No use of "by ..Scope.Empty"

compiler/frontend.java/src/org/jetbrains/kotlin/synthetic/JavaSyntheticPropertiesScope.kt

@@ -27,8 +27,8 @@ import org.jetbrains.kotlin.incremental.components.NoLookupLocation
 import org.jetbrains.kotlin.load.java.JvmAbi
 import org.jetbrains.kotlin.name.Name
 import org.jetbrains.kotlin.resolve.DescriptorUtils
+import org.jetbrains.kotlin.resolve.scopes.BaseImportingScope
 import org.jetbrains.kotlin.resolve.scopes.DescriptorKindFilter
-import org.jetbrains.kotlin.resolve.scopes.ImportingScope
 import org.jetbrains.kotlin.resolve.scopes.LexicalScope
 import org.jetbrains.kotlin.resolve.scopes.utils.collectSyntheticExtensionProperties
 import org.jetbrains.kotlin.storage.StorageManager
@@ -69,7 +69,7 @@ interface SyntheticJavaPropertyDescriptor : PropertyDescriptor {
     }
 }
 
-class JavaSyntheticPropertiesScope(storageManager: StorageManager) : ImportingScope by ImportingScope.Empty {
+class JavaSyntheticPropertiesScope(storageManager: StorageManager) : BaseImportingScope(null) {
     private val syntheticPropertyInClass = storageManager.createMemoizedFunctionWithNullableValues<Pair<ClassDescriptor, Name>, PropertyDescriptor> { pair ->
         syntheticPropertyInClassNotCached(pair.first, pair.second)
     }

compiler/frontend.java/src/org/jetbrains/kotlin/synthetic/SamAdapterFunctionsScope.kt

@@ -26,8 +26,8 @@ import org.jetbrains.kotlin.load.java.typeEnhacement.enhanceSignature
 import org.jetbrains.kotlin.name.Name
 import org.jetbrains.kotlin.resolve.DescriptorUtils
 import org.jetbrains.kotlin.resolve.descriptorUtil.parentsWithSelf
+import org.jetbrains.kotlin.resolve.scopes.BaseImportingScope
 import org.jetbrains.kotlin.resolve.scopes.DescriptorKindFilter
-import org.jetbrains.kotlin.resolve.scopes.ImportingScope
 import org.jetbrains.kotlin.storage.StorageManager
 import org.jetbrains.kotlin.types.*
 import org.jetbrains.kotlin.utils.Printer
@@ -38,7 +38,7 @@ interface SamAdapterExtensionFunctionDescriptor : FunctionDescriptor {
     val sourceFunction: FunctionDescriptor
 }
 
-class SamAdapterFunctionsScope(storageManager: StorageManager) : ImportingScope by ImportingScope.Empty {
+class SamAdapterFunctionsScope(storageManager: StorageManager) : BaseImportingScope(null) {
     private val extensionForFunction = storageManager.createMemoizedFunctionWithNullableValues<FunctionDescriptor, FunctionDescriptor> { function ->
         extensionForFunctionNotCached(function)
     }

compiler/frontend/src/org/jetbrains/kotlin/resolve/AllUnderImportsScope.kt

@@ -21,11 +21,11 @@ import org.jetbrains.kotlin.descriptors.DeclarationDescriptor
 import org.jetbrains.kotlin.descriptors.PackageViewDescriptor
 import org.jetbrains.kotlin.incremental.components.LookupLocation
 import org.jetbrains.kotlin.name.Name
+import org.jetbrains.kotlin.resolve.scopes.BaseImportingScope
 import org.jetbrains.kotlin.resolve.scopes.DescriptorKindFilter
-import org.jetbrains.kotlin.resolve.scopes.ImportingScope
 import org.jetbrains.kotlin.utils.Printer
 
-class AllUnderImportsScope(descriptor: DeclarationDescriptor) : ImportingScope by ImportingScope.Empty {
+class AllUnderImportsScope(descriptor: DeclarationDescriptor) : BaseImportingScope(null) {
     private val scopes = if (descriptor is ClassDescriptor) {
         listOf(descriptor.staticScope, descriptor.unsubstitutedInnerClassesScope)
     }

compiler/frontend/src/org/jetbrains/kotlin/resolve/SingleImportScope.kt

@@ -19,11 +19,11 @@ package org.jetbrains.kotlin.resolve
 import org.jetbrains.kotlin.descriptors.*
 import org.jetbrains.kotlin.incremental.components.LookupLocation
 import org.jetbrains.kotlin.name.Name
+import org.jetbrains.kotlin.resolve.scopes.BaseImportingScope
 import org.jetbrains.kotlin.resolve.scopes.DescriptorKindFilter
-import org.jetbrains.kotlin.resolve.scopes.ImportingScope
 import org.jetbrains.kotlin.utils.Printer
 
-class SingleImportScope(private val aliasName: Name, private val descriptors: Collection<DeclarationDescriptor>) : ImportingScope by ImportingScope.Empty {
+class SingleImportScope(private val aliasName: Name, private val descriptors: Collection<DeclarationDescriptor>) : BaseImportingScope(null) {
     override fun getContributedClassifier(name: Name, location: LookupLocation)
             = if (name == aliasName) descriptors.filterIsInstance<ClassifierDescriptor>().singleOrNull() else null
 

compiler/frontend/src/org/jetbrains/kotlin/resolve/lazy/FileScopeProviderImpl.kt

@@ -29,15 +29,17 @@ import org.jetbrains.kotlin.resolve.NoSubpackagesInPackageScope
 import org.jetbrains.kotlin.resolve.QualifiedExpressionResolver
 import org.jetbrains.kotlin.resolve.TemporaryBindingTrace
 import org.jetbrains.kotlin.resolve.bindingContextUtil.recordScope
+import org.jetbrains.kotlin.resolve.scopes.BaseLexicalScope
 import org.jetbrains.kotlin.resolve.scopes.ImportingScope
 import org.jetbrains.kotlin.resolve.scopes.LexicalScope
 import org.jetbrains.kotlin.resolve.scopes.utils.memberScopeAsImportingScope
 import org.jetbrains.kotlin.resolve.scopes.utils.withParent
 import org.jetbrains.kotlin.storage.StorageManager
 import org.jetbrains.kotlin.storage.getValue
+import org.jetbrains.kotlin.utils.Printer
 import org.jetbrains.kotlin.utils.sure
 
-public class FileScopeProviderImpl(
+public open class FileScopeProviderImpl(
         private val topLevelDescriptorProvider: TopLevelDescriptorProvider,
         private val storageManager: StorageManager,
         private val moduleDescriptor: ModuleDescriptor,
@@ -108,12 +110,13 @@ public class FileScopeProviderImpl(
 
         scope = LazyImportScope(scope, packageFragment, aliasImportResolver, LazyImportScope.FilteringKind.ALL, "Alias imports in $debugName")
 
-        val lexicalScope = object : LexicalScope by LexicalScope.Empty {
+        val lexicalScope = object : BaseLexicalScope(scope) {
-            override val parent: LexicalScope?
-                get() = scope
-
             override val ownerDescriptor: DeclarationDescriptor
                 get() = packageFragment
+
+            override fun printStructure(p: Printer) {
+                p.println("File top-level scope (empty)")
+            }
         }
 
         bindingTrace.recordScope(lexicalScope, file)

compiler/frontend/src/org/jetbrains/kotlin/resolve/scopes/utils/ScopeUtils.kt

@@ -327,7 +327,7 @@ fun ImportingScope.withParent(newParent: ImportingScope?): ImportingScope {
 
 fun LexicalScope.replaceImportingScopes(importingScopeChain: ImportingScope?): LexicalScope {
     return if (this is ImportingScope)
-        importingScopeChain ?: LexicalScope.Empty
+        importingScopeChain ?: ImportingScope.Empty
     else
         LexicalScopeWrapper(this, importingScopeChain)
 }

core/descriptors/src/org/jetbrains/kotlin/resolve/scopes/ExplicitImportsScope.kt

@@ -22,7 +22,7 @@ import org.jetbrains.kotlin.name.Name
 import org.jetbrains.kotlin.utils.Printer
 import org.jetbrains.kotlin.utils.addToStdlib.firstIsInstanceOrNull
 
-public class ExplicitImportsScope(private val descriptors: Collection<DeclarationDescriptor>) : ImportingScope by ImportingScope.Empty {
+public class ExplicitImportsScope(private val descriptors: Collection<DeclarationDescriptor>) : BaseImportingScope(null) {
     override fun getContributedClassifier(name: Name, location: LookupLocation)
             = descriptors.filter { it.getName() == name }.firstIsInstanceOrNull<ClassifierDescriptor>()
 

core/descriptors/src/org/jetbrains/kotlin/resolve/scopes/Scopes.kt

@@ -48,30 +48,6 @@ interface LexicalScope {
     fun getContributedFunctions(name: Name, location: LookupLocation): Collection<FunctionDescriptor>
 
     fun printStructure(p: Printer)
-
-    object Empty : LexicalScope {
-        override val parent: LexicalScope?
-            get() = null
-
-        override val ownerDescriptor: DeclarationDescriptor
-            get() = throw UnsupportedOperationException()
-
-        override val isOwnerDescriptorAccessibleByLabel: Boolean
-            get() = false
-
-        override val implicitReceiver: ReceiverParameterDescriptor?
-            get() = null
-
-        override fun getContributedDescriptors(kindFilter: DescriptorKindFilter, nameFilter: (Name) -> Boolean): Collection<DeclarationDescriptor> = emptyList()
-
-        override fun getContributedClassifier(name: Name, location: LookupLocation): ClassifierDescriptor? = null
-
-        override fun getContributedVariables(name: Name, location: LookupLocation): Collection<VariableDescriptor> = emptyList()
-
-        override fun getContributedFunctions(name: Name, location: LookupLocation): Collection<FunctionDescriptor> = emptyList()
-
-        override fun printStructure(p: Printer) = throw UnsupportedOperationException()
-    }
 }
 
 // TODO: common base interface instead direct inheritance
@@ -94,15 +70,49 @@ interface ImportingScope : LexicalScope {
     fun getContributedSyntheticExtensionProperties(receiverTypes: Collection<KotlinType>): Collection<PropertyDescriptor>
     fun getContributedSyntheticExtensionFunctions(receiverTypes: Collection<KotlinType>): Collection<FunctionDescriptor>
 
-    object Empty : ImportingScope, LexicalScope by LexicalScope.Empty {
+    object Empty : BaseImportingScope(null) {
-        override fun getContributedPackage(name: Name) = null
+        override fun printStructure(p: Printer) {
-
+            p.println("ImportingScope.Empty")
-        override fun getContributedSyntheticExtensionProperties(receiverTypes: Collection<KotlinType>, name: Name, location: LookupLocation): Collection<PropertyDescriptor> = emptyList()
+        }
-
-        override fun getContributedSyntheticExtensionFunctions(receiverTypes: Collection<KotlinType>, name: Name, location: LookupLocation): Collection<FunctionDescriptor> = emptyList()
-
-        override fun getContributedSyntheticExtensionProperties(receiverTypes: Collection<KotlinType>): Collection<PropertyDescriptor> = emptyList()
-
-        override fun getContributedSyntheticExtensionFunctions(receiverTypes: Collection<KotlinType>): Collection<FunctionDescriptor> = emptyList()
     }
 }
+
+abstract class BaseLexicalScope(override val parent: LexicalScope?) : LexicalScope {
+    override val isOwnerDescriptorAccessibleByLabel: Boolean
+        get() = false
+
+    override val implicitReceiver: ReceiverParameterDescriptor?
+        get() = null
+
+    override fun getContributedDescriptors(kindFilter: DescriptorKindFilter, nameFilter: (Name) -> Boolean): Collection<DeclarationDescriptor> = emptyList()
+
+    override fun getContributedClassifier(name: Name, location: LookupLocation): ClassifierDescriptor? = null
+
+    override fun getContributedVariables(name: Name, location: LookupLocation): Collection<VariableDescriptor> = emptyList()
+
+    override fun getContributedFunctions(name: Name, location: LookupLocation): Collection<FunctionDescriptor> = emptyList()
+}
+
+abstract class BaseImportingScope(parent: ImportingScope?) : BaseLexicalScope(parent), ImportingScope {
+    override val parent: ImportingScope?
+        get() = super.parent as ImportingScope?
+
+    override val ownerDescriptor: DeclarationDescriptor
+        get() = throw UnsupportedOperationException()
+
+    override final val isOwnerDescriptorAccessibleByLabel: Boolean
+        get() = false
+
+    override final val implicitReceiver: ReceiverParameterDescriptor?
+        get() = null
+
+    override fun getContributedPackage(name: Name): PackageViewDescriptor? = null
+
+    override fun getContributedSyntheticExtensionProperties(receiverTypes: Collection<KotlinType>, name: Name, location: LookupLocation): Collection<PropertyDescriptor> = emptyList()
+
+    override fun getContributedSyntheticExtensionFunctions(receiverTypes: Collection<KotlinType>, name: Name, location: LookupLocation): Collection<FunctionDescriptor> = emptyList()
+
+    override fun getContributedSyntheticExtensionProperties(receiverTypes: Collection<KotlinType>): Collection<PropertyDescriptor> = emptyList()
+
+    override fun getContributedSyntheticExtensionFunctions(receiverTypes: Collection<KotlinType>): Collection<FunctionDescriptor> = emptyList()
+}