Fix IR declaration parents.

- Reparent declarations in FileClassLowering, InterfaceLowering,
  StaticDefaultFunctionsLowering, EnumClassLowering, and
  RenameFieldsLowering
- Set correspondingPropertySymbol in MoveCompanionObjectFieldsLowering
- Reparent field initializers in MoveCompanionObjectFieldsLowering and
  EnumClassLowering
- Ensure that parents are unique in PropertiesLowering
- Set declaration parent in SharedVariableManager
- Set field declaration parents in CallableReferenceLowering
- Set declaration parents in FunctionNVarargInvokeLowering
- Set declaration parents for external declaration fields

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

@@ -8,6 +8,7 @@ package org.jetbrains.kotlin.backend.common.lower
 import org.jetbrains.kotlin.backend.common.BackendContext
 import org.jetbrains.kotlin.backend.common.FileLoweringPass
 import org.jetbrains.kotlin.backend.common.descriptors.WrappedSimpleFunctionDescriptor
+import org.jetbrains.kotlin.backend.common.ir.copyTo
 import org.jetbrains.kotlin.descriptors.ClassKind
 import org.jetbrains.kotlin.descriptors.Modality
 import org.jetbrains.kotlin.descriptors.Visibilities
@@ -80,7 +81,7 @@ class PropertiesLowering(
         ).apply {
             descriptor.bind(this)
 
-            extensionReceiverParameter = declaration.getter?.extensionReceiverParameter
+            extensionReceiverParameter = declaration.getter?.extensionReceiverParameter?.copyTo(this)
 
             body = IrBlockBodyImpl(-1, -1)
 

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

@@ -106,7 +106,7 @@ class SharedVariablesLowering(val context: BackendContext) : FunctionLoweringPas
                     if (declaration !in sharedVariables) return declaration
 
                     val newDeclaration = context.sharedVariablesManager.declareSharedVariable(declaration)
-                    newDeclaration.parent = irFunction
+                    newDeclaration.parent = declaration.parent
                     transformedSymbols[declaration.symbol] = newDeclaration.symbol
 
                     return context.sharedVariablesManager.defineSharedValue(declaration, newDeclaration)

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

@@ -193,6 +193,7 @@ class JvmSharedVariablesManager(
         ).apply {
             (descriptor as WrappedVariableDescriptor).bind(this)
             initializer = refConstructorCall
+            parent = originalDeclaration.parent
         }
     }
 

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

@@ -450,6 +450,7 @@ internal class CallableReferenceLowering(val context: JvmBackendContext) : FileL
                 visibility = JavaVisibilities.PACKAGE_VISIBILITY
                 isFinal = true
             }.also {
+                it.parent = functionReferenceClass
                 functionReferenceClass.declarations.add(it)
             }
 

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

@@ -153,7 +153,7 @@ private class EnumClassLowering(val context: JvmBackendContext) : ClassLoweringP
                     }
                 })
 
-                body = enumConstructor.body // will be transformed later
+                body = enumConstructor.body?.patchDeclarationParents(this)
 
                 loweredEnumConstructors[enumConstructor.symbol] = this
                 metadata = enumConstructor.metadata
@@ -219,7 +219,9 @@ private class EnumClassLowering(val context: JvmBackendContext) : ClassLoweringP
             context.declarationFactory.getFieldForEnumEntry(
                 enumEntry, (enumEntry.correspondingClass ?: enumEntry.parentAsClass).defaultType
             ).also {
-                it.initializer = IrExpressionBodyImpl(enumEntry.initializerExpression!!)
+                it.initializer = IrExpressionBodyImpl(
+                    enumEntry.initializerExpression!!.patchDeclarationParents(it)
+                )
                 it.annotations.addAll(enumEntry.annotations)
                 enumEntryFields.add(it)
                 enumEntriesByField[it] = enumEntry

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

@@ -26,10 +26,7 @@ import org.jetbrains.kotlin.descriptors.ClassKind
 import org.jetbrains.kotlin.descriptors.Modality
 import org.jetbrains.kotlin.descriptors.Visibilities
 import org.jetbrains.kotlin.fileClasses.JvmFileClassUtil
-import org.jetbrains.kotlin.ir.declarations.IrClass
+import org.jetbrains.kotlin.ir.declarations.*
-import org.jetbrains.kotlin.ir.declarations.IrDeclaration
-import org.jetbrains.kotlin.ir.declarations.IrDeclarationOrigin
-import org.jetbrains.kotlin.ir.declarations.IrFile
 import org.jetbrains.kotlin.ir.declarations.impl.IrClassImpl
 import org.jetbrains.kotlin.ir.symbols.impl.IrClassSymbolImpl
 import org.jetbrains.kotlin.psi2ir.PsiSourceManager
@@ -93,8 +90,14 @@ private class FileClassLowering(val context: JvmBackendContext) : FileLoweringPa
             parent = irFile
             declarations.addAll(fileClassMembers)
             createImplicitParameterDeclarationWithWrappedDescriptor()
-            // TODO: figure out why reparenting leads to failing tests.
+            fileClassMembers.forEach {
-            // fileClassMembers.forEach { it.parent = this }
+                it.parent = this
+                if (it is IrProperty) {
+                    it.getter?.let { it.parent = this }
+                    it.setter?.let { it.parent = this }
+                    it.backingField?.let { it.parent = this }
+                }
+            }
             metadata = irFile.metadata
 
             val partClassType = AsmUtil.asmTypeByFqNameWithoutInnerClasses(fileClassInfo.fileClassFqName)

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

@@ -8,6 +8,7 @@ package org.jetbrains.kotlin.backend.jvm.lower
 import org.jetbrains.kotlin.backend.common.ClassLoweringPass
 import org.jetbrains.kotlin.backend.common.descriptors.WrappedSimpleFunctionDescriptor
 import org.jetbrains.kotlin.backend.common.descriptors.WrappedValueParameterDescriptor
+import org.jetbrains.kotlin.backend.common.ir.copyTo
 import org.jetbrains.kotlin.backend.common.lower.createIrBuilder
 import org.jetbrains.kotlin.backend.common.lower.irIfThen
 import org.jetbrains.kotlin.backend.common.phaser.makeIrFilePhase
@@ -71,7 +72,8 @@ private class FunctionNVarargInvokeLowering(var context: JvmBackendContext) : Cl
             isSuspend = false
         ).apply {
             descriptor.bind(this)
-            dispatchReceiverParameter = irClass.thisReceiver
+            parent = irClass
+            dispatchReceiverParameter = irClass.thisReceiver?.copyTo(this)
             val varargParameterDescriptor = WrappedValueParameterDescriptor()
             val varargParam = IrValueParameterImpl(
                 UNDEFINED_OFFSET, UNDEFINED_OFFSET,
@@ -86,6 +88,7 @@ private class FunctionNVarargInvokeLowering(var context: JvmBackendContext) : Cl
             ).apply {
                 varargParameterDescriptor.bind(this)
             }
+            varargParam.parent = this
             valueParameters.add(varargParam)
             val irBuilder = context.createIrBuilder(symbol, UNDEFINED_OFFSET, UNDEFINED_OFFSET)
             body = irBuilder.irBlockBody(UNDEFINED_OFFSET, UNDEFINED_OFFSET) {

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

@@ -22,6 +22,7 @@ import org.jetbrains.kotlin.ir.declarations.impl.IrFunctionImpl
 import org.jetbrains.kotlin.ir.symbols.impl.IrSimpleFunctionSymbolImpl
 import org.jetbrains.kotlin.ir.types.IrType
 import org.jetbrains.kotlin.ir.util.isInterface
+import org.jetbrains.kotlin.ir.util.patchDeclarationParents
 import org.jetbrains.kotlin.ir.visitors.IrElementTransformerVoid
 import org.jetbrains.kotlin.ir.visitors.transformChildrenVoid
 import org.jetbrains.kotlin.name.Name
@@ -49,7 +50,7 @@ private class InterfaceLowering(val context: JvmBackendContext) : IrElementTrans
             if (function.modality != Modality.ABSTRACT && function.origin != IrDeclarationOrigin.FAKE_OVERRIDE) {
                 val element = context.declarationFactory.getDefaultImplsFunction(function)
                 members.add(element)
-                element.body = function.body
+                element.body = function.body?.patchDeclarationParents(element)
                 function.body = null
                 //TODO reset modality to abstract
             }
@@ -111,7 +112,9 @@ internal fun createStaticFunctionWithReceivers(
         val mapping: Map<IrValueParameter, IrValueParameter> =
             (listOfNotNull(oldFunction.dispatchReceiverParameter, oldFunction.extensionReceiverParameter) + oldFunction.valueParameters)
                 .zip(valueParameters).toMap()
-        body = oldFunction.body?.transform(VariableRemapper(mapping), null)
+        body = oldFunction.body
+            ?.transform(VariableRemapper(mapping), null)
+            ?.patchDeclarationParents(this)
 
         metadata = oldFunction.metadata
     }

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

@@ -26,10 +26,7 @@ import org.jetbrains.kotlin.ir.symbols.IrFieldSymbol
 import org.jetbrains.kotlin.ir.symbols.impl.IrAnonymousInitializerSymbolImpl
 import org.jetbrains.kotlin.ir.symbols.impl.IrFieldSymbolImpl
 import org.jetbrains.kotlin.ir.symbols.impl.IrVariableSymbolImpl
-import org.jetbrains.kotlin.ir.util.hasAnnotation
+import org.jetbrains.kotlin.ir.util.*
-import org.jetbrains.kotlin.ir.util.isAnnotationClass
-import org.jetbrains.kotlin.ir.util.isInterface
-import org.jetbrains.kotlin.ir.util.isObject
 import org.jetbrains.kotlin.ir.visitors.IrElementTransformerVoid
 import org.jetbrains.kotlin.ir.visitors.transformChildrenVoid
 import org.jetbrains.kotlin.load.java.JvmAbi.JVM_FIELD_ANNOTATION_FQ_NAME
@@ -188,11 +185,9 @@ private class MoveCompanionObjectFieldsLowering(val context: CommonBackendContex
         }
         val oldInitializer = oldField.initializer
         if (oldInitializer != null) {
-            field.initializer = oldInitializer.replaceThisByStaticReference(
+            field.initializer = oldInitializer
-                context,
+                .replaceThisByStaticReference(context, propertyParent, propertyParent.thisReceiver!!)
-                propertyParent,
+                .patchDeclarationParents(field) as IrExpressionBody
-                propertyParent.thisReceiver!!
-            ) as IrExpressionBody
         }
 
         return field

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

@@ -109,8 +109,9 @@ internal class PropertyReferenceLowering(val context: JvmBackendContext) : Class
         val parent = expression.propertyContainerChild?.parent
         val context = this@PropertyReferenceLowering.context
         return when {
-            // FileClassLowering creates a class to which all package-level declarations are moved. However, it does not
+            // FileClassLowering creates a class to which all package-level declarations are moved. However, there
-            // fix the declarations' parents (yet), which is why we check for both a file class and a package fragment.
+            // can still be external declarations at the package level, which is why we check for both a file class
+            // and a package fragment.
             parent is IrPackageFragment || (parent is IrClass && parent.origin == IrDeclarationOrigin.FILE_CLASS) ->
                 irCall(context.ir.symbols.getOrCreateKotlinPackage).apply {
                     putValueArgument(0, expression.parentJavaClassReference)

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

@@ -23,6 +23,7 @@ import org.jetbrains.kotlin.ir.expressions.impl.IrSetFieldImpl
 import org.jetbrains.kotlin.ir.symbols.IrFieldSymbol
 import org.jetbrains.kotlin.ir.symbols.impl.IrFieldSymbolImpl
 import org.jetbrains.kotlin.ir.util.hasAnnotation
+import org.jetbrains.kotlin.ir.util.patchDeclarationParents
 import org.jetbrains.kotlin.ir.visitors.IrElementTransformerVoid
 import org.jetbrains.kotlin.ir.visitors.IrElementVisitorVoid
 import org.jetbrains.kotlin.ir.visitors.acceptChildrenVoid
@@ -97,7 +98,9 @@ private class FieldRenamer(private val newNames: Map<IrField, Name>) : IrElement
         ).also {
             descriptor.bind(it)
             it.parent = declaration.parent
-            it.initializer = declaration.initializer?.transform(this, null)
+            it.initializer = declaration.initializer
+                ?.transform(this, null)
+                ?.patchDeclarationParents(it)
             it.metadata = declaration.metadata
 
             newSymbols[declaration] = symbol

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/util/PatchDeclarationParents.kt

@@ -54,10 +54,15 @@ class PatchDeclarationParentsVisitor() : IrElementVisitorVoid {
     }
 
     override fun visitProperty(declaration: IrProperty) {
-        declaration.getter?.let { it.correspondingProperty = declaration }
+        declaration.getter?.let {
-        declaration.setter?.let { it.correspondingProperty = declaration }
+            it.correspondingPropertySymbol = declaration.symbol
-        declaration.backingField?.let { it.correspondingProperty = declaration }
+        }
-
+        declaration.setter?.let {
+            it.correspondingPropertySymbol = declaration.symbol
+        }
+        declaration.backingField?.let {
+            it.correspondingPropertySymbol = declaration.symbol
+        }
         super.visitProperty(declaration)
     }