Add NotAugmentedXyzElementImpl implements AugmentedXyzElement.

So, that we don't have to copy all class members for 99% cases when
there are no augmentaitons.

Change-Id: I5c225905a0460ce5162543553e207a2d4412ecb9
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/313082
Commit-Queue: Konstantin Shcheglov <scheglov@google.com>
Reviewed-by: Samuel Rawlins <srawlins@google.com>

pkg/analyzer/lib/dart/element/element.dart

@@ -1644,13 +1644,6 @@ abstract class InterfaceElement
   @override
   InterfaceType get thisType;
 
-  /// The unnamed constructor declared directly in this class.
-  ///
-  /// If the class does not declare any constructors, a synthetic default
-  /// constructor will be returned.
-  /// TODO(scheglov) Deprecate and remove it.
-  ConstructorElement? get unnamedConstructor;
-
   /// The field (synthetic or explicit) defined directly in this class or
   /// augmentation that has the given [name].
   /// TODO(scheglov) Deprecate and remove it.
@@ -1666,11 +1659,6 @@ abstract class InterfaceElement
   /// TODO(scheglov) Deprecate and remove it.
   MethodElement? getMethod(String name);
 
-  /// The constructor defined directly in this class or augmentation
-  /// that has the given [name].
-  /// TODO(scheglov) Deprecate and remove it.
-  ConstructorElement? getNamedConstructor(String name);
-
   /// The setter (synthetic or explicit) defined directly in this class or
   /// augmentation that has the given [name].
   /// TODO(scheglov) Deprecate and remove it.
@@ -2255,6 +2243,18 @@ abstract class NamedInstanceElement
   @override
   AugmentedNamedInstanceElement get augmented;
 
+  /// The unnamed constructor declared directly in this class.
+  ///
+  /// If the class does not declare any constructors, a synthetic default
+  /// constructor will be returned.
+  /// TODO(scheglov) Deprecate and remove it.
+  ConstructorElement? get unnamedConstructor;
+
+  /// The constructor defined directly in this class or augmentation
+  /// that has the given [name].
+  /// TODO(scheglov) Deprecate and remove it.
+  ConstructorElement? getNamedConstructor(String name);
+
   /// Create the [DartType] for this element with the given [typeArguments]
   /// and [nullabilitySuffix].
   DartType instantiate({

pkg/analyzer/lib/src/dart/analysis/driver.dart

@@ -87,7 +87,7 @@ import 'package:analyzer/src/utilities/uri_cache.dart';
 /// TODO(scheglov) Clean up the list of implicitly analyzed files.
 class AnalysisDriver implements AnalysisDriverGeneric {
   /// The version of data format, should be incremented on every format change.
-  static const int DATA_VERSION = 283;
+  static const int DATA_VERSION = 284;
 
   /// The number of exception contexts allowed to write. Once this field is
   /// zero, we stop writing any new exception contexts in this process.

pkg/analyzer/lib/src/dart/element/element.dart

@@ -232,8 +232,8 @@ class ClassAugmentationElementImpl extends InterfaceAugmentationElementImpl
 class ClassElementImpl extends ClassOrMixinElementImpl
     with ClassOrAugmentationElementMixin
     implements ClassElement {
-  @override
-  final AugmentedClassElementImpl augmented = AugmentedClassElementImpl();
+  late AugmentedClassElement augmentedInternal =
+      NotAugmentedClassElementImpl(this);
 
   /// Initialize a newly created class element to have the given [name] at the
   /// given [offset] in the file that contains the declaration of this element.
@@ -285,6 +285,12 @@ class ClassElementImpl extends ClassOrMixinElementImpl
     return null;
   }
 
+  @override
+  AugmentedClassElement get augmented {
+    linkedData?.read(this);
+    return augmentedInternal;
+  }
+
   @override
   ClassElementImpl get augmentedDeclaration => this;
 
@@ -3637,7 +3643,7 @@ abstract class InterfaceElementImpl extends NamedInstanceElementImpl
   }
 
   @override
-  AugmentedInterfaceElementImpl get augmented {
+  AugmentedInterfaceElement get augmented {
     throw UnimplementedError();
   }
 
@@ -3691,11 +3697,6 @@ abstract class InterfaceElementImpl extends NamedInstanceElementImpl
     return _thisType!;
   }
 
-  @override
-  ConstructorElement? get unnamedConstructor {
-    return constructors.firstWhereOrNull((element) => element.name.isEmpty);
-  }
-
   @override
   FieldElement? getField(String name) {
     return fields.firstWhereOrNull((fieldElement) => name == fieldElement.name);
@@ -3712,15 +3713,6 @@ abstract class InterfaceElementImpl extends NamedInstanceElementImpl
     return methods.firstWhereOrNull((method) => method.name == methodName);
   }
 
-  @override
-  ConstructorElement? getNamedConstructor(String name) {
-    if (name == 'new') {
-      // A constructor declared as `C.new` is unnamed, and is modeled as such.
-      name = '';
-    }
-    return constructors.firstWhereOrNull((element) => element.name == name);
-  }
-
   @override
   PropertyAccessorElement? getSetter(String setterName) {
     return getSetterFromAccessors(setterName, accessors);
@@ -5095,15 +5087,15 @@ class MixinElementImpl extends ClassOrMixinElementImpl
   /// The list will be empty if this class is not a mixin declaration.
   late List<String> superInvokedNames;
 
-  final AugmentedMixinElementImpl augmentedInternal =
-      AugmentedMixinElementImpl();
+  late AugmentedMixinElement augmentedInternal =
+      NotAugmentedMixinElementImpl(this);
 
   /// Initialize a newly created class element to have the given [name] at the
   /// given [offset] in the file that contains the declaration of this element.
   MixinElementImpl(super.name, super.offset);
 
   @override
-  AugmentedMixinElementImpl get augmented {
+  AugmentedMixinElement get augmented {
     linkedData?.read(this);
     return augmentedInternal;
   }
@@ -5607,6 +5599,20 @@ abstract class NamedInstanceElementImpl extends InstanceElementImpl
     with NamedInstanceOrAugmentationElementMixin
     implements NamedInstanceElement {
   NamedInstanceElementImpl(super.name, super.nameOffset);
+
+  @override
+  ConstructorElement? get unnamedConstructor {
+    return constructors.firstWhereOrNull((element) => element.name.isEmpty);
+  }
+
+  @override
+  ConstructorElement? getNamedConstructor(String name) {
+    if (name == 'new') {
+      // A constructor declared as `C.new` is unnamed, and is modeled as such.
+      name = '';
+    }
+    return constructors.firstWhereOrNull((element) => element.name == name);
+  }
 }
 
 mixin NamedInstanceOrAugmentationElementMixin
@@ -5701,6 +5707,155 @@ abstract class NonParameterVariableElementImpl extends VariableElementImpl
   }
 }
 
+class NotAugmentedClassElementImpl extends NotAugmentedInterfaceElementImpl
+    implements AugmentedClassElement {
+  @override
+  final ClassElementImpl element;
+
+  NotAugmentedClassElementImpl(this.element);
+}
+
+class NotAugmentedEnumElementImpl extends NotAugmentedInterfaceElementImpl
+    implements AugmentedEnumElement {
+  @override
+  final EnumElementImpl element;
+
+  NotAugmentedEnumElementImpl(this.element);
+}
+
+class NotAugmentedExtensionElementImpl extends AugmentedInstanceElementImpl
+    implements AugmentedExtensionElement {
+  final ExtensionElementImpl element;
+
+  NotAugmentedExtensionElementImpl(this.element);
+}
+
+class NotAugmentedInlineClassElementImpl
+    extends NotAugmentedNamedInstanceElementImpl
+    implements AugmentedInlineClassElement {
+  @override
+  final InlineClassElementImpl element;
+
+  NotAugmentedInlineClassElementImpl(this.element);
+}
+
+abstract class NotAugmentedInstanceElementImpl
+    implements AugmentedInstanceElement {
+  @override
+  List<PropertyAccessorElement> get accessors {
+    return element.accessors;
+  }
+
+  InstanceElementImpl get element;
+
+  @override
+  List<FieldElement> get fields {
+    return element.fields;
+  }
+
+  @override
+  List<ElementAnnotation> get metadata {
+    return element.metadata;
+  }
+
+  @override
+  List<MethodElement> get methods {
+    return element.methods;
+  }
+
+  @override
+  FieldElement? getField(String name) {
+    for (final field in fields) {
+      if (field.name == name) {
+        return field;
+      }
+    }
+    return null;
+  }
+
+  @override
+  PropertyAccessorElement? getGetter(String name) {
+    for (final getter in accessors) {
+      if (getter.isGetter && getter.name == name) {
+        return getter;
+      }
+    }
+    return null;
+  }
+
+  @override
+  MethodElement? getMethod(String name) {
+    for (final method in methods) {
+      if (method.name == name) {
+        return method;
+      }
+    }
+    return null;
+  }
+
+  @override
+  PropertyAccessorElement? getSetter(String name) {
+    for (final setter in accessors) {
+      if (setter.isSetter && setter.name == name) {
+        return setter;
+      }
+    }
+    return null;
+  }
+}
+
+abstract class NotAugmentedInterfaceElementImpl
+    extends NotAugmentedNamedInstanceElementImpl
+    implements AugmentedInterfaceElement {
+  @override
+  InterfaceElementImpl get element;
+
+  @override
+  List<InterfaceType> get interfaces {
+    return element.interfaces;
+  }
+
+  @override
+  List<InterfaceType> get mixins {
+    return element.mixins;
+  }
+}
+
+class NotAugmentedMixinElementImpl extends NotAugmentedInterfaceElementImpl
+    implements AugmentedMixinElement {
+  @override
+  final MixinElementImpl element;
+
+  NotAugmentedMixinElementImpl(this.element);
+
+  @override
+  List<InterfaceType> get superclassConstraints {
+    return element.superclassConstraints;
+  }
+}
+
+abstract class NotAugmentedNamedInstanceElementImpl
+    extends NotAugmentedInstanceElementImpl
+    implements AugmentedNamedInstanceElement {
+  @override
+  List<ConstructorElement> get constructors {
+    return element.constructors;
+  }
+
+  @override
+  NamedInstanceElementImpl get element;
+
+  @override
+  ConstructorElement? get unnamedConstructor {
+    return element.unnamedConstructor;
+  }
+
+  @override
+  ConstructorElement? getNamedConstructor(String name) {
+    return element.getNamedConstructor(name);
+  }
+}
+
 /// A concrete implementation of a [ParameterElement].
 class ParameterElementImpl extends VariableElementImpl
     with ParameterElementMixin

pkg/analyzer/lib/src/summary2/bundle_reader.dart

@@ -151,8 +151,14 @@ class ClassElementLinkedData extends ElementLinkedData<ClassElementImpl> {
     element.interfaces = reader._readInterfaceTypeList();
     element.augmentation =
         reader.readElement() as ClassAugmentationElementImpl?;
-    element.augmented.mixins = reader._readInterfaceTypeList();
-    element.augmented.interfaces = reader._readInterfaceTypeList();
+
+    if (reader.readBool()) {
+      final augmented = AugmentedClassElementImpl();
+      element.augmentedInternal = augmented;
+      augmented.mixins = reader._readInterfaceTypeList();
+      augmented.interfaces = reader._readInterfaceTypeList();
+    }
+
     applyConstantOffsets?.perform();
   }
 }
@@ -1727,8 +1733,14 @@ class MixinElementLinkedData extends ElementLinkedData<MixinElementImpl> {
     element.interfaces = reader._readInterfaceTypeList();
     element.augmentation =
         reader.readElement() as MixinAugmentationElementImpl?;
-    element.augmented.superclassConstraints = reader._readInterfaceTypeList();
-    element.augmented.interfaces = reader._readInterfaceTypeList();
+
+    if (reader.readBool()) {
+      final augmented = AugmentedMixinElementImpl();
+      element.augmentedInternal = augmented;
+      augmented.superclassConstraints = reader._readInterfaceTypeList();
+      augmented.interfaces = reader._readInterfaceTypeList();
+    }
+
     applyConstantOffsets?.perform();
   }
 }
@@ -1782,6 +1794,10 @@ class ResolutionReader {
     return _elementFactory.libraryOfUri2(uri);
   }
 
+  bool readBool() {
+    return _reader.readBool();
+  }
+
   int readByte() {
     return _reader.readByte();
   }

pkg/analyzer/lib/src/summary2/bundle_writer.dart

@@ -182,8 +182,13 @@ class BundleWriter {
       _resolutionSink._writeTypeList(element.mixins);
       _resolutionSink._writeTypeList(element.interfaces);
       _resolutionSink.writeElement(element.augmentation);
-      _resolutionSink._writeTypeList(element.augmented.mixins);
-      _resolutionSink._writeTypeList(element.augmented.interfaces);
+      _resolutionSink.writeIfType<AugmentedClassElementImpl>(
+        element.augmented,
+        (augmented) {
+          _resolutionSink._writeTypeList(augmented.mixins);
+          _resolutionSink._writeTypeList(augmented.interfaces);
+        },
+      );
 
       if (!element.isMixinApplication) {
         var membersOffset = _sink.offset;
@@ -466,8 +471,13 @@ class BundleWriter {
       _resolutionSink._writeTypeList(element.superclassConstraints);
       _resolutionSink._writeTypeList(element.interfaces);
       _resolutionSink.writeElement(element.augmentation);
-      _resolutionSink._writeTypeList(element.augmented.superclassConstraints);
-      _resolutionSink._writeTypeList(element.augmented.interfaces);
+      _resolutionSink.writeIfType<AugmentedMixinElementImpl>(
+        element.augmented,
+        (augmented) {
+          _resolutionSink._writeTypeList(augmented.superclassConstraints);
+          _resolutionSink._writeTypeList(augmented.interfaces);
+        },
+      );
 
       _writeList(
         element.fields.where((e) => !e.isSynthetic).toList(),

pkg/analyzer/lib/src/summary2/data_writer.dart

@@ -121,6 +121,18 @@ class BufferedSink {
     addByte(byte);
   }
 
+  void writeIfType<T extends Object>(
+    Object? object,
+    void Function(T t) ifTrue,
+  ) {
+    if (object is T) {
+      writeBool(true);
+      ifTrue(object);
+    } else {
+      writeBool(false);
+    }
+  }
+
   void writeList<T>(List<T> items, void Function(T x) writeItem) {
     writeUInt30(items.length);
     for (var i = 0; i < items.length; i++) {

pkg/analyzer/lib/src/summary2/types_builder.dart

@@ -168,9 +168,12 @@ class TypesBuilder {
       node.implementsClause?.interfaces,
     );
 
-    final augmented = element.augmented;
-    augmented.mixins.addAll(element.mixins);
-    augmented.interfaces.addAll(element.interfaces);
+    if (element.augmentation != null) {
+      final augmented = AugmentedClassElementImpl();
+      element.augmentedInternal = augmented;
+      augmented.mixins.addAll(element.mixins);
+      augmented.interfaces.addAll(element.interfaces);
+    }
   }
 
   void _classTypeAlias(ClassTypeAlias node) {
@@ -373,9 +376,12 @@ class TypesBuilder {
       node.implementsClause?.interfaces,
     );
 
-    final augmented = element.augmented;
-    augmented.superclassConstraints.addAll(element.superclassConstraints);
-    augmented.interfaces.addAll(element.interfaces);
+    if (element.augmentation != null) {
+      final augmented = AugmentedMixinElementImpl();
+      element.augmentedInternal = augmented;
+      augmented.superclassConstraints.addAll(element.superclassConstraints);
+      augmented.interfaces.addAll(element.interfaces);
+    }
   }
 
   NullabilitySuffix _nullability(AstNode node, bool hasQuestion) {

pkg/analyzer/test/src/summary/element_text.dart

@@ -40,6 +40,7 @@ String getLibraryText({
 
 class ElementTextConfiguration {
   bool Function(Object) filter;
+  bool withAugmentedWithoutAugmentation = false;
   bool withCodeRanges = false;
   bool withConstantInitializers = true;
   bool withConstructors = true;
@@ -200,17 +201,20 @@ class _ElementWriter {
 
     // No augmentation, not interesting.
     if (e.augmentation == null) {
-      return;
+      expect(e.augmented, TypeMatcher<NotAugmentedInstanceElementImpl>());
+      if (!configuration.withAugmentedWithoutAugmentation) {
+        return;
+      }
     }
 
     _sink.writelnWithIndent('augmented');
     _sink.withIndent(() {
       final augmented = e.augmented;
       switch (augmented) {
-        case AugmentedClassElementImpl():
+        case AugmentedClassElement():
           _elementPrinter.writeTypeList('mixins', augmented.mixins);
           _elementPrinter.writeTypeList('interfaces', augmented.interfaces);
-        case AugmentedMixinElementImpl():
+        case AugmentedMixinElement():
           _elementPrinter.writeTypeList(
             'superclassConstraints',
             augmented.superclassConstraints,

pkg/analyzer/test/src/summary/elements_test.dart

@@ -26,19 +26,43 @@ main() {
 
 mixin ClassAugmentationElementsMixin on ElementsBaseTest {
   test_augmentationTarget() async {
-    newFile('$testPackageLibPath/a.dart', r'''
+    newFile('$testPackageLibPath/a1.dart', r'''
 library augment 'test.dart';
-import augment 'b.dart';
+import augment 'a11.dart';
+import augment 'a12.dart';
 augment class A {}
 ''');
 
-    newFile('$testPackageLibPath/b.dart', r'''
-library augment 'a.dart';
+    newFile('$testPackageLibPath/a11.dart', r'''
+library augment 'a1.dart';
+augment class A {}
+''');
+
+    newFile('$testPackageLibPath/a12.dart', r'''
+library augment 'a1.dart';
+augment class A {}
+''');
+
+    newFile('$testPackageLibPath/a2.dart', r'''
+library augment 'test.dart';
+import augment 'a21.dart';
+import augment 'a22.dart';
+augment class A {}
+''');
+
+    newFile('$testPackageLibPath/a21.dart', r'''
+library augment 'a2.dart';
+augment class A {}
+''');
+
+    newFile('$testPackageLibPath/a22.dart', r'''
+library augment 'a2.dart';
 augment class A {}
 ''');
 
     var library = await buildLibrary(r'''
-import augment 'a.dart';
+import augment 'a1.dart';
+import augment 'a2.dart';
 class A {}
 ''');
 
@@ -46,25 +70,54 @@ class A {}
 library
   definingUnit
     classes
-      class A @31
-        augmentation: self::@augmentation::package:test/a.dart::@classAugmentation::A
+      class A @58
+        augmentation: self::@augmentation::package:test/a1.dart::@classAugmentation::A
         constructors
           synthetic @-1
         augmented
   augmentationImports
-    package:test/a.dart
+    package:test/a1.dart
       definingUnit
         classAugmentations
-          augment class A @68
+          augment class A @97
             augmentationTarget: self::@class::A
             augmentedDeclaration: self::@class::A
-            augmentation: self::@augmentation::package:test/b.dart::@classAugmentation::A
+            augmentation: self::@augmentation::package:test/a11.dart::@classAugmentation::A
       augmentationImports
-        package:test/b.dart
+        package:test/a11.dart
           definingUnit
             classAugmentations
-              augment class A @40
-                augmentationTarget: self::@augmentation::package:test/a.dart::@classAugmentation::A
+              augment class A @41
+                augmentationTarget: self::@augmentation::package:test/a1.dart::@classAugmentation::A
+                augmentedDeclaration: self::@class::A
+                augmentation: self::@augmentation::package:test/a12.dart::@classAugmentation::A
+        package:test/a12.dart
+          definingUnit
+            classAugmentations
+              augment class A @41
+                augmentationTarget: self::@augmentation::package:test/a11.dart::@classAugmentation::A
+                augmentedDeclaration: self::@class::A
+                augmentation: self::@augmentation::package:test/a2.dart::@classAugmentation::A
+    package:test/a2.dart
+      definingUnit
+        classAugmentations
+          augment class A @97
+            augmentationTarget: self::@augmentation::package:test/a12.dart::@classAugmentation::A
+            augmentedDeclaration: self::@class::A
+            augmentation: self::@augmentation::package:test/a21.dart::@classAugmentation::A
+      augmentationImports
+        package:test/a21.dart
+          definingUnit
+            classAugmentations
+              augment class A @41
+                augmentationTarget: self::@augmentation::package:test/a2.dart::@classAugmentation::A
+                augmentedDeclaration: self::@class::A
+                augmentation: self::@augmentation::package:test/a22.dart::@classAugmentation::A
+        package:test/a22.dart
+          definingUnit
+            classAugmentations
+              augment class A @41
+                augmentationTarget: self::@augmentation::package:test/a21.dart::@classAugmentation::A
                 augmentedDeclaration: self::@class::A
 ''');
   }
@@ -342,6 +395,61 @@ library
 ''');
   }
 
+  test_notAugmented_interfaces() async {
+    var library = await buildLibrary(r'''
+class A implements I {}
+class I {}
+''');
+
+    configuration.withAugmentedWithoutAugmentation = true;
+    checkElementText(library, r'''
+library
+  definingUnit
+    classes
+      class A @6
+        interfaces
+          I
+        constructors
+          synthetic @-1
+        augmented
+          interfaces
+            I
+      class I @30
+        constructors
+          synthetic @-1
+        augmented
+''');
+  }
+
+  test_notAugmented_mixins() async {
+    var library = await buildLibrary(r'''
+class A implements M {}
+mixin M {}
+''');
+
+    configuration.withAugmentedWithoutAugmentation = true;
+    checkElementText(library, r'''
+library
+  definingUnit
+    classes
+      class A @6
+        interfaces
+          M
+        constructors
+          synthetic @-1
+        augmented
+          interfaces
+            M
+    mixins
+      mixin M @30
+        superclassConstraints
+          Object
+        augmented
+          superclassConstraints
+            Object
+''');
+  }
+
   test_notSimplyBounded_self() async {
     newFile('$testPackageLibPath/a.dart', r'''
 library augment 'test.dart';
@@ -45341,6 +45449,60 @@ library
 ''');
   }
 
+  test_notAugmented_interfaces() async {
+    var library = await buildLibrary(r'''
+mixin A implements I {}
+class I {}
+''');
+
+    configuration.withAugmentedWithoutAugmentation = true;
+    checkElementText(library, r'''
+library
+  definingUnit
+    classes
+      class I @30
+        constructors
+          synthetic @-1
+        augmented
+    mixins
+      mixin A @6
+        superclassConstraints
+          Object
+        interfaces
+          I
+        augmented
+          superclassConstraints
+            Object
+          interfaces
+            I
+''');
+  }
+
+  test_notAugmented_superclassConstraints() async {
+    var library = await buildLibrary(r'''
+mixin A on B {}
+class B {}
+''');
+
+    configuration.withAugmentedWithoutAugmentation = true;
+    checkElementText(library, r'''
+library
+  definingUnit
+    classes
+      class B @22
+        constructors
+          synthetic @-1
+        augmented
+    mixins
+      mixin A @6
+        superclassConstraints
+          B
+        augmented
+          superclassConstraints
+            B
+''');
+  }
+
   test_notSimplyBounded_self() async {
     newFile('$testPackageLibPath/a.dart', r'''
 library augment 'test.dart';