buildGetValue(
 
 internal fun IrPluginContext.buildConstNull() = IrConstImpl.constNull(UNDEFINED_OFFSET, UNDEFINED_OFFSET, irBuiltIns.anyNType)
 
-internal fun getterName(getterCall: IrCall) = "<get-${getterCall.symbol.owner.name.getFieldName()}>"
-internal fun setterName(getterCall: IrCall) = "<set-${getterCall.symbol.owner.name.getFieldName()}>"
+internal fun IrExpression.isConstNull() = this is IrConst<*> && this.kind.asString == "Null"
 
-private fun Name.getFieldName() = "<get-(\\w+)>".toRegex().find(asString())?.groupValues?.get(1)
-    ?: error("Getter name ${this.asString()} does not match special name pattern <get-fieldName>")
+internal fun IrField.getterName() = "<get-${name.asString()}>"
+internal fun IrField.setterName() = "<set-${name.asString()}>"
+
+internal fun String.getFieldName() = "<get-(\\w+)>".toRegex().find(this)?.groupValues?.get(1)
+    ?: error("Getter name $this does not match special name pattern <get-fieldName>")
 
 internal fun IrFunctionAccessExpression.getValueArguments() =
     (0 until valueArgumentsCount).map { i ->
@@ -162,82 +165,108 @@ private fun buildGetField(backingField: IrField, ownerClass: IrExpression?): IrG
     )
 }
 
-internal fun IrPluginContext.buildAccessorLambda(
-    getter: IrCall,
-    valueType: IrType,
-    isSetter: Boolean,
-    isArrayElement: Boolean
-): IrExpression {
-    val getterCall = if (isArrayElement) getter.dispatchReceiver as IrCall else getter
-    val type = if (isSetter) buildSetterType(valueType) else buildGetterType(valueType)
-    val name = if (isSetter) setterName(getterCall) else getterName(getterCall)
-    val returnType = if (isSetter) irBuiltIns.unitType else valueType
-    val accessorFunction = irFactory.buildFun {
+private fun IrPluginContext.buildDefaultPropertyAccessor(name: String): IrSimpleFunction =
+    irFactory.buildFun {
         startOffset = UNDEFINED_OFFSET
         endOffset = UNDEFINED_OFFSET
         this.origin = IrDeclarationOrigin.DEFAULT_PROPERTY_ACCESSOR
-        this.name = Name.identifier(name)
         this.visibility = DescriptorVisibilities.LOCAL
         this.isInline = true
-        this.returnType = returnType
-    }.apply {
-        val valueParameter = JsIrBuilder.buildValueParameter(this, name, 0, valueType)
+        this.name = Name.identifier(name)
+    }
+
+internal fun IrPluginContext.buildArrayElementAccessor(
+    arrayField: IrField,
+    arrayGetter: IrCall,
+    index: IrExpression,
+    isSetter: Boolean
+): IrExpression {
+    val valueType = arrayField.type
+    val functionType = if (isSetter) buildSetterType(valueType) else buildGetterType(valueType)
+    val returnType = if (isSetter) irBuiltIns.unitType else valueType
+    val name = if (isSetter) arrayField.setterName() else arrayField.getterName()
+    val accessorFunction = buildDefaultPropertyAccessor(name).apply {
+        val valueParameter = buildValueParameter(this, name, 0, valueType)
         this.valueParameters = if (isSetter) listOf(valueParameter) else emptyList()
-        val body = if (isSetter) {
-            if (isArrayElement) {
-                val setSymbol = referenceFunction(referenceArrayClass(getterCall.type as IrSimpleType), SET)
-                val elementIndex = getter.getValueArgument(0)!!.deepCopyWithVariables()
-                buildCall(
-                    UNDEFINED_OFFSET, UNDEFINED_OFFSET,
-                    target = setSymbol,
-                    type = irBuiltIns.unitType,
-                    origin = IrStatementOrigin.LAMBDA,
-                    valueArguments = listOf(elementIndex, valueParameter.capture())
-                ).apply {
-                    dispatchReceiver = getterCall
+        body = irFactory.buildBlockBody(
+            listOf(
+                if (isSetter) {
+                    val setSymbol = referenceFunction(referenceArrayClass(arrayField.type as IrSimpleType), SET)
+                    buildCall(
+                        UNDEFINED_OFFSET, UNDEFINED_OFFSET,
+                        target = setSymbol,
+                        type = irBuiltIns.unitType,
+                        origin = IrStatementOrigin.LAMBDA,
+                        valueArguments = listOf(index, valueParameter.capture())
+                    ).apply {
+                        this.dispatchReceiver = arrayGetter
+                    }
+                } else {
+                    val getField = buildGetField(arrayField, arrayGetter.dispatchReceiver)
+                    val getSymbol = referenceFunction(referenceArrayClass(arrayField.type as IrSimpleType), GET)
+                    buildCall(
+                        UNDEFINED_OFFSET, UNDEFINED_OFFSET,
+                        target = getSymbol,
+                        type = valueType,
+                        origin = IrStatementOrigin.LAMBDA,
+                        valueArguments = listOf(index)
+                    ).apply {
+                        dispatchReceiver = getField
+                    }
                 }
-            } else {
-                buildSetField(getterCall.getBackingField(), getterCall.dispatchReceiver, valueParameter.capture())
-            }
-        } else {
-            val getField = buildGetField(getterCall.getBackingField(), getterCall.dispatchReceiver)
-            if (isArrayElement) {
-                val getSymbol = referenceFunction(referenceArrayClass(getterCall.type as IrSimpleType), GET)
-                val elementIndex = getter.getValueArgument(0)!!.deepCopyWithVariables()
-                buildCall(
-                    UNDEFINED_OFFSET, UNDEFINED_OFFSET,
-                    target = getSymbol,
-                    type = valueType,
-                    origin = IrStatementOrigin.LAMBDA,
-                    valueArguments = listOf(elementIndex)
-                ).apply {
-                    dispatchReceiver = getField.deepCopyWithVariables()
-                }
-            } else {
-                getField.deepCopyWithVariables()
-            }
-        }
-        this.body = irFactory.buildBlockBody(listOf(body))
-        origin = IrDeclarationOrigin.DEFAULT_PROPERTY_ACCESSOR
+            )
+        )
+        this.returnType = returnType
     }
     return IrFunctionExpressionImpl(
         UNDEFINED_OFFSET, UNDEFINED_OFFSET,
-        type,
+        functionType,
         accessorFunction,
         IrStatementOrigin.LAMBDA
     )
 }
 
-private fun IrCall.getBackingField(): IrField {
-    val correspondingPropertySymbol = symbol.owner.correspondingPropertySymbol!!
-    return correspondingPropertySymbol.owner.backingField!!
+internal fun IrPluginContext.buildFieldAccessor(
+    field: IrField,
+    dispatchReceiver: IrExpression?,
+    isSetter: Boolean
+): IrExpression {
+    val valueType = field.type
+    val functionType = if (isSetter) buildSetterType(valueType) else buildGetterType(valueType)
+    val returnType = if (isSetter) irBuiltIns.unitType else valueType
+    val name = if (isSetter) field.setterName() else field.getterName()
+    val accessorFunction = buildDefaultPropertyAccessor(name).apply {
+        val valueParameter = buildValueParameter(this, name, 0, valueType)
+        valueParameters = if (isSetter) listOf(valueParameter) else emptyList()
+        body = irFactory.buildBlockBody(
+            listOf(
+                if (isSetter) {
+                    buildSetField(field, dispatchReceiver, valueParameter.capture())
+                } else {
+                    buildGetField(field, dispatchReceiver)
+                }
+            )
+        )
+        this.returnType = returnType
+    }
+    return IrFunctionExpressionImpl(
+        UNDEFINED_OFFSET, UNDEFINED_OFFSET,
+        functionType,
+        accessorFunction,
+        IrStatementOrigin.LAMBDA
+    )
 }
 
+internal fun IrCall.getBackingField(): IrField =
+    symbol.owner.correspondingPropertySymbol?.let { propertySymbol ->
+        propertySymbol.owner.backingField ?: error("Property expected to have backing field")
+    } ?: error("Atomic property accessor ${this.render()} expected to have non-null correspondingPropertySymbol")
+
 internal fun IrPluginContext.referencePackageFunction(
     packageName: String,
     name: String,
     predicate: (IrFunctionSymbol) -> Boolean = { true }
-) = try {
+): IrSimpleFunctionSymbol = try {
         referenceFunctions(FqName("$packageName.$name")).single(predicate)
     } catch (e: RuntimeException) {
         error("Exception while looking for the function `$name` in package `$packageName`: ${e.message}")
@@ -253,13 +282,32 @@ internal fun IrPluginContext.referenceFunction(classSymbol: IrClassSymbol, funct
 }
 
 private fun IrPluginContext.referenceArrayClass(irType: IrSimpleType): IrClassSymbol {
-    val afuClassId = (irType.classifier.signature!!.asPublic())!!.declarationFqName
-    val classId = FqName("$KOTLIN.${AFU_ARRAY_CLASSES[afuClassId]!!}")
-    return referenceClass(classId)!!
+    val jsArrayName = irType.getArrayClassFqName()
+    return referenceClass(jsArrayName) ?: error("Array class $jsArrayName was not found in the context")
 }
 
-internal fun IrPluginContext.getArrayConstructorSymbol(irType: IrSimpleType, predicate: (IrConstructorSymbol) -> Boolean = { true }): IrConstructorSymbol {
-    val afuClassId = (irType.classifier.signature!!.asPublic())!!.declarationFqName
-    val classId = FqName("$KOTLIN.${AFU_ARRAY_CLASSES[afuClassId]!!}")
-    return referenceConstructors(classId).single(predicate)
+internal fun IrPluginContext.getArrayConstructorSymbol(
+    irType: IrSimpleType,
+    predicate: (IrConstructorSymbol) -> Boolean = { true }
+): IrConstructorSymbol {
+    val jsArrayName = irType.getArrayClassFqName()
+    return try {
+        referenceConstructors(jsArrayName).single(predicate)
+    } catch (e: RuntimeException) {
+        error("Array constructor $jsArrayName matching the predicate was not found in the context")
+    }
 }
+
+private fun IrSimpleType.getArrayClassFqName(): FqName =
+    classifier.signature?.let { signature ->
+        signature.getDeclarationNameBySignature().let { name ->
+            AFU_ARRAY_CLASSES[name]?.let { jsArrayName ->
+                FqName("$KOTLIN.$jsArrayName")
+            }
+        }
+    } ?: error("Unexpected array type ${this.render()}")
+
+internal fun IdSignature.getDeclarationNameBySignature(): String? {
+    val commonSignature = if (this is IdSignature.AccessorSignature) accessorSignature else asPublic()
+    return commonSignature?.declarationFqName
+}

plugins/atomicfu/atomicfu-compiler/test/org/jetbrains/kotlinx/atomicfu/AtomicfuJsIrTestGenerated.java

@@ -43,6 +43,12 @@ public class AtomicfuJsIrTestGenerated extends AbstractAtomicfuJsIrTest {
         runTest("plugins/atomicfu/atomicfu-compiler/testData/box/AtomicArrayTest.kt");
     }
 
+    @Test
+    @TestMetadata("DelegatedPropertiesTest.kt")
+    public void testDelegatedPropertiesTest() throws Exception {
+        runTest("plugins/atomicfu/atomicfu-compiler/testData/box/DelegatedPropertiesTest.kt");
+    }
+
     @Test
     @TestMetadata("ExtensionsTest.kt")
     public void testExtensionsTest() throws Exception {

plugins/atomicfu/atomicfu-compiler/testData/box/DelegatedPropertiesTest.kt

@@ -0,0 +1,144 @@
+import kotlinx.atomicfu.*
+import kotlin.test.*
+
+private val _topLevelInt = atomic(42)
+var topLevelInt: Int by _topLevelInt
+
+var vIntTopLevel by atomic(55)
+
+class DelegatedProperties {
+    private val _a = atomic(42)
+    var a: Int by _a
+
+    private val _l = atomic(55555555555)
+    var l: Long by _l
+
+    private val _b = atomic(false)
+    var b: Boolean by _b
+
+    private val _ref = atomic(A(B(77)))
+    var ref: A by _ref
+
+    var vInt by atomic(77)
+
+    var vLong by atomic(777777777)
+
+    var vBoolean by atomic(false)
+
+    var vRef by atomic(A(B(77)))
+
+    class A (val b: B)
+    class B (val n: Int)
+
+    fun testDelegatedAtomicInt() {
+        assertEquals(42, a)
+        _a.compareAndSet(42, 56)
+        assertEquals(56, a)
+        a = 77
+        _a.compareAndSet(77,  66)
+        assertEquals(66, _a.value)
+        assertEquals(66, a)
+    }
+
+    fun testDelegatedAtomicLong() {
+        assertEquals(55555555555, l)
+        _l.getAndIncrement()
+        assertEquals(55555555556, l)
+        l = 7777777777777
+        assertTrue(_l.compareAndSet(7777777777777, 66666666666))
+        assertEquals(66666666666, _l.value)
+        assertEquals(66666666666, l)
+    }
+
+    fun testDelegatedAtomicBoolean() {
+        assertEquals(false, b)
+        _b.lazySet(true)
+        assertEquals(true, b)
+        b = false
+        assertTrue(_b.compareAndSet(false, true))
+        assertEquals(true, _b.value)
+        assertEquals(true, b)
+    }
+
+    fun testDelegatedAtomicRef() {
+        assertEquals(77, ref.b.n)
+        _ref.lazySet(A(B(66)))
+        assertEquals(66, ref.b.n)
+        assertTrue(_ref.compareAndSet(_ref.value, A(B(56))))
+        assertEquals(56, ref.b.n)
+        ref = A(B(99))
+        assertEquals(99, _ref.value.b.n)
+    }
+
+    fun testVolatileInt() {
+        assertEquals(77, vInt)
+        vInt = 55
+        assertEquals(110, vInt * 2)
+    }
+
+    fun testVolatileLong() {
+        assertEquals(777777777, vLong)
+        vLong = 55
+        assertEquals(55, vLong)
+    }
+
+    fun testVolatileBoolean() {
+        assertEquals(false, vBoolean)
+        vBoolean = true
+        assertEquals(true, vBoolean)
+    }
+
+    fun testVolatileRef() {
+        assertEquals(77, vRef.b.n)
+        vRef = A(B(99))
+        assertEquals(99, vRef.b.n)
+    }
+
+    inner class D {
+        var b: Int by _a
+    }
+
+    fun testScopedDelegatedProperties() {
+        val clazz = D()
+        clazz.b = 42
+        _a.compareAndSet(42, 56)
+        assertEquals(56, clazz.b)
+        clazz.b = 77
+        _a.compareAndSet(77, 66)
+        assertEquals(66, _a.value)
+        assertEquals(66, clazz.b)
+    }
+
+    fun test() {
+        testDelegatedAtomicInt()
+        testDelegatedAtomicLong()
+        testDelegatedAtomicBoolean()
+        testDelegatedAtomicRef()
+        testVolatileInt()
+        testVolatileBoolean()
+        testVolatileLong()
+        testVolatileRef()
+        testScopedDelegatedProperties()
+    }
+}
+
+fun testTopLevelDelegatedProperties() {
+    assertEquals(42, topLevelInt)
+    _topLevelInt.compareAndSet(42, 56)
+    assertEquals(56, topLevelInt)
+    topLevelInt = 77
+    _topLevelInt.compareAndSet(77, 66)
+    assertEquals(66, _topLevelInt.value)
+    assertEquals(66, topLevelInt)
+
+    assertEquals(55, vIntTopLevel)
+    vIntTopLevel = 70
+    assertEquals(140, vIntTopLevel * 2)
+}
+
+fun box(): String {
+    val testClass = DelegatedProperties()
+    testClass.test()
+    //testTopLevelDelegatedProperties()
+    return "OK"
+}