IR: explicitly pass isFakeOverride to buildFun and friends

compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/ir/IrUtils.kt

@@ -560,6 +560,7 @@ fun createStaticFunctionWithReceivers(
     origin: IrDeclarationOrigin = oldFunction.origin,
     modality: Modality = Modality.FINAL,
     visibility: Visibility = oldFunction.visibility,
+    isFakeOverride: Boolean = oldFunction.isFakeOverride,
     copyMetadata: Boolean = true,
     typeParametersFromContext: List<IrTypeParameter> = listOf()
 ): IrSimpleFunction {
@@ -579,7 +580,7 @@ fun createStaticFunctionWithReceivers(
         isTailrec = false,
         isSuspend = oldFunction.isSuspend,
         isExpect = oldFunction.isExpect,
-        isFakeOverride = origin == IrDeclarationOrigin.FAKE_OVERRIDE,
+        isFakeOverride = isFakeOverride,
         isOperator = oldFunction is IrSimpleFunction && oldFunction.isOperator
     ).apply {
         descriptor.bind(this)

compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/lower/DefaultArgumentStubGenerator.kt

@@ -425,7 +425,7 @@ private fun IrFunction.generateDefaultsFunction(
     if (this is IrSimpleFunction) {
         // If this is an override of a function with default arguments, produce a fake override of a default stub.
         if (overriddenSymbols.any { it.owner.findBaseFunctionWithDefaultArguments(skipInlineMethods, skipExternalMethods) != null })
-            return generateDefaultsFunctionImpl(context, IrDeclarationOrigin.FAKE_OVERRIDE, visibility).also {
+            return generateDefaultsFunctionImpl(context, IrDeclarationOrigin.FAKE_OVERRIDE, visibility, isFakeOverride = true).also {
                 context.mapping.defaultArgumentsDispatchFunction[this] = it
                 context.mapping.defaultArgumentsOriginalFunction[it] = this
 
@@ -453,7 +453,9 @@ private fun IrFunction.generateDefaultsFunction(
     // Since this bug causes the metadata serializer to write the "has default value" flag into compiled
     // binaries, it's way too late to fix it. Hence the workaround.
     if (valueParameters.any { it.defaultValue != null }) {
-        return generateDefaultsFunctionImpl(context, IrDeclarationOrigin.FUNCTION_FOR_DEFAULT_PARAMETER, visibility).also {
+        return generateDefaultsFunctionImpl(
+            context, IrDeclarationOrigin.FUNCTION_FOR_DEFAULT_PARAMETER, visibility, isFakeOverride = false
+        ).also {
             context.mapping.defaultArgumentsDispatchFunction[this] = it
             context.mapping.defaultArgumentsOriginalFunction[it] = this
         }
@@ -464,7 +466,8 @@ private fun IrFunction.generateDefaultsFunction(
 private fun IrFunction.generateDefaultsFunctionImpl(
     context: CommonBackendContext,
     newOrigin: IrDeclarationOrigin,
-    newVisibility: Visibility
+    newVisibility: Visibility,
+    isFakeOverride: Boolean
 ): IrFunction {
     val newFunction = when (this) {
         is IrConstructor ->
@@ -481,6 +484,7 @@ private fun IrFunction.generateDefaultsFunctionImpl(
                 updateFrom(this@generateDefaultsFunctionImpl)
                 name = Name.identifier("${this@generateDefaultsFunctionImpl.name}\$default")
                 origin = newOrigin
+                this.isFakeOverride = isFakeOverride
                 modality = Modality.FINAL
                 isExternal = false
                 isTailrec = false

compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/lower/LateinitLowering.kt

@@ -213,4 +213,4 @@ private fun CommonBackendContext.buildOrGetNullableField(originalField: IrField)
     }
 }
 
-private val IrProperty.isRealLateinit get() = isLateinit && getter?.isFakeOverride != true
+private val IrProperty.isRealLateinit get() = isLateinit && !isFakeOverride

compiler/ir/backend.common/src/org/jetbrains/kotlin/ir/builders/declarations/declarationBuilders.kt

@@ -44,8 +44,7 @@ fun IrFieldBuilder.buildField(): IrField {
     return IrFieldImpl(
         startOffset, endOffset, origin,
         IrFieldSymbolImpl(wrappedDescriptor),
-        name, type, visibility, isFinal, isExternal, isStatic,
-        origin == IrDeclarationOrigin.FAKE_OVERRIDE
+        name, type, visibility, isFinal, isExternal, isStatic, isFakeOverride
     ).also {
         it.metadata = metadata
         wrappedDescriptor.bind(it)
@@ -81,7 +80,7 @@ fun IrPropertyBuilder.buildProperty(): IrProperty {
         IrPropertySymbolImpl(wrappedDescriptor),
         name, visibility, modality,
         isVar = isVar, isConst = isConst, isLateinit = isLateinit, isDelegated = isDelegated, isExpect = isExpect, isExternal = isExternal,
-        isFakeOverride = origin == IrDeclarationOrigin.FAKE_OVERRIDE
+        isFakeOverride = isFakeOverride
     ).also {
         wrappedDescriptor.bind(it)
     }
@@ -133,8 +132,7 @@ fun IrFunctionBuilder.buildFun(originalDescriptor: FunctionDescriptor? = null):
         IrSimpleFunctionSymbolImpl(wrappedDescriptor),
         name, visibility, modality, returnType,
         isInline = isInline, isExternal = isExternal, isTailrec = isTailrec, isSuspend = isSuspend, isExpect = isExpect,
-        isFakeOverride = origin == IrDeclarationOrigin.FAKE_OVERRIDE,
-        isOperator = isOperator
+        isFakeOverride = isFakeOverride, isOperator = isOperator
     ).also {
         wrappedDescriptor.bind(it)
     }
@@ -183,6 +181,7 @@ fun IrDeclarationContainer.addFunction(
     visibility: Visibility = Visibilities.PUBLIC,
     isStatic: Boolean = false,
     isSuspend: Boolean = false,
+    isFakeOverride: Boolean = false,
     origin: IrDeclarationOrigin = IrDeclarationOrigin.DEFINED
 ): IrSimpleFunction =
     addFunction {
@@ -191,6 +190,7 @@ fun IrDeclarationContainer.addFunction(
         this.modality = modality
         this.visibility = visibility
         this.isSuspend = isSuspend
+        this.isFakeOverride = isFakeOverride
         this.origin = origin
     }.apply {
         if (!isStatic) {

compiler/ir/backend.jvm/src/org/jetbrains/kotlin/backend/jvm/descriptors/JvmDeclarationFactory.kt

@@ -180,8 +180,8 @@ class JvmDeclarationFactory(
     fun getStaticBackingField(irProperty: IrProperty): IrField? {
         // Only fields defined directly in objects should be made static.
         // Fake overrides never point to those, as objects are final.
+        if (irProperty.isFakeOverride) return null
         val oldField = irProperty.backingField ?: return null
-        if (oldField.isFakeOverride) return null
         val oldParent = irProperty.parent as? IrClass ?: return null
         if (!oldParent.isObject) return null
         return staticBackingFields.getOrPut(irProperty) {
@@ -238,6 +238,7 @@ class JvmDeclarationFactory(
                 // We should rather not generate a bridge to clone when interface inherits from Cloneable at all.
                 visibility = if (interfaceFun.visibility == Visibilities.PRIVATE) Visibilities.PRIVATE else Visibilities.PUBLIC,
 
+                isFakeOverride = false,
                 typeParametersFromContext = parent.typeParameters
             )
         }
@@ -270,7 +271,6 @@ class JvmDeclarationFactory(
 
     fun getDefaultImplsRedirection(fakeOverride: IrSimpleFunction): IrSimpleFunction =
         defaultImplsRedirections.getOrPut(fakeOverride) {
-            assert(fakeOverride.origin == IrDeclarationOrigin.FAKE_OVERRIDE)
             assert(fakeOverride.isFakeOverride)
             val irClass = fakeOverride.parentAsClass
             val descriptor = DescriptorsToIrRemapper.remapDeclaredSimpleFunction(fakeOverride.descriptor)

compiler/ir/backend.jvm/src/org/jetbrains/kotlin/backend/jvm/lower/AddContinuationLowering.kt

@@ -527,6 +527,7 @@ private class AddContinuationLowering(private val context: JvmBackendContext) :
             irFunction.name.toSuspendImplementationName(),
             irFunction,
             origin = JvmLoweredDeclarationOrigin.SUSPEND_IMPL_STATIC_FUNCTION,
+            isFakeOverride = false,
             copyMetadata = false
         )
         static.body = irFunction.moveBodyTo(static)

compiler/ir/backend.jvm/src/org/jetbrains/kotlin/backend/jvm/lower/BridgeLowering.kt

@@ -333,6 +333,7 @@ private class BridgeLowering(val context: JvmBackendContext) : FileLoweringPass,
             origin = IrDeclarationOrigin.DEFINED
             name = irFunction.name
             returnType = irFunction.returnType
+            isFakeOverride = false
         }.apply {
             copyParametersWithErasure(this@addAbstractMethodStub, irFunction, needsArgumentBoxing)
         }

compiler/ir/backend.jvm/src/org/jetbrains/kotlin/backend/jvm/lower/CallableReferenceLowering.kt

@@ -153,6 +153,7 @@ internal class CallableReferenceLowering(private val context: JvmBackendContext)
 
         val fakeOverrideReceiverField = functionReferenceClass.addField {
             name = receiverFieldFromSuper.name
+            isFakeOverride = true
             origin = IrDeclarationOrigin.FAKE_OVERRIDE
             type = receiverFieldFromSuper.type
             isFinal = receiverFieldFromSuper.isFinal

compiler/ir/backend.jvm/src/org/jetbrains/kotlin/backend/jvm/lower/GenerateMultifileFacades.kt

@@ -34,6 +34,7 @@ import org.jetbrains.kotlin.ir.declarations.impl.IrFileImpl
 import org.jetbrains.kotlin.ir.expressions.*
 import org.jetbrains.kotlin.ir.expressions.impl.IrCallImpl
 import org.jetbrains.kotlin.ir.expressions.impl.IrClassReferenceImpl
+import org.jetbrains.kotlin.ir.types.defaultType
 import org.jetbrains.kotlin.ir.types.typeWith
 import org.jetbrains.kotlin.ir.util.*
 import org.jetbrains.kotlin.ir.visitors.IrElementTransformer
@@ -215,19 +216,21 @@ private fun IrSimpleFunction.createMultifileDelegateIfNeeded(
 
     val function = buildFun {
         updateFrom(target)
-        origin = if (shouldGeneratePartHierarchy) IrDeclarationOrigin.FAKE_OVERRIDE else JvmLoweredDeclarationOrigin.MULTIFILE_BRIDGE
+        isFakeOverride = shouldGeneratePartHierarchy
         name = target.name
     }
 
     function.copyParameterDeclarationsFrom(target)
-    function.returnType = target.returnType
+    function.returnType = target.returnType.substitute(target.typeParameters, function.typeParameters.map { it.defaultType })
     function.parent = facadeClass
-    function.annotations = target.annotations
+    function.annotations = target.annotations.map { it.deepCopyWithSymbols() }
 
     if (shouldGeneratePartHierarchy) {
+        function.origin = IrDeclarationOrigin.FAKE_OVERRIDE
         function.body = null
         function.overriddenSymbols = listOf(symbol)
     } else {
+        function.origin = JvmLoweredDeclarationOrigin.MULTIFILE_BRIDGE
         function.overriddenSymbols = overriddenSymbols.toList()
         function.body = context.createIrBuilder(function.symbol).irBlockBody {
             +irReturn(irCall(target).also { call ->

compiler/ir/backend.jvm/src/org/jetbrains/kotlin/backend/jvm/lower/PropertyReferenceLowering.kt

@@ -139,6 +139,7 @@ internal class PropertyReferenceLowering(val context: JvmBackendContext) : Class
             name = method.name
             returnType = method.returnType
             visibility = method.visibility
+            isFakeOverride = true
             origin = IrDeclarationOrigin.FAKE_OVERRIDE
         }.apply {
             overriddenSymbols += method.symbol
@@ -290,6 +291,7 @@ internal class PropertyReferenceLowering(val context: JvmBackendContext) : Class
 
                 val receiverField = referenceClass.addField {
                     name = backingFieldFromSuper.name
+                    isFakeOverride = true
                     origin = IrDeclarationOrigin.FAKE_OVERRIDE
                     type = backingFieldFromSuper.type
                     isFinal = backingFieldFromSuper.isFinal

compiler/ir/backend.jvm/src/org/jetbrains/kotlin/backend/jvm/lower/inlineclasses/MemoizedInlineClassReplacements.kt

@@ -146,7 +146,7 @@ class MemoizedInlineClassReplacements {
         }
 
     private fun createStaticReplacement(function: IrFunction): IrSimpleFunction =
-        buildReplacement(function, JvmLoweredDeclarationOrigin.STATIC_INLINE_CLASS_REPLACEMENT) {
+        buildReplacement(function, JvmLoweredDeclarationOrigin.STATIC_INLINE_CLASS_REPLACEMENT, noFakeOverride = true) {
             val newValueParameters = ArrayList<IrValueParameter>()
             for ((index, parameter) in function.explicitParameters.withIndex()) {
                 newValueParameters += when (parameter) {
@@ -171,7 +171,12 @@ class MemoizedInlineClassReplacements {
             valueParameters = newValueParameters
         }
 
-    private fun buildReplacement(function: IrFunction, replacementOrigin: IrDeclarationOrigin, body: IrFunctionImpl.() -> Unit) =
+    private fun buildReplacement(
+        function: IrFunction,
+        replacementOrigin: IrDeclarationOrigin,
+        noFakeOverride: Boolean = false,
+        body: IrFunctionImpl.() -> Unit
+    ) =
         buildFunWithDescriptorForInlining(function.descriptor) {
             updateFrom(function)
             origin = if (function.origin == IrDeclarationOrigin.GENERATED_INLINE_CLASS_MEMBER) {
@@ -179,6 +184,9 @@ class MemoizedInlineClassReplacements {
             } else {
                 replacementOrigin
             }
+            if (noFakeOverride) {
+                isFakeOverride = false
+            }
             name = mangledNameFor(function)
             returnType = function.returnType
         }.apply {

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/builders/declarations/IrFieldBuilder.kt

@@ -16,6 +16,7 @@ class IrFieldBuilder : IrDeclarationBuilder() {
     var isFinal: Boolean = false
     var isExternal: Boolean = false
     var isStatic: Boolean = false
+    var isFakeOverride: Boolean = false
     var metadata: MetadataSource.Property? = null
 
     fun updateFrom(from: IrField) {
@@ -25,6 +26,7 @@ class IrFieldBuilder : IrDeclarationBuilder() {
         isFinal = from.isFinal
         isExternal = from.isExternal
         isStatic = from.isStatic
+        isFakeOverride = from.isFakeOverride
         metadata = from.metadata
     }
 }

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/builders/declarations/IrFunctionBuilder.kt

@@ -27,6 +27,8 @@ class IrFunctionBuilder : IrDeclarationBuilder() {
 
     var isPrimary: Boolean = false
 
+    var isFakeOverride: Boolean = false
+
     fun updateFrom(from: IrFunction) {
         super.updateFrom(from)
 
@@ -39,6 +41,7 @@ class IrFunctionBuilder : IrDeclarationBuilder() {
             isTailrec = from.isTailrec
             isSuspend = from.isSuspend
             isOperator = from.isOperator
+            isFakeOverride = from.isFakeOverride
         } else {
             modality = Modality.FINAL
             isTailrec = false

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/builders/declarations/IrPropertyBuilder.kt

@@ -16,4 +16,5 @@ class IrPropertyBuilder : IrDeclarationBuilder() {
     var isDelegated: Boolean = false
     var isExternal: Boolean = false
     var isExpect: Boolean = false
+    var isFakeOverride: Boolean = false
 }