Deprecate Declaration.declaredElement, use 'declaredElement2' instead.

This is necessary to separate `ClassElement`, `EnumElement`, and `MixinElement`. And, in the future, augmentations like `ClassAugmentationElement`, etc.

Change-Id: Iecd2f8707212e53ef56f0e101880c7bab9e5d057
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/254104
Commit-Queue: Konstantin Shcheglov <scheglov@google.com>
Reviewed-by: Brian Wilkerson <brianwilkerson@google.com>

pkg/analysis_server/lib/src/computer/computer_outline.dart

@@ -414,7 +414,7 @@ class DartUnitOutlineComputer {
 
   /// Returns `true` if the given [element] is not `null` and deprecated.
   static bool _isDeprecated(Declaration declaration) {
-    var element = declaration.declaredElement;
+    var element = declaration.declaredElement2;
     return element != null && element.hasDeprecated;
   }
 

pkg/analysis_server/lib/src/computer/computer_overrides.dart

@@ -68,7 +68,7 @@ class DartUnitOverridesComputer {
         if (classMember.isStatic) {
           continue;
         }
-        _addOverride(classMember.name2, classMember.declaredElement);
+        _addOverride(classMember.name2, classMember.declaredElement2);
       }
       if (classMember is FieldDeclaration) {
         if (classMember.isStatic) {
@@ -76,7 +76,7 @@ class DartUnitOverridesComputer {
         }
         List<VariableDeclaration> fields = classMember.fields.variables;
         for (var field in fields) {
-          _addOverride(field.name2, field.declaredElement);
+          _addOverride(field.name2, field.declaredElement2);
         }
       }
     }

pkg/analysis_server/lib/src/domains/analysis/occurrences_dart.dart

@@ -28,7 +28,7 @@ class _DartUnitOccurrencesComputerVisitor extends RecursiveAstVisitor<void> {
 
   @override
   void visitEnumConstantDeclaration(EnumConstantDeclaration node) {
-    _addOccurrence(node.declaredElement!, node.name2.offset);
+    _addOccurrence(node.declaredElement2!, node.name2.offset);
 
     super.visitEnumConstantDeclaration(node);
   }

pkg/analysis_server/lib/src/services/completion/dart/enum_constant_constructor_contributor.dart

@@ -5,7 +5,6 @@
 import 'package:analysis_server/src/provisional/completion/dart/completion_dart.dart';
 import 'package:analyzer/dart/analysis/features.dart';
 import 'package:analyzer/dart/ast/ast.dart';
-import 'package:analyzer/dart/element/element.dart';
 
 /// A contributor that produces suggestions for constructors to be invoked
 /// in enum constants.
@@ -46,7 +45,7 @@ class EnumConstantConstructorContributor extends DartCompletionContributor {
       return;
     }
 
-    var enumElement = enumDeclaration.declaredElement as ClassElement;
+    var enumElement = enumDeclaration.declaredElement2!;
     for (var constructor in enumElement.constructors) {
       builder.suggestConstructor(
         constructor,

pkg/analysis_server/lib/src/services/completion/dart/feature_computer.dart

@@ -366,13 +366,13 @@ class FeatureComputer {
             : (node as ForElement).forLoopParts;
         if (loopParts is ForPartsWithDeclarations) {
           for (var declaredVariable in loopParts.variables.variables.reversed) {
-            if (declaredVariable.declaredElement == variable) {
+            if (declaredVariable.declaredElement2 == variable) {
               return distance;
             }
             distance++;
           }
         } else if (loopParts is ForEachPartsWithDeclaration) {
-          if (loopParts.loopVariable.declaredElement == variable) {
+          if (loopParts.loopVariable.declaredElement2 == variable) {
             return distance;
           }
           distance++;
@@ -384,7 +384,7 @@ class FeatureComputer {
           var index = variables.indexOf(node);
           for (var i = index - 1; i >= 0; i--) {
             var declaredVariable = variables[i];
-            if (declaredVariable.declaredElement == variable) {
+            if (declaredVariable.declaredElement2 == variable) {
               return distance;
             }
             distance++;
@@ -412,7 +412,7 @@ class FeatureComputer {
           if (statement is VariableDeclarationStatement) {
             for (var declaredVariable
                 in statement.variables.variables.reversed) {
-              if (declaredVariable.declaredElement == variable) {
+              if (declaredVariable.declaredElement2 == variable) {
                 return distance;
               }
               distance++;

pkg/analysis_server/lib/src/services/completion/dart/field_formal_contributor.dart

@@ -47,12 +47,12 @@ class FieldFormalContributor extends DartCompletionContributor {
       }
     }
 
-    ClassElement? enclosingClass;
+    InterfaceElement? enclosingClass;
     var constructorParent = constructor.parent;
     if (constructorParent is ClassDeclaration) {
-      enclosingClass = constructorParent.declaredElement;
+      enclosingClass = constructorParent.declaredElement2;
     } else if (constructorParent is EnumDeclaration) {
-      enclosingClass = constructorParent.declaredElement;
+      enclosingClass = constructorParent.declaredElement2;
     } else {
       return;
     }

pkg/analysis_server/lib/src/services/completion/dart/local_library_contributor.dart

@@ -47,7 +47,7 @@ class LibraryElementSuggestionBuilder extends GeneralizingElementVisitor {
   @override
   void visitClassElement(ClassElement element) {
     if (opType.includeTypeNameSuggestions) {
-      builder.suggestClass(element, prefix: prefix);
+      builder.suggestInterface(element, prefix: prefix);
     }
     if (opType.includeConstructorSuggestions) {
       _addConstructorSuggestions(element);

pkg/analysis_server/lib/src/services/completion/dart/local_reference_contributor.dart

@@ -85,9 +85,9 @@ class LocalReferenceContributor extends DartCompletionContributor {
       if (member != null) {
         var enclosingNode = member.parent;
         if (enclosingNode is ClassDeclaration) {
-          _addForInterface(enclosingNode.declaredElement!);
+          _addForInterface(enclosingNode.declaredElement2!);
         } else if (enclosingNode is MixinDeclaration) {
-          _addForInterface(enclosingNode.declaredElement!);
+          _addForInterface(enclosingNode.declaredElement2!);
         }
       }
     }
@@ -217,14 +217,14 @@ class _LocalVisitor extends LocalDeclarationVisitor {
 
   @override
   void declaredClass(ClassDeclaration declaration) {
-    _declaredClassElement(declaration.declaredElement);
+    _declaredInterfaceElement(declaration.declaredElement2);
   }
 
   @override
   void declaredClassTypeAlias(ClassTypeAlias declaration) {
-    var declaredElement = declaration.declaredElement;
+    var declaredElement = declaration.declaredElement2;
     if (declaredElement != null && opType.includeTypeNameSuggestions) {
-      builder.suggestClass(declaredElement);
+      builder.suggestInterface(declaredElement);
     }
   }
 
@@ -235,12 +235,12 @@ class _LocalVisitor extends LocalDeclarationVisitor {
 
   @override
   void declaredEnum(EnumDeclaration declaration) {
-    _declaredClassElement(declaration.declaredElement);
+    _declaredInterfaceElement(declaration.declaredElement2);
   }
 
   @override
   void declaredExtension(ExtensionDeclaration declaration) {
-    var declaredElement = declaration.declaredElement;
+    var declaredElement = declaration.declaredElement2;
     if (declaredElement != null &&
         visibilityTracker._isVisible(declaredElement) &&
         opType.includeReturnValueSuggestions &&
@@ -251,7 +251,7 @@ class _LocalVisitor extends LocalDeclarationVisitor {
 
   @override
   void declaredField(FieldDeclaration fieldDecl, VariableDeclaration varDecl) {
-    var field = varDecl.declaredElement;
+    var field = varDecl.declaredElement2;
     if (field is FieldElement &&
         ((visibilityTracker._isVisible(field) &&
                 opType.includeReturnValueSuggestions &&
@@ -260,7 +260,7 @@ class _LocalVisitor extends LocalDeclarationVisitor {
       var inheritanceDistance = 0.0;
       var enclosingClass = request.target.containingNode
           .thisOrAncestorOfType<ClassDeclaration>();
-      var enclosingElement = enclosingClass?.declaredElement;
+      var enclosingElement = enclosingClass?.declaredElement2;
       if (enclosingElement != null) {
         var enclosingElement = field.enclosingElement3;
         if (enclosingElement is ClassElement) {
@@ -274,7 +274,7 @@ class _LocalVisitor extends LocalDeclarationVisitor {
 
   @override
   void declaredFunction(FunctionDeclaration declaration) {
-    if (visibilityTracker._isVisible(declaration.declaredElement) &&
+    if (visibilityTracker._isVisible(declaration.declaredElement2) &&
         (opType.includeReturnValueSuggestions ||
             opType.includeVoidReturnSuggestions)) {
       if (declaration.isSetter) {
@@ -287,7 +287,7 @@ class _LocalVisitor extends LocalDeclarationVisitor {
           return;
         }
       }
-      var declaredElement = declaration.declaredElement;
+      var declaredElement = declaration.declaredElement2;
       if (declaredElement is FunctionElement) {
         builder.suggestTopLevelFunction(declaredElement, kind: _defaultKind);
       } else if (declaredElement is PropertyAccessorElement) {
@@ -298,7 +298,7 @@ class _LocalVisitor extends LocalDeclarationVisitor {
 
   @override
   void declaredFunctionTypeAlias(FunctionTypeAlias declaration) {
-    var declaredElement = declaration.declaredElement;
+    var declaredElement = declaration.declaredElement2;
     if (declaredElement != null && opType.includeTypeNameSuggestions) {
       builder.suggestTypeAlias(declaredElement);
     }
@@ -306,7 +306,7 @@ class _LocalVisitor extends LocalDeclarationVisitor {
 
   @override
   void declaredGenericTypeAlias(GenericTypeAlias declaration) {
-    var declaredElement = declaration.declaredElement;
+    var declaredElement = declaration.declaredElement2;
     if (declaredElement is TypeAliasElement &&
         opType.includeTypeNameSuggestions) {
       builder.suggestTypeAlias(declaredElement);
@@ -332,7 +332,7 @@ class _LocalVisitor extends LocalDeclarationVisitor {
 
   @override
   void declaredMethod(MethodDeclaration declaration) {
-    var element = declaration.declaredElement;
+    var element = declaration.declaredElement2;
     if (visibilityTracker._isVisible(element) &&
         (opType.includeReturnValueSuggestions ||
             opType.includeVoidReturnSuggestions) &&
@@ -345,7 +345,7 @@ class _LocalVisitor extends LocalDeclarationVisitor {
         if (enclosingElement is ClassElement) {
           inheritanceDistance = request.featureComputer
               .inheritanceDistanceFeature(
-                  enclosingClass.declaredElement!, enclosingElement);
+                  enclosingClass.declaredElement2!, enclosingElement);
         }
       }
       if (element is MethodElement) {
@@ -360,12 +360,12 @@ class _LocalVisitor extends LocalDeclarationVisitor {
 
   @override
   void declaredMixin(MixinDeclaration declaration) {
-    var declaredElement = declaration.declaredElement;
+    var declaredElement = declaration.declaredElement2;
     if (!inExtendsClause &&
         declaredElement != null &&
         visibilityTracker._isVisible(declaredElement) &&
         opType.includeTypeNameSuggestions) {
-      builder.suggestClass(declaredElement);
+      builder.suggestInterface(declaredElement);
     }
   }
 
@@ -387,7 +387,7 @@ class _LocalVisitor extends LocalDeclarationVisitor {
   @override
   void declaredTopLevelVar(
       VariableDeclarationList varList, VariableDeclaration varDecl) {
-    var variableElement = varDecl.declaredElement;
+    var variableElement = varDecl.declaredElement2;
     if (variableElement is TopLevelVariableElement &&
         visibilityTracker._isVisible(variableElement) &&
         opType.includeReturnValueSuggestions) {
@@ -400,7 +400,7 @@ class _LocalVisitor extends LocalDeclarationVisitor {
 
   @override
   void declaredTypeParameter(TypeParameter node) {
-    var declaredElement = node.declaredElement;
+    var declaredElement = node.declaredElement2;
     if (declaredElement != null &&
         visibilityTracker._isVisible(declaredElement) &&
         opType.includeTypeNameSuggestions) {
@@ -414,17 +414,19 @@ class _LocalVisitor extends LocalDeclarationVisitor {
     super.visitExtendsClause(node);
   }
 
-  void _declaredClassElement(ClassElement? class_) {
-    if (class_ != null && visibilityTracker._isVisible(class_)) {
+  void _declaredInterfaceElement(InterfaceElement? element) {
+    if (element != null && visibilityTracker._isVisible(element)) {
       if (opType.includeTypeNameSuggestions) {
-        builder.suggestClass(class_);
+        builder.suggestInterface(element);
       }
 
       if (!opType.isPrefixed &&
           opType.includeConstructorSuggestions &&
-          class_ is! EnumElement) {
-        for (final constructor in class_.constructors) {
-          if (!class_.isAbstract || constructor.isFactory) {
+          element is ClassElement &&
+          // TODO(scheglov) Remove when separated EnumElement from ClassElement
+          element is! EnumElement) {
+        for (final constructor in element.constructors) {
+          if (!element.isAbstract || constructor.isFactory) {
             builder.suggestConstructor(constructor);
           }
         }
@@ -435,7 +437,7 @@ class _LocalVisitor extends LocalDeclarationVisitor {
         final contextType = request.contextType;
         if (contextType is InterfaceType) {
           // TODO(scheglov) This looks not ideal - we should suggest getters.
-          for (final field in class_.fields) {
+          for (final field in element.fields) {
             if (field.isStatic &&
                 typeSystem.isSubtypeOf(field.type, contextType)) {
               builder.suggestStaticField(field);

pkg/analysis_server/lib/src/services/completion/dart/redirecting_contributor.dart

@@ -23,7 +23,7 @@ class RedirectingContributor extends DartCompletionContributor {
         // C() : this.^
         var containingConstructor =
             parent.thisOrAncestorOfType<ConstructorDeclaration>();
-        var constructorElement = containingConstructor?.declaredElement;
+        var constructorElement = containingConstructor?.declaredElement2;
         var classElement = constructorElement?.enclosingElement3;
         if (classElement != null) {
           for (var constructor in classElement.constructors) {
@@ -51,7 +51,7 @@ class RedirectingContributor extends DartCompletionContributor {
         // factory C() = ^
         var containingConstructor =
             parent.thisOrAncestorOfType<ConstructorDeclaration>();
-        var constructorElement = containingConstructor?.declaredElement;
+        var constructorElement = containingConstructor?.declaredElement2;
         var classElement = constructorElement?.enclosingElement3;
         var libraryElement = request.libraryElement;
         if (classElement == null) {

pkg/analysis_server/lib/src/services/completion/dart/suggestion_builder.dart

@@ -322,22 +322,6 @@ class SuggestionBuilder {
     );
   }
 
-  /// Add a suggestion for a [classElement]. If the class can only be
-  /// referenced using a prefix, then the [prefix] should be provided.
-  void suggestClass(ClassElement classElement, {String? prefix}) {
-    var relevance = _computeTopLevelRelevance(classElement,
-        elementType: _instantiateInterfaceElement(classElement));
-    _addBuilder(
-      _createCompletionSuggestionBuilder(
-        classElement,
-        kind: CompletionSuggestionKind.IDENTIFIER,
-        prefix: prefix,
-        relevance: relevance,
-        isNotImported: isNotImportedLibrary,
-      ),
-    );
-  }
-
   /// Add a suggestion to insert a closure matching the given function [type].
   /// If [includeTrailingComma] is `true` then the completion text will include
   /// a trailing comma, such as when the closure is part of an argument list.
@@ -452,7 +436,7 @@ class SuggestionBuilder {
   void suggestElement(Element element,
       {CompletionSuggestionKind kind = CompletionSuggestionKind.INVOCATION}) {
     if (element is ClassElement) {
-      suggestClass(element);
+      suggestInterface(element);
     } else if (element is ConstructorElement) {
       suggestConstructor(element, kind: kind);
     } else if (element is ExtensionElement) {
@@ -588,6 +572,22 @@ class SuggestionBuilder {
     );
   }
 
+  /// Add a suggestion for a [element]. If the class can only be
+  /// referenced using a prefix, then the [prefix] should be provided.
+  void suggestInterface(InterfaceElement element, {String? prefix}) {
+    var relevance = _computeTopLevelRelevance(element,
+        elementType: _instantiateInterfaceElement(element));
+    _addBuilder(
+      _createCompletionSuggestionBuilder(
+        element,
+        kind: CompletionSuggestionKind.IDENTIFIER,
+        prefix: prefix,
+        relevance: relevance,
+        isNotImported: isNotImportedLibrary,
+      ),
+    );
+  }
+
   /// Add a suggestion for a [keyword]. The [offset] is the offset from the
   /// beginning of the keyword where the cursor will be left.
   void suggestKeyword(String keyword, {int? offset}) {

pkg/analysis_server/lib/src/services/completion/dart/super_formal_contributor.dart

@@ -27,7 +27,7 @@ class SuperFormalContributor extends DartCompletionContributor {
       return;
     }
 
-    var constructorElement = constructor.declaredElement;
+    var constructorElement = constructor.declaredElement2;
     constructorElement as ConstructorElementImpl;
 
     var superConstructor = constructorElement.superConstructor;

pkg/analysis_server/lib/src/services/correction/dart/abstract_producer.dart

@@ -117,7 +117,7 @@ abstract class CorrectionProducer extends SingleCorrectionProducer {
     if (parent is VariableDeclaration) {
       var variableDeclaration = parent;
       if (variableDeclaration.initializer == expression) {
-        var variableElement = variableDeclaration.declaredElement;
+        var variableElement = variableDeclaration.declaredElement2;
         if (variableElement != null) {
           return variableElement.type;
         }

pkg/analysis_server/lib/src/services/correction/dart/add_async.dart

@@ -41,10 +41,10 @@ class AddAsync extends CorrectionProducer {
       DartType? returnType;
       if (parent is FunctionDeclaration) {
         body = parent.functionExpression.body;
-        returnType = parent.declaredElement!.returnType;
+        returnType = parent.declaredElement2!.returnType;
       } else if (parent is MethodDeclaration) {
         body = parent.body;
-        returnType = parent.declaredElement!.returnType;
+        returnType = parent.declaredElement2!.returnType;
       }
       if (body == null || returnType == null) {
         return;

pkg/analysis_server/lib/src/services/correction/dart/add_call_super.dart

@@ -36,7 +36,7 @@ class AddCallSuper extends CorrectionProducer {
     if (methodDeclaration == null) return;
     var classElement = methodDeclaration
         .thisOrAncestorOfType<ClassDeclaration>()
-        ?.declaredElement;
+        ?.declaredElement2;
     if (classElement == null) return;
 
     var name = Name(classElement.library.source.uri, node.name);

pkg/analysis_server/lib/src/services/correction/dart/add_diagnostic_property_reference.dart

@@ -40,7 +40,8 @@ class AddDiagnosticPropertyReference extends CorrectionProducer {
 
     final classDeclaration = node.thisOrAncestorOfType<ClassDeclaration>();
     if (classDeclaration == null ||
-        !flutter.isDiagnosticable(classDeclaration.declaredElement!.thisType)) {
+        !flutter
+            .isDiagnosticable(classDeclaration.declaredElement2!.thisType)) {
       return;
     }
 
@@ -194,13 +195,13 @@ class AddDiagnosticPropertyReference extends CorrectionProducer {
   DartType? _getReturnType(AstNode node) {
     if (node is MethodDeclaration) {
       // Getter.
-      var element = node.declaredElement;
+      var element = node.declaredElement2;
       if (element is PropertyAccessorElement) {
         return element.returnType;
       }
     } else if (node is VariableDeclaration) {
       // Field.
-      var element = node.declaredElement;
+      var element = node.declaredElement2;
       if (element is FieldElement) {
         return element.type;
       }

pkg/analysis_server/lib/src/services/correction/dart/add_explicit_cast.dart

@@ -38,7 +38,7 @@ class AddExplicitCast extends CorrectionProducer {
     if (parent is AssignmentExpression && target == parent.rightHandSide) {
       toType = parent.writeType!;
     } else if (parent is VariableDeclaration && target == parent.initializer) {
-      toType = parent.declaredElement!.type;
+      toType = parent.declaredElement2!.type;
     } else {
       // TODO(brianwilkerson) Handle function arguments.
       return;

pkg/analysis_server/lib/src/services/correction/dart/add_field_formal_parameters.dart

@@ -28,7 +28,7 @@ class AddFieldFormalParameters extends CorrectionProducer {
       return;
     }
 
-    var superType = classNode.declaredElement!.supertype;
+    var superType = classNode.declaredElement2!.supertype;
     if (superType == null) {
       return;
     }

pkg/analysis_server/lib/src/services/correction/dart/add_key_to_constructors.dart

@@ -36,7 +36,7 @@ class AddKeyToConstructors extends CorrectionProducer {
         return;
       }
       var className = node.name;
-      var constructors = parent.declaredElement?.supertype?.constructors;
+      var constructors = parent.declaredElement2?.supertype?.constructors;
       if (constructors == null) {
         return;
       }

pkg/analysis_server/lib/src/services/correction/dart/add_null_check.dart

@@ -74,14 +74,14 @@ class AddNullCheck extends CorrectionProducer {
     if (parent is AssignmentExpression && target == parent.rightHandSide) {
       toType = parent.writeType;
     } else if (parent is VariableDeclaration && target == parent.initializer) {
-      toType = parent.declaredElement?.type;
+      toType = parent.declaredElement2?.type;
     } else if (parent is ArgumentList) {
       toType = target.staticParameterElement?.type;
     } else if (parent is IndexExpression) {
       toType = parent.realTarget.typeOrThrow;
     } else if (parent is ForEachPartsWithDeclaration) {
       toType =
-          typeProvider.iterableType(parent.loopVariable.declaredElement!.type);
+          typeProvider.iterableType(parent.loopVariable.declaredElement2!.type);
     } else if (parent is ForEachPartsWithIdentifier) {
       toType = typeProvider.iterableType(parent.identifier.typeOrThrow);
     } else if (parent is SpreadElement) {

pkg/analysis_server/lib/src/services/correction/dart/add_super_constructor_invocation.dart

@@ -24,7 +24,7 @@ class AddSuperConstructorInvocation extends MultiCorrectionProducer {
       return;
     }
 
-    var targetClassElement = targetClassNode.declaredElement!;
+    var targetClassElement = targetClassNode.declaredElement2!;
     var superType = targetClassElement.supertype;
     if (superType == null) {
       return;

pkg/analysis_server/lib/src/services/correction/dart/add_type_annotation.dart

@@ -104,7 +104,7 @@ class AddTypeAnnotation extends CorrectionProducer {
       var targetClassDeclaration =
           target.thisOrAncestorOfType<ClassDeclaration>();
       if (targetClassDeclaration != null) {
-        utils.targetClassElement = targetClassDeclaration.declaredElement;
+        utils.targetClassElement = targetClassDeclaration.declaredElement2;
       }
     }
   }
@@ -115,7 +115,7 @@ class AddTypeAnnotation extends CorrectionProducer {
     if (declaredIdentifier.type != null) {
       return;
     }
-    var type = declaredIdentifier.declaredElement!.type;
+    var type = declaredIdentifier.declaredElement2!.type;
     if (type is! InterfaceType && type is! FunctionType) {
       return;
     }
@@ -183,7 +183,7 @@ class AddTypeAnnotation extends CorrectionProducer {
     if (statement is! VariableDeclarationStatement || block is! Block) {
       return null;
     }
-    var element = variable.declaredElement;
+    var element = variable.declaredElement2;
     if (element is! LocalVariableElement) {
       return null;
     }

pkg/analysis_server/lib/src/services/correction/dart/change_to.dart

@@ -141,7 +141,7 @@ class ChangeTo extends CorrectionProducer {
     if (target == null) {
       var clazz = this.node.thisOrAncestorOfType<ClassDeclaration>();
       if (clazz != null) {
-        var classElement = clazz.declaredElement!;
+        var classElement = clazz.declaredElement2!;
         _updateFinderWithClassMembers(finder, classElement);
       }
     } else if (target is ExtensionOverride) {
@@ -292,7 +292,7 @@ class ChangeTo extends CorrectionProducer {
       var targetClassNode = parent.thisOrAncestorOfType<ClassDeclaration>();
       if (targetClassNode == null) return;
 
-      var targetClassElement = targetClassNode.declaredElement!;
+      var targetClassElement = targetClassNode.declaredElement2!;
       var superType = targetClassElement.supertype;
       if (superType == null) return;
 

pkg/analysis_server/lib/src/services/correction/dart/convert_class_to_enum.dart

@@ -347,7 +347,7 @@ class _EnumDescription {
   /// description of the conversion work to be done. Otherwise, return `null`.
   static _EnumDescription? fromClass(ClassDeclaration node) {
     // The class must be a concrete class.
-    var classElement = node.declaredElement;
+    var classElement = node.declaredElement2;
     if (classElement == null || classElement.isAbstract) {
       return null;
     }
@@ -516,7 +516,7 @@ class _EnumDescription {
     var constructors = _Constructors();
     for (var member in classDeclaration.members) {
       if (member is ConstructorDeclaration) {
-        var constructor = member.declaredElement;
+        var constructor = member.declaredElement2;
         if (constructor is ConstructorElement) {
           if (!classElement.isPrivate && !constructor.isPrivate) {
             // Public constructor in public enum.
@@ -550,7 +550,7 @@ class _EnumDescription {
         var fields = fieldList.variables;
         if (member.isStatic) {
           for (var field in fields) {
-            var fieldElement = field.declaredElement;
+            var fieldElement = field.declaredElement2;
             if (fieldElement is FieldElement) {
               var fieldType = fieldElement.type;
               // The field can be converted to be an enum constant if it
@@ -597,7 +597,7 @@ class _EnumDescription {
               // Non-final instance field.
               return null;
             }
-            var fieldElement = field.declaredElement;
+            var fieldElement = field.declaredElement2;
             if (fieldElement is FieldElement) {
               var fieldType = fieldElement.type;
               if (fieldElement.name == 'index' && fieldType.isDartCoreInt) {
@@ -723,7 +723,7 @@ class _NonEnumVisitor extends _BaseVisitor {
 
   @override
   void visitClassDeclaration(ClassDeclaration node) {
-    var element = node.declaredElement;
+    var element = node.declaredElement2;
     if (element == null) {
       throw _CannotConvertException('Unresolved');
     }

pkg/analysis_server/lib/src/services/correction/dart/convert_class_to_mixin.dart

@@ -36,7 +36,7 @@ class ConvertClassToMixin extends CorrectionProducer {
     var superclassConstraints = <InterfaceType>[];
     var interfaces = <InterfaceType>[];
 
-    var classElement = classDeclaration.declaredElement!;
+    var classElement = classDeclaration.declaredElement2!;
     for (var type in classElement.mixins) {
       if (referencedClasses.contains(type.element2)) {
         superclassConstraints.add(type);

pkg/analysis_server/lib/src/services/correction/dart/convert_into_block_body.dart

@@ -96,9 +96,9 @@ class ConvertIntoBlockBody extends CorrectionProducer {
 
   ExecutableElement? _getFunctionElement(AstNode? node) {
     if (node is MethodDeclaration) {
-      return node.declaredElement;
+      return node.declaredElement2;
     } else if (node is ConstructorDeclaration) {
-      return node.declaredElement;
+      return node.declaredElement2;
     } else if (node is FunctionExpression) {
       return node.declaredElement;
     }

pkg/analysis_server/lib/src/services/correction/dart/convert_into_final_field.dart

@@ -42,7 +42,7 @@ class ConvertIntoFinalField extends CorrectionProducer {
 
     // Check that there is no corresponding setter.
     {
-      var element = getter.declaredElement;
+      var element = getter.declaredElement2;
       if (element == null) {
         return;
       }

pkg/analysis_server/lib/src/services/correction/dart/create_constructor.dart

@@ -109,7 +109,7 @@ class CreateConstructor extends CorrectionProducer {
     if (grandParent is! EnumDeclaration) {
       return;
     }
-    var targetElement = grandParent.declaredElement;
+    var targetElement = grandParent.declaredElement2;
     if (targetElement == null) {
       return;
     }

pkg/analysis_server/lib/src/services/correction/dart/create_constructor_for_final_fields.dart

@@ -29,7 +29,7 @@ class CreateConstructorForFinalFields extends CorrectionProducer {
     }
 
     var className = classDeclaration.name2.lexeme;
-    var superType = classDeclaration.declaredElement?.supertype;
+    var superType = classDeclaration.declaredElement2?.supertype;
     if (superType == null) {
       return;
     }

pkg/analysis_server/lib/src/services/correction/dart/create_constructor_super.dart

@@ -19,7 +19,7 @@ class CreateConstructorSuper extends MultiCorrectionProducer {
       return;
     }
 
-    var targetClassElement = targetClassNode.declaredElement!;
+    var targetClassElement = targetClassNode.declaredElement2!;
     var superType = targetClassElement.supertype;
     if (superType == null) {
       return;

pkg/analysis_server/lib/src/services/correction/dart/create_method.dart

@@ -65,7 +65,7 @@ class CreateMethod extends CorrectionProducer {
     }
     final classDecl = memberDecl.thisOrAncestorOfType<ClassDeclaration>();
     if (classDecl != null) {
-      final classElement = classDecl.declaredElement!;
+      final classElement = classDecl.declaredElement2!;
 
       var missingEquals = memberDecl is FieldDeclaration ||
           (memberDecl as MethodDeclaration).name2.lexeme == 'hashCode';

pkg/analysis_server/lib/src/services/correction/dart/create_missing_overrides.dart

@@ -28,7 +28,7 @@ class CreateMissingOverrides extends CorrectionProducer {
       return;
     }
     var targetClass = node.parent as ClassDeclaration;
-    utils.targetClassElement = targetClass.declaredElement;
+    utils.targetClassElement = targetClass.declaredElement2;
     var signatures =
         InheritanceOverrideVerifier.missingOverrides(targetClass).toList();
     // sort by name, getters before setters

pkg/analysis_server/lib/src/services/correction/dart/encapsulate_field.dart

@@ -41,7 +41,7 @@ class EncapsulateField extends CorrectionProducer {
     }
     var field = fields.first;
     var nameToken = field.name2;
-    var fieldElement = field.declaredElement as FieldElement;
+    var fieldElement = field.declaredElement2 as FieldElement;
     // should have a public name
     var name = nameToken.lexeme;
     if (Identifier.isPrivateName(name)) {

pkg/analysis_server/lib/src/services/correction/dart/flutter_convert_to_stateful_widget.dart

@@ -35,7 +35,7 @@ class FlutterConvertToStatefulWidget extends CorrectionProducer {
     }
 
     // Must be a StatelessWidget subclass.
-    var widgetClassElement = widgetClass.declaredElement!;
+    var widgetClassElement = widgetClass.declaredElement2!;
     var superType = widgetClassElement.supertype;
     if (superType == null || !flutter.isExactlyStatelessWidgetType(superType)) {
       return;
@@ -66,7 +66,7 @@ class FlutterConvertToStatefulWidget extends CorrectionProducer {
     for (var member in widgetClass.members) {
       if (member is FieldDeclaration && !member.isStatic) {
         for (var fieldNode in member.fields.variables) {
-          var fieldElement = fieldNode.declaredElement as FieldElement;
+          var fieldElement = fieldNode.declaredElement2 as FieldElement;
           if (!fieldsAssignedInConstructors.contains(fieldElement)) {
             nodesToMove.add(member);
             elementsToMove.add(fieldElement);
@@ -84,7 +84,7 @@ class FlutterConvertToStatefulWidget extends CorrectionProducer {
         }
       } else if (member is MethodDeclaration && !member.isStatic) {
         nodesToMove.add(member);
-        elementsToMove.add(member.declaredElement!);
+        elementsToMove.add(member.declaredElement2!);
       }
     }
 

pkg/analysis_server/lib/src/services/correction/dart/flutter_convert_to_stateless_widget.dart

@@ -36,7 +36,7 @@ class FlutterConvertToStatelessWidget extends CorrectionProducer {
     }
 
     // Must be a StatefulWidget subclass.
-    var widgetClassElement = widgetClass.declaredElement!;
+    var widgetClassElement = widgetClass.declaredElement2!;
     var superType = widgetClassElement.supertype;
     if (superType == null || !flutter.isExactlyStatefulWidgetType(superType)) {
       return;
@@ -46,7 +46,7 @@ class FlutterConvertToStatelessWidget extends CorrectionProducer {
     if (createStateMethod == null) return;
 
     var stateClass = _findStateClass(widgetClassElement);
-    var stateClassElement = stateClass?.declaredElement;
+    var stateClassElement = stateClass?.declaredElement2;
     if (stateClass == null ||
         stateClassElement == null ||
         !Identifier.isPrivateName(stateClass.name2.lexeme) ||
@@ -84,7 +84,7 @@ class FlutterConvertToStatelessWidget extends CorrectionProducer {
           return;
         }
         for (var fieldNode in member.fields.variables) {
-          var fieldElement = fieldNode.declaredElement as FieldElement;
+          var fieldElement = fieldNode.declaredElement2 as FieldElement;
           if (!fieldsAssignedInConstructors.contains(fieldElement)) {
             nodesToMove.add(member);
             elementsToMove.add(fieldElement);
@@ -106,7 +106,7 @@ class FlutterConvertToStatelessWidget extends CorrectionProducer {
         }
         if (!_isDefaultOverride(member)) {
           nodesToMove.add(member);
-          elementsToMove.add(member.declaredElement!);
+          elementsToMove.add(member.declaredElement2!);
         }
       }
     }
@@ -391,7 +391,7 @@ class _StateUsageVisitor extends RecursiveAstVisitor<void> {
         methodDeclaration?.thisOrAncestorOfType<ClassDeclaration>();
 
     if (methodDeclaration?.name2.lexeme != 'createState' ||
-        classDeclaration?.declaredElement != widgetClassElement) {
+        classDeclaration?.declaredElement2 != widgetClassElement) {
       used = true;
     }
   }

pkg/analysis_server/lib/src/services/correction/dart/import_library.dart

@@ -356,11 +356,11 @@ class ImportLibrary extends MultiCorrectionProducer {
     DartType? enclosingThisType(AstNode node) {
       var parent = node.parent;
       if (parent is ClassDeclaration) {
-        return parent.declaredElement?.thisType;
+        return parent.declaredElement2?.thisType;
       } else if (parent is ExtensionDeclaration) {
         return parent.extendedType.type;
       } else if (parent is MixinDeclaration) {
-        return parent.declaredElement?.thisType;
+        return parent.declaredElement2?.thisType;
       } else {
         return null;
       }

pkg/analysis_server/lib/src/services/correction/dart/join_variable_declaration.dart

@@ -75,7 +75,7 @@ class JoinVariableDeclaration extends CorrectionProducer {
     // The declared variable must be the one that is assigned.
     // There must be no initializer.
     var declaredVariable = declaredVariables.single;
-    if (declaredVariable.declaredElement != left.staticElement ||
+    if (declaredVariable.declaredElement2 != left.staticElement ||
         declaredVariable.initializer != null) {
       return;
     }
@@ -137,7 +137,7 @@ class JoinVariableDeclaration extends CorrectionProducer {
     }
 
     // The assignment should write into the declared variable.
-    if (assignment.writeElement != declaredVariable.declaredElement) {
+    if (assignment.writeElement != declaredVariable.declaredElement2) {
       return;
     }
 

pkg/analysis_server/lib/src/services/correction/dart/make_variable_nullable.dart

@@ -63,7 +63,7 @@ class MakeVariableNullable extends CorrectionProducer {
         if (statement is VariableDeclarationStatement) {
           var variableList = statement.variables;
           for (var declaration in variableList.variables) {
-            if (declaration.declaredElement == variable) {
+            if (declaration.declaredElement2 == variable) {
               return variableList;
             }
           }
@@ -201,7 +201,7 @@ class MakeVariableNullable extends CorrectionProducer {
       return;
     }
 
-    var oldType = parent.declaredElement!.type;
+    var oldType = parent.declaredElement2!.type;
     if (oldType is! InterfaceTypeImpl) {
       return;
     }

pkg/analysis_server/lib/src/services/correction/dart/remove_abstract.dart

@@ -59,7 +59,7 @@ class RemoveAbstract extends CorrectionProducerWithDiagnostic {
           continue;
         }
         for (var variable in variables) {
-          if (variable.declaredElement == node.staticElement) {
+          if (variable.declaredElement2 == node.staticElement) {
             var abstractKeyword = member.abstractKeyword;
             if (abstractKeyword != null) {
               await builder.addDartFileEdit(file, (builder) {

pkg/analysis_server/lib/src/services/correction/dart/remove_unused.dart

@@ -42,8 +42,8 @@ class RemoveUnusedElement extends _RemoveUnused {
         referencedNode is MethodDeclaration ||
         referencedNode is VariableDeclaration) {
       final element = referencedNode is Declaration
-          ? referencedNode.declaredElement!
-          : (referencedNode as NamedCompilationUnitMember).declaredElement!;
+          ? referencedNode.declaredElement2!
+          : (referencedNode as NamedCompilationUnitMember).declaredElement2!;
       final references = _findAllReferences(unit, element);
       // todo (pq): consider filtering for references that are limited to within the class.
       if (references.length == 1) {
@@ -92,7 +92,7 @@ class RemoveUnusedField extends _RemoveUnused {
       return;
     }
 
-    final element = declaration.declaredElement;
+    final element = declaration.declaredElement2;
     if (element is! FieldElement) {
       return;
     }

pkg/analysis_server/lib/src/services/correction/dart/remove_unused_local_variable.dart

@@ -31,7 +31,7 @@ class RemoveUnusedLocalVariable extends CorrectionProducer {
       return;
     }
 
-    var element = declaration.declaredElement;
+    var element = declaration.declaredElement2;
     if (element is! LocalVariableElement) {
       return;
     }

pkg/analysis_server/lib/src/services/correction/dart/rename_method_parameter.dart

@@ -34,7 +34,7 @@ class RenameMethodParameter extends CorrectionProducer {
     if (methodParameters == null) return;
 
     var classDeclaration = method.parent as Declaration;
-    var classElement = classDeclaration.declaredElement;
+    var classElement = classDeclaration.declaredElement2;
     if (classElement is! ClassElement) return;
 
     var parentMethod = classElement.lookUpInheritedMethod(

pkg/analysis_server/lib/src/services/correction/dart/replace_conditional_with_if_else.dart

@@ -107,7 +107,7 @@ class ReplaceConditionalWithIfElse extends CorrectionProducer {
           var variable = conditional.parent as VariableDeclaration;
           var variableList = variable.parent as VariableDeclarationList;
           if (variableList.type == null) {
-            var type = variable.declaredElement!.type;
+            var type = variable.declaredElement2!.type;
             var keyword = variableList.keyword;
             if (keyword != null && keyword.keyword == Keyword.VAR) {
               builder.addReplacement(range.token(keyword), (builder) {

pkg/analysis_server/lib/src/services/correction/dart/replace_return_type.dart

@@ -84,12 +84,12 @@ class ReplaceReturnType extends CorrectionProducer {
     if (newType != null) {
       var clazz = method.thisOrAncestorOfType<ClassDeclaration>();
       if (clazz != null) {
-        var classElement = clazz.declaredElement!;
+        var classElement = clazz.declaredElement2!;
         var overriddenList = InheritanceManager3().getOverridden2(
             classElement,
             Name(
               classElement.library.source.uri,
-              method.declaredElement!.name,
+              method.declaredElement2!.name,
             ));
 
         if (overriddenList != null) {

pkg/analysis_server/lib/src/services/correction/dart/split_variable_declaration.dart

@@ -52,7 +52,7 @@ class SplitVariableDeclaration extends CorrectionProducer {
 
     await builder.addDartFileEdit(file, (builder) {
       if (variableList.type == null) {
-        final type = variable.declaredElement!.type;
+        final type = variable.declaredElement2!.type;
         if (!type.isDynamic && keyword != null) {
           if (!builder.canWriteType(type)) {
             return;

pkg/analysis_server/lib/src/services/correction/dart/surround_with.dart

@@ -241,7 +241,7 @@ class _SurroundWithSetState extends _SurroundWith {
     var classDeclaration =
         node.parent?.thisOrAncestorOfType<ClassDeclaration>();
     if (classDeclaration != null &&
-        flutter.isState(classDeclaration.declaredElement)) {
+        flutter.isState(classDeclaration.declaredElement2)) {
       await builder.addDartFileEdit(file, (builder) {
         builder.addReplacement(statementsRange, (builder) {
           builder.write(indentOld);

pkg/analysis_server/lib/src/services/correction/fix/data_driven/rename_parameter.dart

@@ -120,7 +120,7 @@ extension on MethodDeclaration {
   /// Return the element that this method overrides, or `null` if this method
   /// doesn't override any inherited member.
   ExecutableElement? overriddenElement() {
-    var element = declaredElement;
+    var element = declaredElement2;
     if (element != null) {
       var enclosingElement = element.enclosingElement3;
       if (enclosingElement is ClassElement) {

pkg/analysis_server/lib/src/services/correction/util.dart

@@ -255,13 +255,13 @@ AstNode? getEnclosingClassOrUnitMember(AstNode input) {
 ExecutableElement? getEnclosingExecutableElement(AstNode input) {
   for (var node in input.withParents) {
     if (node is FunctionDeclaration) {
-      return node.declaredElement;
+      return node.declaredElement2;
     }
     if (node is ConstructorDeclaration) {
-      return node.declaredElement;
+      return node.declaredElement2;
     }
     if (node is MethodDeclaration) {
-      return node.declaredElement;
+      return node.declaredElement2;
     }
   }
   return null;

pkg/analysis_server/lib/src/services/kythe/kythe_visitors.dart

@@ -202,7 +202,7 @@ class KytheDartVisitor extends GeneralizingAstVisitor<void> with OutputUtils {
     if (refVName != null) {
       var parentNode = node.parent;
       if (parentNode is Declaration) {
-        var parentElement = parentNode.declaredElement;
+        var parentElement = parentNode.declaredElement2;
         if (parentNode is TopLevelVariableDeclaration) {
           _handleVariableDeclarationListAnnotations(
               parentNode.variables, refVName);
@@ -279,7 +279,7 @@ class KytheDartVisitor extends GeneralizingAstVisitor<void> with OutputUtils {
 
   @override
   void visitClassDeclaration(ClassDeclaration node) {
-    return _withEnclosingElement(node.declaredElement!, () {
+    return _withEnclosingElement(node.declaredElement2!, () {
       // record/ class node
       addNodeAndFacts(schema.RECORD_KIND,
           nodeVName: _enclosingClassVName,
@@ -346,7 +346,7 @@ class KytheDartVisitor extends GeneralizingAstVisitor<void> with OutputUtils {
 
   @override
   void visitClassTypeAlias(ClassTypeAlias node) {
-    return _withEnclosingElement(node.declaredElement!, () {
+    return _withEnclosingElement(node.declaredElement2!, () {
       // record/ class node
       addNodeAndFacts(schema.RECORD_KIND,
           nodeVName: _enclosingClassVName,
@@ -460,7 +460,7 @@ class KytheDartVisitor extends GeneralizingAstVisitor<void> with OutputUtils {
 
   @override
   void visitConstructorDeclaration(ConstructorDeclaration node) {
-    var declaredElement = node.declaredElement!;
+    var declaredElement = node.declaredElement2!;
     return _withEnclosingElement(declaredElement, () {
       // function/ constructor node
       var constructorVName = addNodeAndFacts(schema.FUNCTION_KIND,
@@ -502,7 +502,7 @@ class KytheDartVisitor extends GeneralizingAstVisitor<void> with OutputUtils {
 
   @override
   void visitDeclaredIdentifier(DeclaredIdentifier node) {
-    var declaredElement = node.declaredElement!;
+    var declaredElement = node.declaredElement2!;
     _handleVariableDeclaration(declaredElement, node.name,
         subKind: schema.LOCAL_SUBKIND, type: declaredElement.type);
 
@@ -513,7 +513,7 @@ class KytheDartVisitor extends GeneralizingAstVisitor<void> with OutputUtils {
   void visitEnumConstantDeclaration(EnumConstantDeclaration node) {
     // constant node
     var constDeclVName =
-        addNodeAndFacts(schema.CONSTANT_KIND, element: node.declaredElement);
+        addNodeAndFacts(schema.CONSTANT_KIND, element: node.declaredElement2);
 
     // anchor- defines/binding, defines
     addAnchorEdgesContainingEdge(
@@ -530,7 +530,7 @@ class KytheDartVisitor extends GeneralizingAstVisitor<void> with OutputUtils {
 
   @override
   void visitEnumDeclaration(EnumDeclaration node) {
-    return _withEnclosingElement(node.declaredElement!, () {
+    return _withEnclosingElement(node.declaredElement2!, () {
       // record/ enum node
       addNodeAndFacts(schema.RECORD_KIND,
           nodeVName: _enclosingClassVName,
@@ -591,7 +591,7 @@ class KytheDartVisitor extends GeneralizingAstVisitor<void> with OutputUtils {
 
   @override
   void visitFunctionDeclaration(FunctionDeclaration node) {
-    var declaredElement = node.declaredElement!;
+    var declaredElement = node.declaredElement2!;
     return _withEnclosingElement(declaredElement, () {
       // function node
       var functionVName = addNodeAndFacts(schema.FUNCTION_KIND,
@@ -743,7 +743,7 @@ class KytheDartVisitor extends GeneralizingAstVisitor<void> with OutputUtils {
 
   @override
   void visitMethodDeclaration(MethodDeclaration node) {
-    var declaredElement = node.declaredElement!;
+    var declaredElement = node.declaredElement2!;
     return _withEnclosingElement(declaredElement, () {
       // function node
       var methodVName = addNodeAndFacts(schema.FUNCTION_KIND,
@@ -918,7 +918,7 @@ class KytheDartVisitor extends GeneralizingAstVisitor<void> with OutputUtils {
         _enclosingVName != _enclosingFileVName;
 
     // variable
-    var declaredElement = node.declaredElement!;
+    var declaredElement = node.declaredElement2!;
     _handleVariableDeclaration(declaredElement, node.name2,
         subKind: isLocal ? schema.LOCAL_SUBKIND : schema.FIELD_SUBKIND,
         type: declaredElement.type);
@@ -1104,9 +1104,9 @@ class KytheDartVisitor extends GeneralizingAstVisitor<void> with OutputUtils {
   void _handleVariableDeclarationListAnnotations(
       VariableDeclarationList variableDeclarationList, KytheVName refVName) {
     for (var varDecl in variableDeclarationList.variables) {
-      if (varDecl.declaredElement != null) {
+      if (varDecl.declaredElement2 != null) {
         var parentVName =
-            _vNameFromElement(varDecl.declaredElement, schema.VARIABLE_KIND);
+            _vNameFromElement(varDecl.declaredElement2, schema.VARIABLE_KIND);
         addEdge(parentVName, schema.ANNOTATED_BY_EDGE, refVName);
       } else {
         // The element out of the VarDeclarationList is null

pkg/analysis_server/lib/src/services/refactoring/legacy/extract_method.dart

@@ -435,15 +435,15 @@ class ExtractMethodRefactoringImpl extends RefactoringImpl
       return validateCreateFunction(searchEngine, libraryElement, name);
     }
     // method of class
-    ClassElement? classElement;
+    InterfaceElement? interfaceElement;
     if (parent is ClassDeclaration) {
-      classElement = parent.declaredElement!;
+      interfaceElement = parent.declaredElement2!;
     } else if (parent is EnumDeclaration) {
-      classElement = parent.declaredElement!;
+      interfaceElement = parent.declaredElement2!;
     }
-    if (classElement != null) {
+    if (interfaceElement != null) {
       return validateCreateMethod(searchEngine,
-          AnalysisSessionHelper(resolveResult.session), classElement, name);
+          AnalysisSessionHelper(resolveResult.session), interfaceElement, name);
     }
     // OK
     return Future<RefactoringStatus>.value(result);

pkg/analysis_server/lib/src/services/refactoring/legacy/extract_widget.dart

@@ -184,7 +184,7 @@ class ExtractWidgetRefactoringImpl extends RefactoringImpl
 
     // Find the enclosing class.
     _enclosingClassNode = node?.thisOrAncestorOfType<ClassDeclaration>();
-    _enclosingClassElement = _enclosingClassNode?.declaredElement;
+    _enclosingClassElement = _enclosingClassNode?.declaredElement2;
 
     // new MyWidget(...)
     var newExpression = _flutter.identifyNewExpression(node);
@@ -372,7 +372,7 @@ class ExtractWidgetRefactoringImpl extends RefactoringImpl
   /// Replace invocations of the [_method] with instantiations of the new
   /// widget class.
   void _replaceInvocationsWithInstantiations(DartFileEditBuilder builder) {
-    var collector = _MethodInvocationsCollector(_method!.declaredElement!);
+    var collector = _MethodInvocationsCollector(_method!.declaredElement2!);
     _enclosingClassNode!.accept(collector);
     for (var invocation in collector.invocations) {
       List<Expression> arguments = invocation.argumentList.arguments;

pkg/analysis_server/lib/src/services/refactoring/legacy/rename_class_member.dart

@@ -22,15 +22,15 @@ import 'package:analyzer/src/dart/analysis/session_helper.dart';
 import 'package:analyzer/src/generated/java_core.dart';
 import 'package:analyzer/src/generated/source.dart';
 
-/// Checks if creating a method with the given [name] in [classElement] will
+/// Checks if creating a method with the given [name] in [interfaceElement] will
 /// cause any conflicts.
 Future<RefactoringStatus> validateCreateMethod(
     SearchEngine searchEngine,
     AnalysisSessionHelper sessionHelper,
-    ClassElement classElement,
+    InterfaceElement interfaceElement,
     String name) {
   return _CreateClassMemberValidator(
-          searchEngine, sessionHelper, classElement, name)
+          searchEngine, sessionHelper, interfaceElement, name)
       .validate();
 }
 
@@ -127,7 +127,7 @@ class RenameClassMemberRefactoringImpl extends RenameRefactoringImpl {
 class _BaseClassMemberValidator {
   final SearchEngine searchEngine;
   final AnalysisSessionHelper sessionHelper;
-  final ClassElement elementClass;
+  final InterfaceElement interfaceElement;
   final ElementKind elementKind;
   final String name;
 
@@ -136,21 +136,21 @@ class _BaseClassMemberValidator {
   _BaseClassMemberValidator(
     this.searchEngine,
     this.sessionHelper,
-    this.elementClass,
+    this.interfaceElement,
     this.elementKind,
     this.name,
   );
 
-  LibraryElement get library => elementClass.library;
+  LibraryElement get library => interfaceElement.library;
 
   void _checkClassAlreadyDeclares() {
     // check if there is a member with "newName" in the same ClassElement
-    for (var newNameMember in getChildren(elementClass, name)) {
+    for (var newNameMember in getChildren(interfaceElement, name)) {
       result.addError(
         format(
           "{0} '{1}' already declares {2} with name '{3}'.",
-          capitalize(elementClass.kind.displayName),
-          elementClass.displayName,
+          capitalize(interfaceElement.kind.displayName),
+          interfaceElement.displayName,
           getElementKindName(newNameMember),
           name,
         ),
@@ -164,7 +164,7 @@ class _BaseClassMemberValidator {
     required Set<InterfaceElement> subClasses,
   }) async {
     var superClasses =
-        elementClass.allSupertypes.map((e) => e.element2).toSet();
+        interfaceElement.allSupertypes.map((e) => e.element2).toSet();
     // check shadowing in the hierarchy
     var declarations = await searchEngine.searchMemberDeclarations(name);
     for (var declaration in declarations) {
@@ -201,12 +201,12 @@ class _CreateClassMemberValidator extends _BaseClassMemberValidator {
   _CreateClassMemberValidator(
       SearchEngine searchEngine,
       AnalysisSessionHelper sessionHelper,
-      ClassElement elementClass,
+      InterfaceElement interfaceElement,
       String name)
       : super(
           searchEngine,
           sessionHelper,
-          elementClass,
+          interfaceElement,
           ElementKind.METHOD,
           name,
         );
@@ -214,13 +214,13 @@ class _CreateClassMemberValidator extends _BaseClassMemberValidator {
   Future<RefactoringStatus> validate() async {
     _checkClassAlreadyDeclares();
     // do chained computations
-    var subClasses = await searchEngine.searchAllSubtypes(elementClass);
+    var subClasses = await searchEngine.searchAllSubtypes(interfaceElement);
     // check shadowing of class names
-    if (elementClass.name == name) {
+    if (interfaceElement.name == name) {
       result.addError(
         'Created ${elementKind.displayName} has the same name as the '
-        "declaring ${elementClass.kind.displayName} '$name'.",
-        newLocation_fromElement(elementClass),
+        "declaring ${interfaceElement.kind.displayName} '$name'.",
+        newLocation_fromElement(interfaceElement),
       );
     }
     // check shadowing in the hierarchy
@@ -274,7 +274,7 @@ class _RenameClassMemberValidator extends _BaseClassMemberValidator {
     _checkClassAlreadyDeclares();
     // do chained computations
     await _prepareReferences();
-    var subClasses = await searchEngine.searchAllSubtypes(elementClass);
+    var subClasses = await searchEngine.searchAllSubtypes(interfaceElement);
     // check shadowing of class names
     for (var element in elements) {
       var enclosingElement = element.enclosingElement3;

pkg/analysis_server/lib/src/services/refactoring/legacy/visible_ranges_computer.dart

@@ -37,7 +37,7 @@ class VisibleRangesComputer extends GeneralizingAstVisitor<void> {
     var loop = node.parent;
     if (loop != null) {
       for (var variable in node.variables.variables) {
-        _addLocalVariable(loop, variable.declaredElement);
+        _addLocalVariable(loop, variable.declaredElement2);
         variable.initializer?.accept(this);
       }
     }
@@ -47,7 +47,7 @@ class VisibleRangesComputer extends GeneralizingAstVisitor<void> {
   void visitFunctionDeclaration(FunctionDeclaration node) {
     var block = node.parent?.parent;
     if (block is Block) {
-      var element = node.declaredElement as FunctionElement;
+      var element = node.declaredElement2 as FunctionElement;
       _map[element] = range.node(block);
     }
 
@@ -59,7 +59,7 @@ class VisibleRangesComputer extends GeneralizingAstVisitor<void> {
     var block = node.parent;
     if (block != null) {
       for (var variable in node.variables.variables) {
-        _addLocalVariable(block, variable.declaredElement);
+        _addLocalVariable(block, variable.declaredElement2);
         variable.initializer?.accept(this);
       }
     }

pkg/analysis_server/lib/src/status/ast_writer.dart

@@ -43,10 +43,10 @@ class AstWriter extends UnifyingAstVisitor with TreeWriter {
       properties['static element'] = node.staticElement;
       properties['static type'] = node.staticType;
     } else if (node is ClassDeclaration) {
-      properties['declaredElement'] = node.declaredElement;
+      properties['declaredElement'] = node.declaredElement2;
       properties['abstract keyword'] = node.abstractKeyword;
     } else if (node is ClassTypeAlias) {
-      properties['declaredElement'] = node.declaredElement;
+      properties['declaredElement'] = node.declaredElement2;
       properties['abstract keyword'] = node.abstractKeyword;
     } else if (node is CompilationUnit) {
       properties['declaredElement'] = node.declaredElement;
@@ -55,7 +55,7 @@ class AstWriter extends UnifyingAstVisitor with TreeWriter {
     } else if (node is ConstructorName) {
       properties['static element'] = node.staticElement;
     } else if (node is DeclaredIdentifier) {
-      properties['element'] = node.declaredElement;
+      properties['element'] = node.declaredElement2;
       properties['keyword'] = node.keyword;
     } else if (node is ExportDirective) {
       properties['element'] = node.element2;
@@ -75,7 +75,7 @@ class AstWriter extends UnifyingAstVisitor with TreeWriter {
         properties['kind'] = 'unknown kind';
       }
     } else if (node is FunctionDeclaration) {
-      properties['declaredElement'] = node.declaredElement;
+      properties['declaredElement'] = node.declaredElement2;
       properties['external keyword'] = node.externalKeyword;
       properties['property keyword'] = node.propertyKeyword;
     } else if (node is FunctionExpressionInvocation) {
@@ -94,7 +94,7 @@ class AstWriter extends UnifyingAstVisitor with TreeWriter {
     } else if (node is LibraryDirective) {
       properties['element'] = node.element2;
     } else if (node is MethodDeclaration) {
-      properties['declaredElement'] = node.declaredElement;
+      properties['declaredElement'] = node.declaredElement2;
       properties['external keyword'] = node.externalKeyword;
       properties['modifier keyword'] = node.modifierKeyword;
       properties['operator keyword'] = node.operatorKeyword;
@@ -126,7 +126,7 @@ class AstWriter extends UnifyingAstVisitor with TreeWriter {
     } else if (node is VariableDeclarationList) {
       properties['keyword'] = node.keyword;
     } else if (node is Declaration) {
-      properties['declaredElement'] = node.declaredElement;
+      properties['declaredElement'] = node.declaredElement2;
     } else if (node is Expression) {
       properties['static type'] = node.staticType;
     } else if (node is FunctionBody) {

pkg/analysis_server/lib/src/utilities/extensions/ast.dart

@@ -24,7 +24,7 @@ extension AstNodeExtensions on AstNode {
   ExtensionElement? get enclosingExtensionElement {
     for (final node in withParents) {
       if (node is ExtensionDeclaration) {
-        return node.declaredElement;
+        return node.declaredElement2;
       }
     }
     return null;
@@ -46,9 +46,9 @@ extension AstNodeExtensions on AstNode {
   InterfaceElement? get enclosingInterfaceElement {
     for (final node in withParents) {
       if (node is ClassDeclaration) {
-        return node.declaredElement;
+        return node.declaredElement2;
       } else if (node is MixinDeclaration) {
-        return node.declaredElement;
+        return node.declaredElement2;
       }
     }
     return null;

pkg/analysis_server/test/services/refactoring/legacy/rename_constructor_test.dart

@@ -568,7 +568,7 @@ enum E {
 
 class _RenameConstructorTest extends RenameRefactoringTest {
   void _createConstructorDeclarationRefactoring(String search) {
-    var element = findNode.constructor(search).declaredElement;
+    var element = findNode.constructor(search).declaredElement2;
     createRenameRefactoringForElement(element);
   }
 

pkg/analysis_server/tool/bulk_fix/parse_utils.dart

@@ -29,7 +29,7 @@ class BulkFixDetails {
           .getResolvedUnit(file.absolute.path) as ResolvedUnitResult;
       for (var classDecl
           in resolvedFile.unit.declarations.whereType<ClassDeclaration>()) {
-        var classElement = classDecl.declaredElement;
+        var classElement = classDecl.declaredElement2;
         if (classElement != null &&
             classElement.allSupertypes.any(
                 (element) => element.element2.name == 'CorrectionProducer')) {

pkg/analysis_server/tool/code_completion/relevance_metrics.dart

@@ -968,7 +968,7 @@ class RelevanceDataCollector extends RecursiveAstVisitor<void> {
     // There are no completions.
     data.recordPercentage(
         'Methods with type parameters', node.typeParameters != null);
-    var element = node.declaredElement!;
+    var element = node.declaredElement2!;
     if (!element.isStatic && element.enclosingElement3 is ClassElement) {
       var overriddenMembers = inheritanceManager.getOverridden2(
           element.enclosingElement3 as ClassElement,
@@ -1488,12 +1488,12 @@ class RelevanceDataCollector extends RecursiveAstVisitor<void> {
     var node = reference;
     while (node != null) {
       if (node is MethodDeclaration) {
-        if (node.declaredElement == function) {
+        if (node.declaredElement2 == function) {
           return depth;
         }
         depth++;
       } else if (node is ConstructorDeclaration) {
-        if (node.declaredElement == function) {
+        if (node.declaredElement2 == function) {
           return depth;
         }
         depth++;

pkg/analyzer/CHANGELOG.md

@@ -1,6 +1,9 @@
 ## 4.5.0-dev
 * Update deprecation message for `FormalParameter.identifier`.
 * Deprecated `ClassOrMixinDeclaration`, use `ClassDeclaration` and `MixinDeclaration` directly.
+* Deprecate `Declaration.declaredElement`, use `declaredElement2` instead.
+  This is necessary to separate `ClassElement`, `EnumElement`, and `MixinElement`.
+  And, in the future, augmentations like `ClassAugmentationElement`, etc. 
 
 ## 4.4.0
 * Deprecated `ClassDeclaration.isAbstract`, use `abstractKeyword` instead.

pkg/analyzer/lib/dart/ast/ast.dart

@@ -863,7 +863,7 @@ abstract class ClassAugmentationDeclaration
   Token get augmentKeyword;
 
   @override
-  ClassAugmentationElement? get declaredElement;
+  ClassAugmentationElement? get declaredElement2;
 }
 
 /// The declaration of a class.
@@ -882,9 +882,13 @@ abstract class ClassDeclaration
         ClassOrAugmentationDeclaration,
         // ignore: deprecated_member_use_from_same_package
         ClassOrMixinDeclaration {
+  @Deprecated('Use declaredElement2 instead')
   @override
   ClassElement? get declaredElement;
 
+  @override
+  ClassElement? get declaredElement2;
+
   /// Returns the implements clause for the class/mixin, or `null` if the
   /// class/mixin does not implement any interfaces.
   @override
@@ -947,6 +951,9 @@ abstract class ClassOrAugmentationDeclaration
   /// Returns the token representing the 'class' keyword.
   Token get classKeyword;
 
+  @override
+  ClassOrAugmentationElement? get declaredElement2;
+
   /// Returns the `extends` clause for this class, or `null` if the class
   /// does not extend any other class.
   ///
@@ -1031,9 +1038,13 @@ abstract class ClassTypeAlias implements TypeAlias {
   /// defining an abstract class.
   Token? get abstractKeyword;
 
+  @Deprecated('Use declaredElement2 instead')
   @override
   ClassElement? get declaredElement;
 
+  @override
+  ClassElement? get declaredElement2;
+
   /// Return the token for the '=' separating the name from the definition.
   Token get equals;
 
@@ -1387,9 +1398,13 @@ abstract class ConstructorDeclaration implements ClassMember {
   /// not a const constructor.
   Token? get constKeyword;
 
+  @Deprecated('Use declaredElement2 instead')
   @override
   ConstructorElement? get declaredElement;
 
+  @override
+  ConstructorElement? get declaredElement2;
+
   /// Return the token for the 'external' keyword to the given [token].
   Token? get externalKeyword;
 
@@ -1567,7 +1582,13 @@ abstract class Declaration implements AnnotatedNode {
   /// Return the element associated with this declaration, or `null` if either
   /// this node corresponds to a list of declarations or if the AST structure
   /// has not been resolved.
+  @Deprecated('Use declaredElement2 instead')
   Element? get declaredElement;
+
+  /// Return the element associated with this declaration, or `null` if either
+  /// this node corresponds to a list of declarations or if the AST structure
+  /// has not been resolved.
+  Element? get declaredElement2;
 }
 
 /// The declaration of a single identifier.
@@ -1577,9 +1598,13 @@ abstract class Declaration implements AnnotatedNode {
 ///
 /// Clients may not extend, implement or mix-in this class.
 abstract class DeclaredIdentifier implements Declaration {
+  @Deprecated('Use declaredElement2 instead')
   @override
   LocalVariableElement? get declaredElement;
 
+  @override
+  LocalVariableElement? get declaredElement2;
+
   /// Return the name of the variable being declared.
   @Deprecated('Use name instead')
   SimpleIdentifier get identifier;
@@ -1793,9 +1818,13 @@ abstract class EnumDeclaration implements NamedCompilationUnitMember {
   /// Return the enumeration constants being declared.
   NodeList<EnumConstantDeclaration> get constants;
 
+  @Deprecated('Use declaredElement2 instead')
   @override
   ClassElement? get declaredElement;
 
+  @override
+  EnumElement? get declaredElement2;
+
   /// Return the 'enum' keyword.
   Token get enumKeyword;
 
@@ -1966,9 +1995,13 @@ abstract class ExtendsClause implements AstNode {
 ///
 /// Clients may not extend, implement or mix-in this class.
 abstract class ExtensionDeclaration implements CompilationUnitMember {
+  @Deprecated('Use declaredElement2 instead')
   @override
   ExtensionElement? get declaredElement;
 
+  @override
+  ExtensionElement? get declaredElement2;
+
   /// Return the type that is being extended.
   TypeAnnotation get extendedType;
 
@@ -2508,9 +2541,13 @@ abstract class FunctionBody implements AstNode {
 ///
 /// Clients may not extend, implement or mix-in this class.
 abstract class FunctionDeclaration implements NamedCompilationUnitMember {
+  @Deprecated('Use declaredElement2 instead')
   @override
   ExecutableElement? get declaredElement;
 
+  @override
+  ExecutableElement? get declaredElement2;
+
   /// Return the token representing the 'external' keyword, or `null` if this is
   /// not an external function.
   Token? get externalKeyword;
@@ -2627,9 +2664,13 @@ abstract class FunctionReference
 ///
 /// Clients may not extend, implement or mix-in this class.
 abstract class FunctionTypeAlias implements TypeAlias {
+  @Deprecated('Use declaredElement2 instead')
   @override
   TypeAliasElement? get declaredElement;
 
+  @override
+  TypeAliasElement? get declaredElement2;
+
   /// Return the parameters associated with the function type.
   FormalParameterList get parameters;
 
@@ -3424,9 +3465,13 @@ abstract class MethodDeclaration implements ClassMember {
   /// Return the body of the method.
   FunctionBody get body;
 
+  @Deprecated('Use declaredElement2 instead')
   @override
   ExecutableElement? get declaredElement;
 
+  @override
+  ExecutableElement? get declaredElement2;
+
   /// Return the token for the 'external' keyword, or `null` if the constructor
   /// is not external.
   Token? get externalKeyword;
@@ -3552,7 +3597,7 @@ abstract class MixinAugmentationDeclaration
   Token get augmentKeyword;
 
   @override
-  MixinAugmentationElement? get declaredElement;
+  MixinAugmentationElement? get declaredElement2;
 }
 
 /// The declaration of a mixin.
@@ -3567,13 +3612,13 @@ abstract class MixinDeclaration
         MixinOrAugmentationDeclaration,
         // ignore: deprecated_member_use_from_same_package
         ClassOrMixinDeclaration {
-  // TODO(scheglov) Uncomment when removed [ClassOrMixinDeclaration].
-  // @override
-  // MixinElement get declaredElement;
-
+  @Deprecated('Use declaredElement2 instead')
   @override
   ClassElement? get declaredElement;
 
+  @override
+  MixinElement? get declaredElement2;
+
   /// Returns the implements clause for the class/mixin, or `null` if the
   /// class/mixin does not implement any interfaces.
   @override
@@ -3604,14 +3649,13 @@ abstract class MixinDeclaration
 @experimental
 abstract class MixinOrAugmentationDeclaration
     implements NamedCompilationUnitMember {
+  @override
+  MixinOrAugmentationElement? get declaredElement2;
+
   /// Returns the `implements` clause for the mixin, or `null` if the mixin
   /// does not implement any interfaces.
   ImplementsClause? get implementsClause;
 
-  // @override
-  // TODO(scheglov) Uncomment when removed [ClassOrMixinDeclaration].
-  // MixinOrAugmentationElement get declaredElement;
-
   /// Returns the left curly bracket.
   Token get leftBracket;
 
@@ -4827,9 +4871,13 @@ abstract class TypeParameter implements Declaration {
   /// explicit upper bound.
   TypeAnnotation? get bound;
 
+  @Deprecated('Use declaredElement2 instead')
   @override
   TypeParameterElement? get declaredElement;
 
+  @override
+  TypeParameterElement? get declaredElement2;
+
   /// Return the token representing the 'extends' keyword, or `null` if there is
   /// no explicit upper bound.
   Token? get extendsKeyword;
@@ -4906,9 +4954,13 @@ abstract class UriBasedDirective implements Directive {
 // Consider changing the class hierarchy so that [VariableDeclaration] does not
 // extend [Declaration].
 abstract class VariableDeclaration implements Declaration {
+  @Deprecated('Use declaredElement2 instead')
   @override
   VariableElement? get declaredElement;
 
+  @override
+  VariableElement? get declaredElement2;
+
   /// Return the equal sign separating the variable name from the initial value,
   /// or `null` if the initial value was not specified.
   Token? get equals;

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

@@ -446,7 +446,7 @@ class _IndexContributor extends GeneralizingAstVisitor {
 
   _IndexContributor(this.assembler);
 
-  void recordIsAncestorOf(ClassElement descendant) {
+  void recordIsAncestorOf(InterfaceElement descendant) {
     _recordIsAncestorOf(descendant, descendant, false, <ClassElement>[]);
   }
 
@@ -561,7 +561,7 @@ class _IndexContributor extends GeneralizingAstVisitor {
   @override
   void visitClassDeclaration(ClassDeclaration node) {
     _addSubtypeForClassDeclaration(node);
-    var declaredElement = node.declaredElement!;
+    var declaredElement = node.declaredElement2!;
     if (node.extendsClause == null) {
       final objectElement = declaredElement.supertype?.element2;
       recordRelationOffset(objectElement, IndexRelationKind.IS_EXTENDED_BY,
@@ -574,7 +574,7 @@ class _IndexContributor extends GeneralizingAstVisitor {
   @override
   void visitClassTypeAlias(ClassTypeAlias node) {
     _addSubtypeForClassTypeAlis(node);
-    recordIsAncestorOf(node.declaredElement!);
+    recordIsAncestorOf(node.declaredElement2!);
     super.visitClassTypeAlias(node);
   }
 
@@ -681,7 +681,7 @@ class _IndexContributor extends GeneralizingAstVisitor {
       memberNodes: node.members,
     );
 
-    var declaredElement = node.declaredElement!;
+    var declaredElement = node.declaredElement2!;
     recordIsAncestorOf(declaredElement);
     super.visitEnumDeclaration(node);
   }
@@ -770,7 +770,7 @@ class _IndexContributor extends GeneralizingAstVisitor {
   @override
   void visitMixinDeclaration(MixinDeclaration node) {
     _addSubtypeForMixinDeclaration(node);
-    recordIsAncestorOf(node.declaredElement!);
+    recordIsAncestorOf(node.declaredElement2!);
     super.visitMixinDeclaration(node);
   }
 

pkg/analyzer/lib/src/dart/ast/ast.dart

@@ -1714,7 +1714,7 @@ class ClassDeclarationImpl extends ClassOrMixinDeclarationImpl
   NativeClauseImpl? _nativeClause;
 
   @override
-  ClassElement? declaredElement;
+  ClassElement? declaredElement2;
 
   /// Initialize a newly created class declaration. Either or both of the
   /// [comment] and [metadata] can be `null` if the class does not have the
@@ -1745,6 +1745,10 @@ class ClassDeclarationImpl extends ClassOrMixinDeclarationImpl
     _becomeParentOf(_withClause);
   }
 
+  @Deprecated('Use declaredElement2 instead')
+  @override
+  ClassElement? get declaredElement => declaredElement2;
+
   @override
   ExtendsClauseImpl? get extendsClause => _extendsClause;
 
@@ -1978,7 +1982,7 @@ class ClassTypeAliasImpl extends TypeAliasImpl implements ClassTypeAlias {
   ImplementsClauseImpl? _implementsClause;
 
   @override
-  ClassElement? declaredElement;
+  ClassElement? declaredElement2;
 
   /// Initialize a newly created class type alias. Either or both of the
   /// [comment] and [metadata] can be `null` if the class type alias does not
@@ -2010,6 +2014,10 @@ class ClassTypeAliasImpl extends TypeAliasImpl implements ClassTypeAlias {
     _becomeParentOf(_implementsClause);
   }
 
+  @Deprecated('Use declaredElement2 instead')
+  @override
+  ClassElement? get declaredElement => declaredElement2;
+
   @override
   Token get firstTokenAfterCommentAndMetadata {
     return abstractKeyword ?? macroKeyword ?? augmentKeyword ?? typedefKeyword;
@@ -2784,7 +2792,7 @@ class ConstructorDeclarationImpl extends ClassMemberImpl
   /// structure has not been resolved or if this constructor could not be
   /// resolved.
   @override
-  ConstructorElement? declaredElement;
+  ConstructorElement? declaredElement2;
 
   /// Initialize a newly created constructor declaration. The [externalKeyword]
   /// can be `null` if the constructor is not external. Either or both of the
@@ -2833,6 +2841,10 @@ class ConstructorDeclarationImpl extends ClassMemberImpl
     _body = _becomeParentOf(functionBody as FunctionBodyImpl);
   }
 
+  @Deprecated('Use declaredElement2 instead')
+  @override
+  ConstructorElement? get declaredElement => declaredElement2;
+
   @override
   Token get endToken {
     return _body.endToken;
@@ -3268,7 +3280,7 @@ class DeclaredIdentifierImpl extends DeclarationImpl
   SimpleIdentifierImpl _identifier;
 
   @override
-  LocalVariableElement? declaredElement;
+  LocalVariableElement? declaredElement2;
 
   /// Initialize a newly created formal parameter. Either or both of the
   /// [comment] and [metadata] can be `null` if the declaration does not have
@@ -3286,6 +3298,10 @@ class DeclaredIdentifierImpl extends DeclarationImpl
     _becomeParentOf(_identifier);
   }
 
+  @Deprecated('Use declaredElement2 instead')
+  @override
+  LocalVariableElement? get declaredElement => declaredElement2;
+
   @override
   Token get endToken => _identifier.endToken;
 
@@ -3801,7 +3817,7 @@ class EnumConstantDeclarationImpl extends DeclarationImpl
   SimpleIdentifierImpl _name;
 
   @override
-  FieldElement? declaredElement;
+  FieldElement? declaredElement2;
 
   @override
   final EnumConstantArgumentsImpl? arguments;
@@ -3822,6 +3838,10 @@ class EnumConstantDeclarationImpl extends DeclarationImpl
     _becomeParentOf(arguments);
   }
 
+  @Deprecated('Use declaredElement2 instead')
+  @override
+  FieldElement? get declaredElement => declaredElement2;
+
   @override
   Token get endToken => (arguments ?? _name).endToken;
 
@@ -3902,7 +3922,7 @@ class EnumDeclarationImpl extends NamedCompilationUnitMemberImpl
   Token rightBracket;
 
   @override
-  ClassElement? declaredElement;
+  EnumElement? declaredElement2;
 
   /// Initialize a newly created enumeration declaration. Either or both of the
   /// [comment] and [metadata] can be `null` if the declaration does not have
@@ -3934,6 +3954,10 @@ class EnumDeclarationImpl extends NamedCompilationUnitMemberImpl
   @override
   NodeListImpl<EnumConstantDeclaration> get constants => _constants;
 
+  @Deprecated('Use declaredElement2 instead')
+  @override
+  ClassElement? get declaredElement => declaredElement2 as ClassElement?;
+
   @override
   Token get endToken => rightBracket;
 
@@ -4427,7 +4451,8 @@ class ExtensionDeclarationImpl extends CompilationUnitMemberImpl
   @override
   Token rightBracket;
 
-  ExtensionElement? _declaredElement;
+  @override
+  ExtensionElement? declaredElement2;
 
   ExtensionDeclarationImpl({
     required super.comment,
@@ -4454,13 +4479,9 @@ class ExtensionDeclarationImpl extends CompilationUnitMemberImpl
     _members._initialize(this, members);
   }
 
+  @Deprecated('Use declaredElement2 instead')
   @override
-  ExtensionElement? get declaredElement => _declaredElement;
-
-  /// Set the element declared by this declaration to the given [element].
-  set declaredElement(ExtensionElement? element) {
-    _declaredElement = element;
-  }
+  ExtensionElement? get declaredElement => declaredElement2;
 
   @override
   Token get endToken => rightBracket;
@@ -4687,6 +4708,9 @@ class FieldDeclarationImpl extends ClassMemberImpl implements FieldDeclaration {
   @override
   Element? get declaredElement => null;
 
+  @override
+  Element? get declaredElement2 => null;
+
   @override
   Token get endToken => semicolon;
 
@@ -5519,7 +5543,7 @@ class FunctionDeclarationImpl extends NamedCompilationUnitMemberImpl
   FunctionExpressionImpl _functionExpression;
 
   @override
-  ExecutableElement? declaredElement;
+  ExecutableElement? declaredElement2;
 
   /// Initialize a newly created function declaration. Either or both of the
   /// [comment] and [metadata] can be `null` if the function does not have the
@@ -5542,6 +5566,10 @@ class FunctionDeclarationImpl extends NamedCompilationUnitMemberImpl
     _becomeParentOf(_functionExpression);
   }
 
+  @Deprecated('Use declaredElement2 instead')
+  @override
+  ExecutableElement? get declaredElement => declaredElement2;
+
   @override
   Token get endToken => _functionExpression.endToken;
 
@@ -5881,7 +5909,7 @@ class FunctionTypeAliasImpl extends TypeAliasImpl implements FunctionTypeAlias {
   FormalParameterListImpl _parameters;
 
   @override
-  TypeAliasElement? declaredElement;
+  TypeAliasElement? declaredElement2;
 
   /// Initialize a newly created function type alias. Either or both of the
   /// [comment] and [metadata] can be `null` if the function does not have the
@@ -5905,6 +5933,10 @@ class FunctionTypeAliasImpl extends TypeAliasImpl implements FunctionTypeAlias {
     _becomeParentOf(_parameters);
   }
 
+  @Deprecated('Use declaredElement2 instead')
+  @override
+  TypeAliasElement? get declaredElement => declaredElement2;
+
   @override
   FormalParameterListImpl get parameters => _parameters;
 
@@ -6199,7 +6231,7 @@ class GenericTypeAliasImpl extends TypeAliasImpl implements GenericTypeAlias {
   Token equals;
 
   @override
-  Element? declaredElement;
+  Element? declaredElement2;
 
   /// Returns a newly created generic type alias. Either or both of the
   /// [comment] and [metadata] can be `null` if the variable list does not have
@@ -6220,6 +6252,10 @@ class GenericTypeAliasImpl extends TypeAliasImpl implements GenericTypeAlias {
     _becomeParentOf(_type);
   }
 
+  @Deprecated('Use declaredElement2 instead')
+  @override
+  Element? get declaredElement => declaredElement2;
+
   /// The type of function being defined by the alias.
   ///
   /// If the non-function type aliases feature is enabled, a type alias may have
@@ -7956,7 +7992,7 @@ class MethodDeclarationImpl extends ClassMemberImpl
   /// a [PropertyAccessorElement] if this represents the declaration of either a
   /// getter or a setter.
   @override
-  ExecutableElement? declaredElement;
+  ExecutableElement? declaredElement2;
 
   /// Initialize a newly created method declaration. Either or both of the
   /// [comment] and [metadata] can be `null` if the declaration does not have
@@ -7998,6 +8034,10 @@ class MethodDeclarationImpl extends ClassMemberImpl
     _body = _becomeParentOf(functionBody as FunctionBodyImpl);
   }
 
+  @Deprecated('Use declaredElement2 instead')
+  @override
+  ExecutableElement? get declaredElement => declaredElement2;
+
   @override
   Token get endToken => _body.endToken;
 
@@ -8263,7 +8303,7 @@ class MixinDeclarationImpl extends ClassOrMixinDeclarationImpl
   OnClauseImpl? _onClause;
 
   @override
-  ClassElement? declaredElement;
+  MixinElement? declaredElement2;
 
   /// Initialize a newly created mixin declaration. Either or both of the
   /// [comment] and [metadata] can be `null` if the mixin does not have the
@@ -8288,6 +8328,10 @@ class MixinDeclarationImpl extends ClassOrMixinDeclarationImpl
     _becomeParentOf(_onClause);
   }
 
+  @Deprecated('Use declaredElement2 instead')
+  @override
+  ClassElement? get declaredElement => declaredElement2 as ClassElement?;
+
   @override
   Token get firstTokenAfterCommentAndMetadata {
     return mixinKeyword;
@@ -11334,6 +11378,9 @@ class TopLevelVariableDeclarationImpl extends CompilationUnitMemberImpl
   @override
   Element? get declaredElement => null;
 
+  @override
+  Element? get declaredElement2 => null;
+
   @override
   Token get endToken => semicolon;
 
@@ -11665,7 +11712,7 @@ class TypeParameterImpl extends DeclarationImpl implements TypeParameter {
   TypeAnnotationImpl? _bound;
 
   @override
-  TypeParameterElement? declaredElement;
+  TypeParameterElement? declaredElement2;
 
   /// Initialize a newly created type parameter. Either or both of the [comment]
   /// and [metadata] can be `null` if the parameter does not have the
@@ -11691,6 +11738,10 @@ class TypeParameterImpl extends DeclarationImpl implements TypeParameter {
     _bound = _becomeParentOf(type as TypeAnnotationImpl?);
   }
 
+  @Deprecated('Use declaredElement2 instead')
+  @override
+  TypeParameterElement? get declaredElement => declaredElement2;
+
   @override
   Token get endToken {
     if (_bound == null) {
@@ -11884,7 +11935,7 @@ class VariableDeclarationImpl extends DeclarationImpl
   SimpleIdentifierImpl _name;
 
   @override
-  VariableElement? declaredElement;
+  VariableElement? declaredElement2;
 
   /// The equal sign separating the variable name from the initial value, or
   /// `null` if the initial value was not specified.
@@ -11914,6 +11965,10 @@ class VariableDeclarationImpl extends DeclarationImpl
     _becomeParentOf(_initializer);
   }
 
+  @Deprecated('Use declaredElement2 instead')
+  @override
+  VariableElement? get declaredElement => declaredElement2;
+
   /// This overridden implementation of [documentationComment] looks in the
   /// grandparent node for Dartdoc comments if no documentation is specifically
   /// available on the node.

pkg/analyzer/lib/src/dart/ast/element_locator.dart

@@ -38,7 +38,7 @@ class _ElementMapper extends GeneralizingAstVisitor<Element> {
 
   @override
   Element? visitClassDeclaration(ClassDeclaration node) {
-    return node.declaredElement;
+    return node.declaredElement2;
   }
 
   @override
@@ -48,7 +48,7 @@ class _ElementMapper extends GeneralizingAstVisitor<Element> {
 
   @override
   Element? visitConstructorDeclaration(ConstructorDeclaration node) {
-    return node.declaredElement;
+    return node.declaredElement2;
   }
 
   @override
@@ -75,17 +75,17 @@ class _ElementMapper extends GeneralizingAstVisitor<Element> {
 
   @override
   Element? visitFunctionDeclaration(FunctionDeclaration node) {
-    return node.declaredElement;
+    return node.declaredElement2;
   }
 
   @override
   Element? visitFunctionTypeAlias(FunctionTypeAlias node) {
-    return node.declaredElement;
+    return node.declaredElement2;
   }
 
   @override
   Element? visitGenericTypeAlias(GenericTypeAlias node) {
-    return node.declaredElement;
+    return node.declaredElement2;
   }
 
   @override
@@ -103,14 +103,14 @@ class _ElementMapper extends GeneralizingAstVisitor<Element> {
       if (identical(returnType, node)) {
         var name = parent.name2;
         if (name != null) {
-          return parent.declaredElement;
+          return parent.declaredElement2;
         }
         var element = node.staticElement;
         if (element is ClassElement) {
           return element.unnamedConstructor;
         }
       } else if (parent.name2 == node.endToken) {
-        return parent.declaredElement;
+        return parent.declaredElement2;
       }
     } else if (parent is LibraryIdentifier) {
       var grandParent = parent.parent;
@@ -148,7 +148,7 @@ class _ElementMapper extends GeneralizingAstVisitor<Element> {
 
   @override
   Element? visitMethodDeclaration(MethodDeclaration node) {
-    return node.declaredElement;
+    return node.declaredElement2;
   }
 
   @override
@@ -194,11 +194,11 @@ class _ElementMapper extends GeneralizingAstVisitor<Element> {
 
   @override
   Element? visitTypeParameter(TypeParameter node) {
-    return node.declaredElement;
+    return node.declaredElement2;
   }
 
   @override
   Element? visitVariableDeclaration(VariableDeclaration node) {
-    return node.declaredElement;
+    return node.declaredElement2;
   }
 }

pkg/analyzer/lib/src/dart/constant/constant_verifier.dart

@@ -132,7 +132,7 @@ class ConstantVerifier extends RecursiveAstVisitor<void> {
       _validateConstantArguments(argumentList);
     }
 
-    var element = node.declaredElement as ConstFieldElementImpl;
+    var element = node.declaredElement2 as ConstFieldElementImpl;
     var result = element.evaluationResult;
     if (result != null) {
       _reportErrors(result.errors, null);
@@ -290,7 +290,7 @@ class ConstantVerifier extends RecursiveAstVisitor<void> {
     super.visitVariableDeclaration(node);
     var initializer = node.initializer;
     if (initializer != null && (node.isConst || node.isFinal)) {
-      var element = node.declaredElement as VariableElementImpl;
+      var element = node.declaredElement2 as VariableElementImpl;
       var result = element.evaluationResult;
       if (result == null) {
         // Variables marked "const" should have had their values computed by
@@ -1090,7 +1090,7 @@ extension on Expression {
               !declarationListParent.isStatic) {
             var container = declarationListParent.parent;
             if (container is ClassDeclaration) {
-              var enclosingClass = container.declaredElement;
+              var enclosingClass = container.declaredElement2;
               if (enclosingClass != null) {
                 // A field initializer of a class with at least one generative
                 // const constructor does not constitute a constant context, but

pkg/analyzer/lib/src/dart/constant/utilities.dart

@@ -106,7 +106,7 @@ class ConstantFinder extends RecursiveAstVisitor<void> {
   @override
   void visitClassDeclaration(ClassDeclaration node) {
     bool prevTreatFinalInstanceVarAsConst = treatFinalInstanceVarAsConst;
-    if (node.declaredElement!.constructors
+    if (node.declaredElement2!.constructors
         .any((ConstructorElement e) => e.isConst)) {
       // Instance vars marked "final" need to be included in the dependency
       // graph, since constant constructors implicitly use the values in their
@@ -124,7 +124,7 @@ class ConstantFinder extends RecursiveAstVisitor<void> {
   void visitConstructorDeclaration(ConstructorDeclaration node) {
     super.visitConstructorDeclaration(node);
     if (node.constKeyword != null) {
-      var element = node.declaredElement;
+      var element = node.declaredElement2;
       if (element != null) {
         constantsToCompute.add(element);
         constantsToCompute.addAll(element.parameters);
@@ -145,7 +145,7 @@ class ConstantFinder extends RecursiveAstVisitor<void> {
   void visitEnumConstantDeclaration(EnumConstantDeclaration node) {
     super.visitEnumConstantDeclaration(node);
 
-    var element = node.declaredElement as ConstFieldElementImpl;
+    var element = node.declaredElement2 as ConstFieldElementImpl;
     constantsToCompute.add(element);
 
     var constantInitializer = element.constantInitializer!;
@@ -156,7 +156,7 @@ class ConstantFinder extends RecursiveAstVisitor<void> {
   void visitVariableDeclaration(VariableDeclaration node) {
     super.visitVariableDeclaration(node);
     var initializer = node.initializer;
-    var element = node.declaredElement!;
+    var element = node.declaredElement2!;
     if (initializer != null &&
         (node.isConst ||
             treatFinalInstanceVarAsConst &&

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

@@ -11,7 +11,7 @@ import 'package:analyzer/src/dart/element/type_system.dart';
 class ClassHierarchy {
   final Map<InterfaceElement, _Hierarchy> _map = {};
 
-  List<ClassHierarchyError> errors(ClassElement element) {
+  List<ClassHierarchyError> errors(InterfaceElement element) {
     return _getHierarchy(element).errors;
   }
 

pkg/analyzer/lib/src/dart/element/inheritance_manager3.dart

@@ -299,7 +299,7 @@ class InheritanceManager3 {
   /// Return all members of mixins, superclasses, and interfaces that a member
   /// with the given [name], defined in the [element], would override; or `null`
   /// if no members would be overridden.
-  List<ExecutableElement>? getOverridden2(ClassElement element, Name name) {
+  List<ExecutableElement>? getOverridden2(InterfaceElement element, Name name) {
     var interface = getInterface(element);
     return interface._overridden[name];
   }

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

@@ -8,14 +8,6 @@ import 'package:analyzer/src/dart/element/element.dart';
 import 'package:analyzer/src/summary2/combinator.dart';
 import 'package:analyzer/src/summary2/export.dart';
 
-/// The scope defined by a class.
-class ClassScope extends EnclosedScope {
-  ClassScope(super.parent, ClassElement element) {
-    element.accessors.forEach(_addPropertyAccessor);
-    element.methods.forEach(_addGetter);
-  }
-}
-
 /// The scope for the initializers in a constructor.
 class ConstructorInitializerScope extends EnclosedScope {
   ConstructorInitializerScope(super.parent, ConstructorElement element) {
@@ -107,6 +99,14 @@ class ImportedElement {
   });
 }
 
+/// The scope defined by an interface element.
+class InterfaceScope extends EnclosedScope {
+  InterfaceScope(super.parent, InterfaceElement element) {
+    element.accessors.forEach(_addPropertyAccessor);
+    element.methods.forEach(_addGetter);
+  }
+}
+
 class LibraryOrAugmentationScope extends EnclosedScope {
   final LibraryOrAugmentationElementImpl _container;
   final List<ExtensionElement> extensions = [];

pkg/analyzer/lib/src/dart/micro/utils.dart

@@ -277,7 +277,7 @@ class ReferencesCollector extends GeneralizingAstVisitor<void> {
 
   @override
   visitConstructorDeclaration(ConstructorDeclaration node) {
-    var e = node.declaredElement;
+    var e = node.declaredElement2;
     if (e == element) {
       if (e!.name.isEmpty) {
         references.add(

pkg/analyzer/lib/src/dart/resolver/flow_analysis_visitor.dart

@@ -280,7 +280,7 @@ class FlowAnalysisHelper {
       var variables = node.variables;
       for (var i = 0; i < variables.length; ++i) {
         var variable = variables[i];
-        flow!.declare(variable.declaredElement as PromotableElement,
+        flow!.declare(variable.declaredElement2 as PromotableElement,
             variable.initializer != null);
       }
     }
@@ -627,7 +627,7 @@ class _AssignedVariablesVisitor extends RecursiveAstVisitor<void> {
         grandParent is FieldDeclaration) {
       throw StateError('Should not visit top level declarations');
     }
-    var declaredElement = node.declaredElement as PromotableElement;
+    var declaredElement = node.declaredElement2 as PromotableElement;
     assignedVariables.declare(declaredElement);
     if (declaredElement.isLate && node.initializer != null) {
       assignedVariables.beginNode();
@@ -678,7 +678,7 @@ class _AssignedVariablesVisitor extends RecursiveAstVisitor<void> {
           assignedVariables.write(element);
         }
       } else if (forLoopParts is ForEachPartsWithDeclaration) {
-        var variable = forLoopParts.loopVariable.declaredElement!;
+        var variable = forLoopParts.loopVariable.declaredElement2!;
         assignedVariables.declare(variable);
       } else {
         throw StateError('Unrecognized for loop parts');

pkg/analyzer/lib/src/dart/resolver/for_resolver.dart

@@ -132,12 +132,13 @@ class ForResolver {
         elementType != null &&
         loopVariable.type == null) {
       var loopVariableElement =
-          loopVariable.declaredElement as LocalVariableElementImpl;
+          loopVariable.declaredElement2 as LocalVariableElementImpl;
       loopVariableElement.type = elementType;
     }
 
     if (loopVariable != null) {
-      _resolver.flowAnalysis.flow?.declare(loopVariable.declaredElement!, true);
+      _resolver.flowAnalysis.flow
+          ?.declare(loopVariable.declaredElement2!, true);
     }
 
     _resolver.flowAnalysis.flow?.forEach_bodyBegin(node);

pkg/analyzer/lib/src/dart/resolver/function_expression_resolver.dart

@@ -162,7 +162,7 @@ class FunctionExpressionResolver {
     }
 
     return type.instantiate(typeParameters.map((typeParameter) {
-      return typeParameter.declaredElement!.instantiate(
+      return typeParameter.declaredElement2!.instantiate(
         nullabilitySuffix: _resolver.noneOrStarSuffix,
       );
     }).toList());

pkg/analyzer/lib/src/dart/resolver/legacy_type_asserter.dart

@@ -50,7 +50,7 @@ class LegacyTypeAsserter extends GeneralizingAstVisitor<void> {
 
   @override
   void visitClassMember(ClassMember node) {
-    final element = node.declaredElement;
+    final element = node.declaredElement2;
     if (element is ExecutableElement) {
       _assertLegacyType(element.type);
     }
@@ -66,7 +66,7 @@ class LegacyTypeAsserter extends GeneralizingAstVisitor<void> {
 
   @override
   void visitDeclaredIdentifier(DeclaredIdentifier node) {
-    _assertLegacyType(node.declaredElement?.type);
+    _assertLegacyType(node.declaredElement2?.type);
     super.visitDeclaredIdentifier(node);
   }
 
@@ -85,7 +85,7 @@ class LegacyTypeAsserter extends GeneralizingAstVisitor<void> {
 
   @override
   void visitFunctionDeclaration(FunctionDeclaration node) {
-    _assertLegacyType(node.declaredElement?.type);
+    _assertLegacyType(node.declaredElement2?.type);
     super.visitFunctionDeclaration(node);
   }
 
@@ -110,7 +110,7 @@ class LegacyTypeAsserter extends GeneralizingAstVisitor<void> {
 
   @override
   void visitVariableDeclaration(VariableDeclaration node) {
-    _assertLegacyType(node.declaredElement?.type);
+    _assertLegacyType(node.declaredElement2?.type);
     super.visitVariableDeclaration(node);
   }
 

pkg/analyzer/lib/src/dart/resolver/resolution_visitor.dart

@@ -240,7 +240,7 @@ class ResolutionVisitor extends RecursiveAstVisitor<void> {
   @override
   void visitClassDeclaration(covariant ClassDeclarationImpl node) {
     ClassElementImpl element = _elementWalker!.getClass();
-    node.declaredElement = element;
+    node.declaredElement2 = element;
     _namedTypeResolver.enclosingClass = element;
 
     _setOrCreateMetadataElements(element, node.metadata);
@@ -275,7 +275,7 @@ class ResolutionVisitor extends RecursiveAstVisitor<void> {
   @override
   void visitClassTypeAlias(covariant ClassTypeAliasImpl node) {
     ClassElementImpl element = _elementWalker!.getClass();
-    node.declaredElement = element;
+    node.declaredElement2 = element;
     _namedTypeResolver.enclosingClass = element;
 
     _setOrCreateMetadataElements(element, node.metadata);
@@ -302,8 +302,8 @@ class ResolutionVisitor extends RecursiveAstVisitor<void> {
   @override
   void visitConstructorDeclaration(ConstructorDeclaration node) {
     ConstructorElementImpl element = _elementWalker!.getConstructor();
-    (node as ConstructorDeclarationImpl).declaredElement = element;
-    node.declaredElement = element;
+    (node as ConstructorDeclarationImpl).declaredElement2 = element;
+    node.declaredElement2 = element;
 
     _setOrCreateMetadataElements(element, node.metadata);
 
@@ -333,7 +333,7 @@ class ResolutionVisitor extends RecursiveAstVisitor<void> {
     var nameToken = node.name;
     var element = LocalVariableElementImpl(nameToken.lexeme, nameToken.offset);
     _elementHolder.enclose(element);
-    node.declaredElement = element;
+    node.declaredElement2 = element;
 
     _setOrCreateMetadataElements(element, node.metadata);
 
@@ -408,7 +408,7 @@ class ResolutionVisitor extends RecursiveAstVisitor<void> {
   void visitEnumConstantDeclaration(
       covariant EnumConstantDeclarationImpl node) {
     var element = _elementWalker!.getVariable() as ConstFieldElementImpl;
-    node.declaredElement = element;
+    node.declaredElement2 = element;
 
     _setOrCreateMetadataElements(element, node.metadata);
 
@@ -425,7 +425,7 @@ class ResolutionVisitor extends RecursiveAstVisitor<void> {
   @override
   void visitEnumDeclaration(covariant EnumDeclarationImpl node) {
     EnumElementImpl element = _elementWalker!.getEnum();
-    node.declaredElement = element;
+    node.declaredElement2 = element;
     _namedTypeResolver.enclosingClass = element;
 
     _setOrCreateMetadataElements(element, node.metadata);
@@ -463,8 +463,8 @@ class ResolutionVisitor extends RecursiveAstVisitor<void> {
   @override
   void visitExtensionDeclaration(ExtensionDeclaration node) {
     var element = _elementWalker!.getExtension();
-    (node as ExtensionDeclarationImpl).declaredElement = element;
-    node.declaredElement = element;
+    (node as ExtensionDeclarationImpl).declaredElement2 = element;
+    node.declaredElement2 = element;
 
     _setOrCreateMetadataElements(element, node.metadata);
 
@@ -546,9 +546,9 @@ class ResolutionVisitor extends RecursiveAstVisitor<void> {
       element = node.isGetter || node.isSetter
           ? _elementWalker!.getAccessor()
           : _elementWalker!.getFunction();
-      node.declaredElement = element;
+      node.declaredElement2 = element;
     } else {
-      element = node.declaredElement as ExecutableElementImpl;
+      element = node.declaredElement2 as ExecutableElementImpl;
 
       _setCodeRange(element, node);
       setElementDocumentationComment(element, node);
@@ -646,7 +646,7 @@ class ResolutionVisitor extends RecursiveAstVisitor<void> {
   @override
   void visitFunctionTypeAlias(covariant FunctionTypeAliasImpl node) {
     var element = _elementWalker!.getTypedef();
-    node.declaredElement = element;
+    node.declaredElement2 = element;
 
     _setOrCreateMetadataElements(element, node.metadata);
 
@@ -760,7 +760,7 @@ class ResolutionVisitor extends RecursiveAstVisitor<void> {
   @override
   void visitGenericTypeAlias(covariant GenericTypeAliasImpl node) {
     var element = _elementWalker!.getTypedef();
-    node.declaredElement = element;
+    node.declaredElement2 = element;
 
     _setOrCreateMetadataElements(element, node.metadata);
 
@@ -862,7 +862,7 @@ class ResolutionVisitor extends RecursiveAstVisitor<void> {
     ExecutableElementImpl element = node.isGetter || node.isSetter
         ? _elementWalker!.getAccessor()
         : _elementWalker!.getFunction();
-    node.declaredElement = element;
+    node.declaredElement2 = element;
 
     _setOrCreateMetadataElements(element, node.metadata);
 
@@ -897,7 +897,7 @@ class ResolutionVisitor extends RecursiveAstVisitor<void> {
   @override
   void visitMixinDeclaration(covariant MixinDeclarationImpl node) {
     var element = _elementWalker!.getMixin();
-    node.declaredElement = element;
+    node.declaredElement2 = element as MixinElementImpl;
 
     _setOrCreateMetadataElements(element, node.metadata);
 
@@ -1089,7 +1089,7 @@ class ResolutionVisitor extends RecursiveAstVisitor<void> {
 
   @override
   void visitTypeParameter(TypeParameter node) {
-    var element = node.declaredElement as TypeParameterElementImpl;
+    var element = node.declaredElement2 as TypeParameterElementImpl;
 
     _setOrCreateMetadataElements(element, node.metadata);
 
@@ -1109,9 +1109,9 @@ class ResolutionVisitor extends RecursiveAstVisitor<void> {
     VariableElementImpl element;
     if (_elementWalker != null) {
       element = _elementWalker!.getVariable();
-      node.declaredElement = element;
+      node.declaredElement2 = element;
     } else {
-      var localElement = node.declaredElement as LocalVariableElementImpl;
+      var localElement = node.declaredElement2 as LocalVariableElementImpl;
       element = localElement;
 
       var varList = node.parent as VariableDeclarationList;
@@ -1153,7 +1153,7 @@ class ResolutionVisitor extends RecursiveAstVisitor<void> {
     var variables = node.variables;
     for (var i = 0; i < variables.length; i++) {
       var variable = variables[i];
-      var element = variable.declaredElement as ElementImpl;
+      var element = variable.declaredElement2 as ElementImpl;
       _setOrCreateMetadataElements(element, annotations, visitNodes: false);
 
       var offset = (i == 0 ? node.parent! : variable).offset;
@@ -1195,7 +1195,7 @@ class ResolutionVisitor extends RecursiveAstVisitor<void> {
     var node = statement.functionDeclaration;
     var nameToken = node.name2;
     var element = FunctionElementImpl(nameToken.lexeme, nameToken.offset);
-    node.declaredElement = element;
+    node.declaredElement2 = element;
     _define(element);
     _elementHolder.enclose(element);
   }
@@ -1220,7 +1220,7 @@ class ResolutionVisitor extends RecursiveAstVisitor<void> {
           nameToken.offset,
         );
       }
-      variable.declaredElement = element;
+      variable.declaredElement2 = element;
       _elementHolder.enclose(element);
       _define(element);
 
@@ -1249,7 +1249,7 @@ class ResolutionVisitor extends RecursiveAstVisitor<void> {
 
         _setCodeRange(element, typeParameter);
       }
-      typeParameter.declaredElement = element;
+      typeParameter.declaredElement2 = element;
       // ignore: deprecated_member_use_from_same_package
       typeParameter.name.staticElement = element;
       _define(element);

pkg/analyzer/lib/src/dart/resolver/scope.dart

@@ -27,10 +27,10 @@ class BlockScope {
         NodeList<VariableDeclaration> variables = statement.variables.variables;
         int variableCount = variables.length;
         for (int j = 0; j < variableCount; j++) {
-          yield variables[j].declaredElement!;
+          yield variables[j].declaredElement2!;
         }
       } else if (statement is FunctionDeclarationStatement) {
-        yield statement.functionDeclaration.declaredElement!;
+        yield statement.functionDeclaration.declaredElement2!;
       }
     }
   }

pkg/analyzer/lib/src/dart/resolver/variable_declaration_resolver.dart

@@ -39,7 +39,7 @@ class VariableDeclarationResolver {
       return;
     }
 
-    var element = node.declaredElement!;
+    var element = node.declaredElement2!;
     var isTopLevel =
         element is FieldElement || element is TopLevelVariableElement;
 

pkg/analyzer/lib/src/error/best_practices_verifier.dart

@@ -155,10 +155,11 @@ class BestPracticesVerifier extends RecursiveAstVisitor<void> {
             HintCode.INVALID_IMMUTABLE_ANNOTATION, node, []);
       }
     } else if (element.isInternal) {
-      var parentElement = parent is Declaration ? parent.declaredElement : null;
+      var parentElement =
+          parent is Declaration ? parent.declaredElement2 : null;
       if (parent is TopLevelVariableDeclaration) {
         for (VariableDeclaration variable in parent.variables.variables) {
-          var element = variable.declaredElement as TopLevelVariableElement;
+          var element = variable.declaredElement2 as TopLevelVariableElement;
           if (Identifier.isPrivateName(element.name)) {
             _errorReporter.reportErrorForNode(
                 HintCode.INVALID_INTERNAL_ANNOTATION, variable, []);
@@ -166,14 +167,14 @@ class BestPracticesVerifier extends RecursiveAstVisitor<void> {
         }
       } else if (parent is FieldDeclaration) {
         for (VariableDeclaration variable in parent.fields.variables) {
-          var element = variable.declaredElement as FieldElement;
+          var element = variable.declaredElement2 as FieldElement;
           if (Identifier.isPrivateName(element.name)) {
             _errorReporter.reportErrorForNode(
                 HintCode.INVALID_INTERNAL_ANNOTATION, variable, []);
           }
         }
       } else if (parent is ConstructorDeclaration) {
-        var class_ = parent.declaredElement!.enclosingElement3;
+        var class_ = parent.declaredElement2!.enclosingElement3;
         if (class_.isPrivate || (parentElement?.isPrivate ?? false)) {
           _errorReporter.reportErrorForNode(
               HintCode.INVALID_INTERNAL_ANNOTATION, node, []);
@@ -255,7 +256,7 @@ class BestPracticesVerifier extends RecursiveAstVisitor<void> {
         if (parent is TopLevelVariableDeclaration) {
           for (VariableDeclaration variable in parent.variables.variables) {
             var variableElement =
-                variable.declaredElement as TopLevelVariableElement;
+                variable.declaredElement2 as TopLevelVariableElement;
 
             if (Identifier.isPrivateName(variableElement.name)) {
               reportInvalidAnnotation(variableElement);
@@ -268,7 +269,7 @@ class BestPracticesVerifier extends RecursiveAstVisitor<void> {
           }
         } else if (parent is FieldDeclaration) {
           for (VariableDeclaration variable in parent.fields.variables) {
-            var fieldElement = variable.declaredElement as FieldElement;
+            var fieldElement = variable.declaredElement2 as FieldElement;
             if (parent.isStatic && element.isVisibleForOverriding == true) {
               reportInvalidVisibleForOverriding(fieldElement);
             }
@@ -277,8 +278,8 @@ class BestPracticesVerifier extends RecursiveAstVisitor<void> {
               reportInvalidAnnotation(fieldElement);
             }
           }
-        } else if (parent.declaredElement != null) {
-          final declaredElement = parent.declaredElement!;
+        } else if (parent.declaredElement2 != null) {
+          final declaredElement = parent.declaredElement2!;
           if (element.isVisibleForOverriding &&
               !declaredElement.isInstanceMember) {
             reportInvalidVisibleForOverriding(declaredElement);
@@ -377,7 +378,7 @@ class BestPracticesVerifier extends RecursiveAstVisitor<void> {
 
   @override
   void visitClassDeclaration(ClassDeclaration node) {
-    var element = node.declaredElement as ClassElementImpl;
+    var element = node.declaredElement2 as ClassElementImpl;
     _enclosingClass = element;
     _invalidAccessVerifier._enclosingClass = element;
 
@@ -421,7 +422,7 @@ class BestPracticesVerifier extends RecursiveAstVisitor<void> {
 
   @override
   void visitConstructorDeclaration(ConstructorDeclaration node) {
-    var element = node.declaredElement as ConstructorElementImpl;
+    var element = node.declaredElement2 as ConstructorElementImpl;
     if (!_isNonNullableByDefault && element.isFactory) {
       if (node.body is BlockFunctionBody) {
         // Check the block for a return statement, if not, create the hint.
@@ -470,7 +471,7 @@ class BestPracticesVerifier extends RecursiveAstVisitor<void> {
       super.visitFieldDeclaration(node);
       for (var field in node.fields.variables) {
         ExecutableElement? getOverriddenPropertyAccessor() {
-          final element = field.declaredElement;
+          final element = field.declaredElement2;
           if (element is PropertyAccessorElement || element is FieldElement) {
             Name name = Name(_currentLibrary.source.uri, element!.name);
             Element enclosingElement = element.enclosingElement3!;
@@ -526,7 +527,7 @@ class BestPracticesVerifier extends RecursiveAstVisitor<void> {
   @override
   void visitFunctionDeclaration(FunctionDeclaration node) {
     bool wasInDoNotStoreMember = _inDoNotStoreMember;
-    ExecutableElement element = node.declaredElement!;
+    ExecutableElement element = node.declaredElement2!;
     _deprecatedVerifier.pushInDeprecatedValue(element.hasDeprecated);
     if (element.hasDoNotStore) {
       _inDoNotStoreMember = true;
@@ -641,7 +642,7 @@ class BestPracticesVerifier extends RecursiveAstVisitor<void> {
   @override
   void visitMethodDeclaration(MethodDeclaration node) {
     bool wasInDoNotStoreMember = _inDoNotStoreMember;
-    var element = node.declaredElement!;
+    var element = node.declaredElement2!;
     var enclosingElement = element.enclosingElement3;
 
     Name name = Name(_currentLibrary.source.uri, element.name);
@@ -716,7 +717,7 @@ class BestPracticesVerifier extends RecursiveAstVisitor<void> {
 
   @override
   void visitMixinDeclaration(MixinDeclaration node) {
-    var element = node.declaredElement as ClassElementImpl;
+    var element = node.declaredElement2 as ClassElementImpl;
     _enclosingClass = element;
     _invalidAccessVerifier._enclosingClass = _enclosingClass;
 
@@ -1049,7 +1050,7 @@ class BestPracticesVerifier extends RecursiveAstVisitor<void> {
       return nonFinalFields;
     }
 
-    var element = node.declaredElement as ClassElement;
+    var element = node.declaredElement2 as ClassElement;
     if (isOrInheritsImmutable(element, HashSet<ClassElement>())) {
       Iterable<String> nonFinalFields =
           definedOrInheritedNonFinalInstanceFields(
@@ -1170,7 +1171,7 @@ class BestPracticesVerifier extends RecursiveAstVisitor<void> {
     // ClassElement, but [_checkForInvalidSealedSuperclass] should only be
     // called with a [ClassOrMixinDeclaration], or a [ClassTypeAlias]. The
     // `declaredElement` of these specific classes is a [ClassElement].
-    var element = node.declaredElement as ClassElement;
+    var element = node.declaredElement2 as ClassElement;
     // TODO(srawlins): Perhaps replace this with a getter on Element, like
     // `Element.hasOrInheritsSealed`?
     for (InterfaceType supertype in element.allSupertypes) {
@@ -1451,7 +1452,7 @@ class BestPracticesVerifier extends RecursiveAstVisitor<void> {
         _errorReporter.reportErrorForNode(
           HintCode.RETURN_OF_DO_NOT_STORE,
           entry.key,
-          [entry.value.name!, parent.declaredElement!.displayName],
+          [entry.value.name!, parent.declaredElement2!.displayName],
         );
       }
     }

pkg/analyzer/lib/src/error/deprecated_member_use_verifier.dart

@@ -272,7 +272,7 @@ class DeprecatedMemberUseVerifier {
 
       for (; node != null; node = node.parent) {
         if (node is ConstructorDeclaration) {
-          if (node.declaredElement == definingFunction) {
+          if (node.declaredElement2 == definingFunction) {
             return true;
           }
         } else if (node is FunctionExpression) {
@@ -280,7 +280,7 @@ class DeprecatedMemberUseVerifier {
             return true;
           }
         } else if (node is MethodDeclaration) {
-          if (node.declaredElement == definingFunction) {
+          if (node.declaredElement2 == definingFunction) {
             return true;
           }
         }

pkg/analyzer/lib/src/error/duplicate_definition_verifier.dart

@@ -9,7 +9,6 @@ import 'package:analyzer/dart/ast/token.dart';
 import 'package:analyzer/dart/element/element.dart';
 import 'package:analyzer/error/error.dart';
 import 'package:analyzer/error/listener.dart';
-import 'package:analyzer/src/dart/element/element.dart';
 import 'package:analyzer/src/dart/element/inheritance_manager3.dart';
 import 'package:analyzer/src/diagnostic/diagnostic_factory.dart';
 import 'package:analyzer/src/error/codes.dart';
@@ -46,12 +45,12 @@ class DuplicateDefinitionVerifier {
   }
 
   void checkClass(ClassDeclaration node) {
-    _checkClassMembers(node.declaredElement!, node.members);
+    _checkClassMembers(node.declaredElement2!, node.members);
   }
 
   /// Check that there are no members with the same name.
   void checkEnum(EnumDeclaration node) {
-    var enumElement = node.declaredElement as EnumElementImpl;
+    var enumElement = node.declaredElement2!;
     var enumName = enumElement.name;
 
     var constructorNames = <String>{};
@@ -62,14 +61,14 @@ class DuplicateDefinitionVerifier {
 
     for (EnumConstantDeclaration constant in node.constants) {
       _checkDuplicateIdentifier(staticGetters, constant.name2,
-          element: constant.declaredElement!);
+          element: constant.declaredElement2!);
       _checkValuesDeclarationInEnum(constant.name2);
     }
 
     for (var member in node.members) {
       if (member is ConstructorDeclaration) {
         if (member.returnType.name == enumElement.name) {
-          var name = member.declaredElement!.name;
+          var name = member.declaredElement2!.name;
           if (!constructorNames.add(name)) {
             if (name.isEmpty) {
               _errorReporter.reportErrorForName(
@@ -91,7 +90,7 @@ class DuplicateDefinitionVerifier {
           _checkDuplicateIdentifier(
             member.isStatic ? staticGetters : instanceGetters,
             identifier,
-            element: field.declaredElement!,
+            element: field.declaredElement2!,
             setterScope: member.isStatic ? staticSetters : instanceSetters,
           );
           _checkValuesDeclarationInEnum(identifier);
@@ -100,7 +99,7 @@ class DuplicateDefinitionVerifier {
         _checkDuplicateIdentifier(
           member.isStatic ? staticGetters : instanceGetters,
           member.name2,
-          element: member.declaredElement!,
+          element: member.declaredElement2!,
           setterScope: member.isStatic ? staticSetters : instanceSetters,
         );
         if (!(member.isStatic && member.isSetter)) {
@@ -126,7 +125,7 @@ class DuplicateDefinitionVerifier {
     }
 
     _checkConflictingConstructorAndStatic(
-      classElement: enumElement,
+      interfaceElement: enumElement,
       staticGetters: staticGetters,
       staticSetters: staticSetters,
     );
@@ -200,7 +199,7 @@ class DuplicateDefinitionVerifier {
           _checkDuplicateIdentifier(
             member.isStatic ? staticGetters : instanceGetters,
             identifier,
-            element: field.declaredElement!,
+            element: field.declaredElement2!,
             setterScope: member.isStatic ? staticSetters : instanceSetters,
           );
         }
@@ -208,7 +207,7 @@ class DuplicateDefinitionVerifier {
         _checkDuplicateIdentifier(
           member.isStatic ? staticGetters : instanceGetters,
           member.name2,
-          element: member.declaredElement!,
+          element: member.declaredElement2!,
           setterScope: member.isStatic ? staticSetters : instanceSetters,
         );
       }
@@ -254,12 +253,12 @@ class DuplicateDefinitionVerifier {
     Map<String, Element> definedNames = HashMap<String, Element>();
     for (VariableDeclaration variable in node.variables) {
       _checkDuplicateIdentifier(definedNames, variable.name2,
-          element: variable.declaredElement!);
+          element: variable.declaredElement2!);
     }
   }
 
   void checkMixin(MixinDeclaration node) {
-    _checkClassMembers(node.declaredElement!, node.members);
+    _checkClassMembers(node.declaredElement2!, node.members);
   }
 
   /// Check that all of the parameters have unique names.
@@ -283,13 +282,13 @@ class DuplicateDefinitionVerifier {
       if (statement is VariableDeclarationStatement) {
         for (VariableDeclaration variable in statement.variables.variables) {
           _checkDuplicateIdentifier(definedNames, variable.name2,
-              element: variable.declaredElement!);
+              element: variable.declaredElement2!);
         }
       } else if (statement is FunctionDeclarationStatement) {
         _checkDuplicateIdentifier(
           definedNames,
           statement.functionDeclaration.name2,
-          element: statement.functionDeclaration.declaredElement!,
+          element: statement.functionDeclaration.declaredElement2!,
         );
       }
     }
@@ -300,7 +299,7 @@ class DuplicateDefinitionVerifier {
     Map<String, Element> definedNames = HashMap<String, Element>();
     for (TypeParameter parameter in node.typeParameters) {
       _checkDuplicateIdentifier(definedNames, parameter.name2,
-          element: parameter.declaredElement!);
+          element: parameter.declaredElement2!);
     }
   }
 
@@ -358,22 +357,22 @@ class DuplicateDefinitionVerifier {
         var identifier = member.name2;
         if (identifier != null) {
           _checkDuplicateIdentifier(definedGetters, identifier,
-              element: member.declaredElement!, setterScope: definedSetters);
+              element: member.declaredElement2!, setterScope: definedSetters);
         }
       } else if (member is NamedCompilationUnitMember) {
         _checkDuplicateIdentifier(definedGetters, member.name2,
-            element: member.declaredElement!, setterScope: definedSetters);
+            element: member.declaredElement2!, setterScope: definedSetters);
       } else if (member is TopLevelVariableDeclaration) {
         for (VariableDeclaration variable in member.variables.variables) {
           _checkDuplicateIdentifier(definedGetters, variable.name2,
-              element: variable.declaredElement!, setterScope: definedSetters);
+              element: variable.declaredElement2!, setterScope: definedSetters);
         }
       }
     }
   }
 
   /// Check that there are no members with the same name.
-  void _checkClassMembers(ClassElement element, List<ClassMember> members) {
+  void _checkClassMembers(InterfaceElement element, List<ClassMember> members) {
     var constructorNames = HashSet<String>();
     var instanceGetters = HashMap<String, Element>();
     var instanceSetters = HashMap<String, Element>();
@@ -405,7 +404,7 @@ class DuplicateDefinitionVerifier {
           _checkDuplicateIdentifier(
             member.isStatic ? staticGetters : instanceGetters,
             field.name2,
-            element: field.declaredElement!,
+            element: field.declaredElement2!,
             setterScope: member.isStatic ? staticSetters : instanceSetters,
           );
         }
@@ -413,14 +412,14 @@ class DuplicateDefinitionVerifier {
         _checkDuplicateIdentifier(
           member.isStatic ? staticGetters : instanceGetters,
           member.name2,
-          element: member.declaredElement!,
+          element: member.declaredElement2!,
           setterScope: member.isStatic ? staticSetters : instanceSetters,
         );
       }
     }
 
     _checkConflictingConstructorAndStatic(
-      classElement: element,
+      interfaceElement: element,
       staticGetters: staticGetters,
       staticSetters: staticSetters,
     );
@@ -462,11 +461,11 @@ class DuplicateDefinitionVerifier {
   }
 
   void _checkConflictingConstructorAndStatic({
-    required ClassElement classElement,
+    required InterfaceElement interfaceElement,
     required Map<String, Element> staticGetters,
     required Map<String, Element> staticSetters,
   }) {
-    for (var constructor in classElement.constructors) {
+    for (var constructor in interfaceElement.constructors) {
       var name = constructor.name;
       var staticMember = staticGetters[name] ?? staticSetters[name];
       if (staticMember is PropertyAccessorElement) {
@@ -578,7 +577,7 @@ class DuplicateDefinitionVerifier {
   }
 
   ExecutableElement? _getInheritedMember(
-      ClassElement element, String baseName) {
+      InterfaceElement element, String baseName) {
     var libraryUri = _currentLibrary.source.uri;
 
     var getterName = Name(libraryUri, baseName);
@@ -592,7 +591,7 @@ class DuplicateDefinitionVerifier {
   }
 
   ExecutableElement? _getInterfaceMember(
-      ClassElement element, String baseName) {
+      InterfaceElement element, String baseName) {
     var libraryUri = _currentLibrary.source.uri;
 
     var getterName = Name(libraryUri, baseName);

pkg/analyzer/lib/src/error/getter_setter_types_verifier.dart

@@ -39,8 +39,8 @@ class GetterSetterTypesVerifier {
     }
   }
 
-  void checkInterface(ClassElement classElement, Interface interface) {
-    var libraryUri = classElement.library.source.uri;
+  void checkInterface(InterfaceElement element, Interface interface) {
+    var libraryUri = element.library.source.uri;
 
     for (var name in interface.map.keys) {
       if (!name.isAccessibleFor(libraryUri)) continue;
@@ -53,22 +53,22 @@ class GetterSetterTypesVerifier {
           var setterType = setter.parameters[0].type;
           if (!_match(getterType, setterType)) {
             Element errorElement;
-            if (getter.enclosingElement3 == classElement) {
+            if (getter.enclosingElement3 == element) {
               errorElement = getter;
-            } else if (setter.enclosingElement3 == classElement) {
+            } else if (setter.enclosingElement3 == element) {
               errorElement = setter;
             } else {
-              errorElement = classElement;
+              errorElement = element;
             }
 
             var getterName = getter.displayName;
-            if (getter.enclosingElement3 != classElement) {
+            if (getter.enclosingElement3 != element) {
               var getterClassName = getter.enclosingElement3.displayName;
               getterName = '$getterClassName.$getterName';
             }
 
             var setterName = setter.displayName;
-            if (setter.enclosingElement3 != classElement) {
+            if (setter.enclosingElement3 != element) {
               var setterClassName = setter.enclosingElement3.displayName;
               setterName = '$setterClassName.$setterName';
             }

pkg/analyzer/lib/src/error/inheritance_override.dart

@@ -46,7 +46,7 @@ class InheritanceOverrideVerifier {
           featureSet: unit.featureSet,
           library: library,
           classNameToken: declaration.name2,
-          classElement: declaration.declaredElement as AbstractClassElementImpl,
+          classElement: declaration.declaredElement2!,
           implementsClause: declaration.implementsClause,
           members: declaration.members,
           superclass: declaration.extendsClause?.superclass,
@@ -61,7 +61,7 @@ class InheritanceOverrideVerifier {
           featureSet: unit.featureSet,
           library: library,
           classNameToken: declaration.name2,
-          classElement: declaration.declaredElement as AbstractClassElementImpl,
+          classElement: declaration.declaredElement2!,
           implementsClause: declaration.implementsClause,
           superclass: declaration.superclass,
           withClause: declaration.withClause,
@@ -75,7 +75,7 @@ class InheritanceOverrideVerifier {
           featureSet: unit.featureSet,
           library: library,
           classNameToken: declaration.name2,
-          classElement: declaration.declaredElement as AbstractClassElementImpl,
+          classElement: declaration.declaredElement2!,
           implementsClause: declaration.implementsClause,
           members: declaration.members,
           withClause: declaration.withClause,
@@ -89,7 +89,7 @@ class InheritanceOverrideVerifier {
           featureSet: unit.featureSet,
           library: library,
           classNameToken: declaration.name2,
-          classElement: declaration.declaredElement as AbstractClassElementImpl,
+          classElement: declaration.declaredElement2!,
           implementsClause: declaration.implementsClause,
           members: declaration.members,
           onClause: declaration.onClause,
@@ -122,7 +122,7 @@ class _ClassVerifier {
   final FeatureSet featureSet;
   final LibraryElementImpl library;
   final Uri libraryUri;
-  final AbstractClassElementImpl classElement;
+  final InterfaceElement classElement;
 
   final Token classNameToken;
   final List<ClassMember> members;
@@ -161,7 +161,9 @@ class _ClassVerifier {
       return true;
     }
 
+    final classElement = this.classElement;
     if (classElement is! EnumElement &&
+        classElement is ClassElement &&
         !classElement.isAbstract &&
         implementsDartCoreEnum) {
       reporter.reportErrorForToken(
@@ -186,7 +188,9 @@ class _ClassVerifier {
     if (classElement.supertype != null) {
       directSuperInterfaces.add(classElement.supertype!);
     }
-    directSuperInterfaces.addAll(classElement.superclassConstraints);
+    if (classElement is MixinElement) {
+      directSuperInterfaces.addAll(classElement.superclassConstraints);
+    }
 
     // Each mixin in `class C extends S with M0, M1, M2 {}` is equivalent to:
     //   class S&M0 extends S { ...members of M0... }
@@ -211,7 +215,7 @@ class _ClassVerifier {
       if (member is FieldDeclaration) {
         var fieldList = member.fields;
         for (var field in fieldList.variables) {
-          var fieldElement = field.declaredElement as FieldElement;
+          var fieldElement = field.declaredElement2 as FieldElement;
           _checkDeclaredMember(field.name2, libraryUri, fieldElement.getter);
           _checkDeclaredMember(field.name2, libraryUri, fieldElement.setter);
           if (!member.isStatic && classElement is! EnumElement) {
@@ -227,7 +231,7 @@ class _ClassVerifier {
           continue;
         }
 
-        _checkDeclaredMember(member.name2, libraryUri, member.declaredElement,
+        _checkDeclaredMember(member.name2, libraryUri, member.declaredElement2,
             methodParameterNodes: member.parameters?.parameters);
         if (!(member.isStatic || member.isAbstract || member.isSetter)) {
           _checkIllegalConcreteEnumMemberDeclaration(member.name2);
@@ -246,7 +250,7 @@ class _ClassVerifier {
       errorReporter: reporter,
     ).checkInterface(classElement, interface);
 
-    if (!classElement.isAbstract) {
+    if (!(classElement as ClassElement).isAbstract) {
       List<ExecutableElement>? inheritedAbstract;
 
       for (var name in interface.map.keys) {
@@ -402,12 +406,14 @@ class _ClassVerifier {
       return false;
     }
 
-    var interfaceElement = type.element2;
+    final typeElement = type.element2;
 
-    if (interfaceElement is ClassElement &&
-        interfaceElement.isDartCoreEnum &&
+    final classElement = this.classElement;
+    if (typeElement is ClassElement &&
+        typeElement.isDartCoreEnum &&
         library.featureSet.isEnabled(Feature.enhanced_enums)) {
-      if (classElement.isAbstract || classElement is EnumElement) {
+      if (classElement is ClassElement && classElement.isAbstract ||
+          classElement is EnumElement) {
         return false;
       }
       reporter.reportErrorForNode(
@@ -417,7 +423,7 @@ class _ClassVerifier {
       return true;
     }
 
-    if (typeProvider.isNonSubtypableClass(interfaceElement)) {
+    if (typeProvider.isNonSubtypableClass(typeElement)) {
       reporter.reportErrorForNode(errorCode, namedType, [type]);
       return true;
     }
@@ -671,14 +677,19 @@ class _ClassVerifier {
   }
 
   void _checkIllegalConcreteEnumMemberDeclaration(Token name) {
-    if (implementsDartCoreEnum &&
-        !classElement.isDartCoreEnumImpl &&
-        const {'index', 'hashCode', '=='}.contains(name.lexeme)) {
-      reporter.reportErrorForToken(
-        CompileTimeErrorCode.ILLEGAL_CONCRETE_ENUM_MEMBER_DECLARATION,
-        name,
-        [name.lexeme],
-      );
+    if (implementsDartCoreEnum) {
+      final classElement = this.classElement;
+      if (classElement is ClassElementImpl &&
+              !classElement.isDartCoreEnumImpl ||
+          classElement is EnumElementImpl) {
+        if (const {'index', 'hashCode', '=='}.contains(name.lexeme)) {
+          reporter.reportErrorForToken(
+            CompileTimeErrorCode.ILLEGAL_CONCRETE_ENUM_MEMBER_DECLARATION,
+            name,
+            [name.lexeme],
+          );
+        }
+      }
     }
   }
 
@@ -918,7 +929,7 @@ class _ClassVerifier {
   }
 
   bool _reportNoCombinedSuperSignature(MethodDeclaration node) {
-    var element = node.declaredElement;
+    var element = node.declaredElement2;
     if (element is MethodElementImpl) {
       var inferenceError = element.typeInferenceError;
       if (inferenceError?.kind ==

pkg/analyzer/lib/src/error/must_call_super_verifier.dart

@@ -20,7 +20,7 @@ class MustCallSuperVerifier {
     if (node.isStatic || node.isAbstract) {
       return;
     }
-    var element = node.declaredElement!;
+    var element = node.declaredElement2!;
     var overridden = _findOverriddenMemberWithMustCallSuper(element);
     if (overridden == null) {
       return;
@@ -136,7 +136,7 @@ class MustCallSuperVerifier {
 
   void _verifySuperIsCalled(MethodDeclaration node, String methodName,
       String? overriddenEnclosingName) {
-    var declaredElement = node.declaredElement as ExecutableElementImpl;
+    var declaredElement = node.declaredElement2 as ExecutableElementImpl;
     if (!declaredElement.invokesSuperSelf) {
       // Overridable elements are always enclosed in named elements, so it is
       // safe to assume [overriddenEnclosingName] is non-`null`.

pkg/analyzer/lib/src/error/override_verifier.dart

@@ -23,7 +23,7 @@ class OverrideVerifier extends RecursiveAstVisitor<void> {
   final ErrorReporter _errorReporter;
 
   /// The current class or mixin.
-  ClassElement? _currentClass;
+  InterfaceElement? _currentClass;
 
   OverrideVerifier(
       this._inheritance, LibraryElement library, this._errorReporter)
@@ -31,14 +31,14 @@ class OverrideVerifier extends RecursiveAstVisitor<void> {
 
   @override
   void visitClassDeclaration(ClassDeclaration node) {
-    _currentClass = node.declaredElement;
+    _currentClass = node.declaredElement2;
     super.visitClassDeclaration(node);
     _currentClass = null;
   }
 
   @override
   void visitEnumDeclaration(EnumDeclaration node) {
-    _currentClass = node.declaredElement;
+    _currentClass = node.declaredElement2;
     super.visitEnumDeclaration(node);
     _currentClass = null;
   }
@@ -46,7 +46,7 @@ class OverrideVerifier extends RecursiveAstVisitor<void> {
   @override
   void visitFieldDeclaration(FieldDeclaration node) {
     for (VariableDeclaration field in node.fields.variables) {
-      var fieldElement = field.declaredElement as FieldElement;
+      var fieldElement = field.declaredElement2 as FieldElement;
       if (fieldElement.hasOverride) {
         var getter = fieldElement.getter;
         if (getter != null && _isOverride(getter)) continue;
@@ -64,7 +64,7 @@ class OverrideVerifier extends RecursiveAstVisitor<void> {
 
   @override
   void visitMethodDeclaration(MethodDeclaration node) {
-    var element = node.declaredElement!;
+    var element = node.declaredElement2!;
     if (element.hasOverride && !_isOverride(element)) {
       if (element is MethodElement) {
         _errorReporter.reportErrorForToken(
@@ -89,7 +89,7 @@ class OverrideVerifier extends RecursiveAstVisitor<void> {
 
   @override
   void visitMixinDeclaration(MixinDeclaration node) {
-    _currentClass = node.declaredElement;
+    _currentClass = node.declaredElement2;
     super.visitMixinDeclaration(node);
     _currentClass = null;
   }

pkg/analyzer/lib/src/error/unused_local_elements_verifier.dart

@@ -72,7 +72,7 @@ class GatherUsedLocalElementsVisitor extends RecursiveAstVisitor<void> {
   void visitClassDeclaration(ClassDeclaration node) {
     var enclosingClassOld = _enclosingClass;
     try {
-      _enclosingClass = node.declaredElement;
+      _enclosingClass = node.declaredElement2;
       super.visitClassDeclaration(node);
     } finally {
       _enclosingClass = enclosingClassOld;
@@ -81,7 +81,7 @@ class GatherUsedLocalElementsVisitor extends RecursiveAstVisitor<void> {
 
   @override
   void visitConstructorDeclaration(ConstructorDeclaration node) {
-    var element = node.declaredElement!;
+    var element = node.declaredElement2!;
     var redirectedConstructor = node.redirectedConstructor;
     if (redirectedConstructor != null) {
       var redirectedElement = redirectedConstructor.staticElement;
@@ -126,7 +126,7 @@ class GatherUsedLocalElementsVisitor extends RecursiveAstVisitor<void> {
   void visitFunctionDeclaration(FunctionDeclaration node) {
     var enclosingExecOld = _enclosingExec;
     try {
-      _enclosingExec = node.declaredElement;
+      _enclosingExec = node.declaredElement2;
       super.visitFunctionDeclaration(node);
     } finally {
       _enclosingExec = enclosingExecOld;
@@ -176,7 +176,7 @@ class GatherUsedLocalElementsVisitor extends RecursiveAstVisitor<void> {
   void visitMethodDeclaration(MethodDeclaration node) {
     var enclosingExecOld = _enclosingExec;
     try {
-      _enclosingExec = node.declaredElement;
+      _enclosingExec = node.declaredElement2;
       super.visitMethodDeclaration(node);
     } finally {
       _enclosingExec = enclosingExecOld;
@@ -456,7 +456,7 @@ class UnusedLocalElementsVerifier extends RecursiveAstVisitor<void> {
 
   @override
   void visitClassDeclaration(ClassDeclaration node) {
-    final declaredElement = node.declaredElement as ClassElement;
+    final declaredElement = node.declaredElement2!;
     _visitClassElement(declaredElement);
 
     super.visitClassDeclaration(node);
@@ -465,7 +465,7 @@ class UnusedLocalElementsVerifier extends RecursiveAstVisitor<void> {
   @override
   void visitConstructorDeclaration(ConstructorDeclaration node) {
     if (node.name2 != null) {
-      final declaredElement = node.declaredElement as ConstructorElement;
+      final declaredElement = node.declaredElement2!;
       _visitConstructorElement(declaredElement);
     }
 
@@ -474,7 +474,7 @@ class UnusedLocalElementsVerifier extends RecursiveAstVisitor<void> {
 
   @override
   void visitEnumConstantDeclaration(EnumConstantDeclaration node) {
-    final declaredElement = node.declaredElement as FieldElement;
+    final declaredElement = node.declaredElement2 as FieldElement;
     _visitFieldElement(declaredElement);
 
     super.visitEnumConstantDeclaration(node);
@@ -482,7 +482,7 @@ class UnusedLocalElementsVerifier extends RecursiveAstVisitor<void> {
 
   @override
   void visitEnumDeclaration(EnumDeclaration node) {
-    final declaredElement = node.declaredElement as ClassElement;
+    final declaredElement = node.declaredElement2!;
     _visitClassElement(declaredElement);
 
     super.visitEnumDeclaration(node);
@@ -501,7 +501,7 @@ class UnusedLocalElementsVerifier extends RecursiveAstVisitor<void> {
 
   @override
   void visitFunctionDeclaration(FunctionDeclaration node) {
-    final declaredElement = node.declaredElement;
+    final declaredElement = node.declaredElement2;
     if (declaredElement is FunctionElement) {
       _visitFunctionElement(declaredElement);
     } else if (declaredElement is PropertyAccessorElement) {
@@ -513,7 +513,7 @@ class UnusedLocalElementsVerifier extends RecursiveAstVisitor<void> {
 
   @override
   void visitFunctionTypeAlias(FunctionTypeAlias node) {
-    final declaredElement = node.declaredElement as TypeAliasElement;
+    final declaredElement = node.declaredElement2!;
     _visitTypeAliasElement(declaredElement);
 
     super.visitFunctionTypeAlias(node);
@@ -521,7 +521,7 @@ class UnusedLocalElementsVerifier extends RecursiveAstVisitor<void> {
 
   @override
   void visitGenericTypeAlias(GenericTypeAlias node) {
-    final declaredElement = node.declaredElement as TypeAliasElement;
+    final declaredElement = node.declaredElement2 as TypeAliasElement;
     _visitTypeAliasElement(declaredElement);
 
     super.visitGenericTypeAlias(node);
@@ -529,7 +529,7 @@ class UnusedLocalElementsVerifier extends RecursiveAstVisitor<void> {
 
   @override
   void visitMethodDeclaration(MethodDeclaration node) {
-    final declaredElement = node.declaredElement;
+    final declaredElement = node.declaredElement2;
     if (declaredElement is MethodElement) {
       _visitMethodElement(declaredElement);
     } else if (declaredElement is PropertyAccessorElement) {
@@ -541,7 +541,7 @@ class UnusedLocalElementsVerifier extends RecursiveAstVisitor<void> {
 
   @override
   void visitMixinDeclaration(MixinDeclaration node) {
-    final declaredElement = node.declaredElement as ClassElement;
+    final declaredElement = node.declaredElement2!;
     _visitClassElement(declaredElement);
 
     super.visitMixinDeclaration(node);
@@ -797,7 +797,7 @@ class UnusedLocalElementsVerifier extends RecursiveAstVisitor<void> {
     }
   }
 
-  void _visitClassElement(ClassElement element) {
+  void _visitClassElement(InterfaceElement element) {
     if (!_isUsedElement(element)) {
       _reportErrorForElement(
           HintCode.UNUSED_ELEMENT, element, [element.displayName]);

pkg/analyzer/lib/src/generated/element_resolver.dart

@@ -128,7 +128,7 @@ class ElementResolver {
   }
 
   void visitConstructorDeclaration(ConstructorDeclaration node) {
-    ConstructorElement element = node.declaredElement!;
+    ConstructorElement element = node.declaredElement2!;
     if (element is ConstructorElementImpl) {
       var redirectedNode = node.redirectedConstructor;
       if (redirectedNode != null) {

pkg/analyzer/lib/src/generated/error_verifier.dart

@@ -202,7 +202,7 @@ class ErrorVerifier extends RecursiveAstVisitor<void>
 
   /// The class containing the AST nodes being visited, or `null` if we are not
   /// in the scope of a class.
-  ClassElement? _enclosingClass;
+  InterfaceElement? _enclosingClass;
 
   /// The element of the extension being visited, or `null` if we are not
   /// in the scope of an extension.
@@ -267,7 +267,7 @@ class ErrorVerifier extends RecursiveAstVisitor<void>
     );
   }
 
-  ClassElement? get enclosingClass => _enclosingClass;
+  InterfaceElement? get enclosingClass => _enclosingClass;
 
   /// For consumers of error verification as a library, (currently just the
   /// angular plugin), expose a setter that can make the errors reported more
@@ -275,7 +275,7 @@ class ErrorVerifier extends RecursiveAstVisitor<void>
   /// context. Note that this setter is very defensive for potential misuse; it
   /// should not be modified in the middle of visiting a tree and requires an
   /// analyzer-provided Impl instance to work.
-  set enclosingClass(ClassElement? classElement) {
+  set enclosingClass(InterfaceElement? interfaceElement) {
     assert(_enclosingClass == null);
     assert(_enclosingExecutable.element == null);
   }
@@ -421,7 +421,7 @@ class ErrorVerifier extends RecursiveAstVisitor<void>
   void visitClassDeclaration(ClassDeclaration node) {
     var outerClass = _enclosingClass;
     try {
-      var element = node.declaredElement as ClassElementImpl;
+      var element = node.declaredElement2 as ClassElementImpl;
       _isInNativeClass = node.nativeClause != null;
       _enclosingClass = element;
 
@@ -448,7 +448,7 @@ class ErrorVerifier extends RecursiveAstVisitor<void>
       _checkForFinalNotInitializedInClass(members);
       _checkForBadFunctionUse(node);
       _checkForWrongTypeParameterVarianceInSuperinterfaces();
-      _checkForMainFunction1(node.name2, node.declaredElement!);
+      _checkForMainFunction1(node.name2, node.declaredElement2!);
       _reportMacroApplicationErrors(
         annotations: node.metadata,
         macroErrors: element.macroApplicationErrors,
@@ -473,10 +473,10 @@ class ErrorVerifier extends RecursiveAstVisitor<void>
         node.name2, CompileTimeErrorCode.BUILT_IN_IDENTIFIER_AS_TYPEDEF_NAME);
     var outerClassElement = _enclosingClass;
     try {
-      _enclosingClass = node.declaredElement as ClassElementImpl;
+      _enclosingClass = node.declaredElement2 as ClassElementImpl;
       _checkClassInheritance(
           node, node.superclass, node.withClause, node.implementsClause);
-      _checkForMainFunction1(node.name2, node.declaredElement!);
+      _checkForMainFunction1(node.name2, node.declaredElement2!);
       _checkForWrongTypeParameterVarianceInSuperinterfaces();
     } finally {
       _enclosingClass = outerClassElement;
@@ -513,7 +513,7 @@ class ErrorVerifier extends RecursiveAstVisitor<void>
 
   @override
   void visitConstructorDeclaration(ConstructorDeclaration node) {
-    var element = node.declaredElement!;
+    var element = node.declaredElement2!;
     _withEnclosingExecutable(element, () {
       _checkForNonConstGenerativeEnumConstructor(node);
       _checkForInvalidModifierOnBody(
@@ -596,7 +596,7 @@ class ErrorVerifier extends RecursiveAstVisitor<void>
   void visitEnumDeclaration(EnumDeclaration node) {
     var outerClass = _enclosingClass;
     try {
-      var element = node.declaredElement as EnumElementImpl;
+      var element = node.declaredElement2 as EnumElementImpl;
       _enclosingClass = element;
       _duplicateDefinitionVerifier.checkEnum(node);
 
@@ -613,7 +613,7 @@ class ErrorVerifier extends RecursiveAstVisitor<void>
       _constructorFieldsVerifier.enterEnum(node, element);
       _checkForFinalNotInitializedInClass(node.members);
       _checkForWrongTypeParameterVarianceInSuperinterfaces();
-      _checkForMainFunction1(node.name2, node.declaredElement!);
+      _checkForMainFunction1(node.name2, node.declaredElement2!);
       _checkForEnumInstantiatedToBoundsIsNotWellBounded(node, element);
 
       GetterSetterTypesVerifier(
@@ -653,7 +653,7 @@ class ErrorVerifier extends RecursiveAstVisitor<void>
 
   @override
   void visitExtensionDeclaration(ExtensionDeclaration node) {
-    var element = node.declaredElement!;
+    var element = node.declaredElement2!;
     _enclosingExtension = element;
     _duplicateDefinitionVerifier.checkExtension(node);
     _checkForConflictingExtensionTypeVariableErrorCodes();
@@ -719,7 +719,7 @@ class ErrorVerifier extends RecursiveAstVisitor<void>
   @override
   void visitForEachPartsWithDeclaration(ForEachPartsWithDeclaration node) {
     DeclaredIdentifier loopVariable = node.loopVariable;
-    if (_checkForEachParts(node, loopVariable.declaredElement)) {
+    if (_checkForEachParts(node, loopVariable.declaredElement2)) {
       if (loopVariable.isConst) {
         errorReporter.reportErrorForToken(
             CompileTimeErrorCode.FOR_IN_WITH_CONST_VARIABLE,
@@ -754,7 +754,7 @@ class ErrorVerifier extends RecursiveAstVisitor<void>
 
   @override
   void visitFunctionDeclaration(FunctionDeclaration node) {
-    ExecutableElement functionElement = node.declaredElement!;
+    ExecutableElement functionElement = node.declaredElement2!;
     if (functionElement.enclosingElement3 is! CompilationUnitElement) {
       _hiddenElements!.declare(functionElement);
     }
@@ -769,8 +769,8 @@ class ErrorVerifier extends RecursiveAstVisitor<void>
       }
       _checkForTypeAnnotationDeferredClass(returnType);
       _returnTypeVerifier.verifyReturnType(returnType);
-      _checkForImplicitDynamicReturn(node.name2, node.declaredElement!);
-      _checkForMainFunction1(node.name2, node.declaredElement!);
+      _checkForImplicitDynamicReturn(node.name2, node.declaredElement2!);
+      _checkForMainFunction1(node.name2, node.declaredElement2!);
       _checkForMainFunction2(node);
       super.visitFunctionDeclaration(node);
     });
@@ -817,9 +817,9 @@ class ErrorVerifier extends RecursiveAstVisitor<void>
   void visitFunctionTypeAlias(FunctionTypeAlias node) {
     _checkForBuiltInIdentifierAsName(
         node.name2, CompileTimeErrorCode.BUILT_IN_IDENTIFIER_AS_TYPEDEF_NAME);
-    _checkForMainFunction1(node.name2, node.declaredElement!);
+    _checkForMainFunction1(node.name2, node.declaredElement2!);
     _checkForTypeAliasCannotReferenceItself(
-        node.name2, node.declaredElement as TypeAliasElementImpl);
+        node.name2, node.declaredElement2 as TypeAliasElementImpl);
     super.visitFunctionTypeAlias(node);
   }
 
@@ -854,9 +854,9 @@ class ErrorVerifier extends RecursiveAstVisitor<void>
   void visitGenericTypeAlias(GenericTypeAlias node) {
     _checkForBuiltInIdentifierAsName(
         node.name2, CompileTimeErrorCode.BUILT_IN_IDENTIFIER_AS_TYPEDEF_NAME);
-    _checkForMainFunction1(node.name2, node.declaredElement!);
+    _checkForMainFunction1(node.name2, node.declaredElement2!);
     _checkForTypeAliasCannotReferenceItself(
-        node.name2, node.declaredElement as TypeAliasElementImpl);
+        node.name2, node.declaredElement2 as TypeAliasElementImpl);
     super.visitGenericTypeAlias(node);
   }
 
@@ -947,7 +947,7 @@ class ErrorVerifier extends RecursiveAstVisitor<void>
 
   @override
   void visitMethodDeclaration(MethodDeclaration node) {
-    _withEnclosingExecutable(node.declaredElement!, () {
+    _withEnclosingExecutable(node.declaredElement2!, () {
       var returnType = node.returnType;
       if (node.isSetter) {
         _checkForWrongNumberOfParametersForSetter(node.name2, node.parameters);
@@ -965,7 +965,7 @@ class ErrorVerifier extends RecursiveAstVisitor<void>
       _checkForExtensionDeclaresMemberOfObject(node);
       _checkForTypeAnnotationDeferredClass(returnType);
       _returnTypeVerifier.verifyReturnType(returnType);
-      _checkForImplicitDynamicReturn(node.name2, node.declaredElement!);
+      _checkForImplicitDynamicReturn(node.name2, node.declaredElement2!);
       _checkForWrongTypeParameterVarianceInMethod(node);
       super.visitMethodDeclaration(node);
     });
@@ -995,7 +995,7 @@ class ErrorVerifier extends RecursiveAstVisitor<void>
     // TODO(scheglov) Verify for all mixin errors.
     var outerClass = _enclosingClass;
     try {
-      _enclosingClass = node.declaredElement as ClassElementImpl;
+      _enclosingClass = node.declaredElement2!;
 
       List<ClassMember> members = node.members;
       _duplicateDefinitionVerifier.checkMixin(node);
@@ -1013,7 +1013,7 @@ class ErrorVerifier extends RecursiveAstVisitor<void>
 
       _checkForConflictingClassMembers();
       _checkForFinalNotInitializedInClass(members);
-      _checkForMainFunction1(node.name2, node.declaredElement!);
+      _checkForMainFunction1(node.name2, node.declaredElement2!);
       _checkForWrongTypeParameterVarianceInSuperinterfaces();
       //      _checkForBadFunctionUse(node);
       super.visitMixinDeclaration(node);
@@ -1274,7 +1274,7 @@ class ErrorVerifier extends RecursiveAstVisitor<void>
     _checkForNotInitializedNonNullableVariable(node.variables, true);
 
     for (var variable in node.variables.variables) {
-      _checkForMainFunction1(variable.name2, variable.declaredElement!);
+      _checkForMainFunction1(variable.name2, variable.declaredElement2!);
     }
 
     super.visitTopLevelVariableDeclaration(node);
@@ -1313,7 +1313,7 @@ class ErrorVerifier extends RecursiveAstVisitor<void>
     var initializerNode = node.initializer;
     // do checks
     _checkForImplicitDynamicIdentifier(node, nameToken,
-        variable: node.declaredElement!);
+        variable: node.declaredElement2!);
     _checkForAbstractOrExternalVariableInitializer(node);
     // visit initializer
     String name = nameToken.lexeme;
@@ -1329,7 +1329,7 @@ class ErrorVerifier extends RecursiveAstVisitor<void>
     AstNode grandparent = node.parent!.parent!;
     if (grandparent is! TopLevelVariableDeclaration &&
         grandparent is! FieldDeclaration) {
-      VariableElement element = node.declaredElement!;
+      VariableElement element = node.declaredElement2!;
       // There is no hidden elements if we are outside of a function body,
       // which will happen for variables declared in control flow elements.
       _hiddenElements?.declare(element);
@@ -1419,7 +1419,7 @@ class ErrorVerifier extends RecursiveAstVisitor<void>
 
   void _checkForAbstractOrExternalVariableInitializer(
       VariableDeclaration node) {
-    var declaredElement = node.declaredElement;
+    var declaredElement = node.declaredElement2;
     if (node.initializer != null) {
       if (declaredElement is FieldElement) {
         if (declaredElement.isAbstract) {
@@ -1521,7 +1521,7 @@ class ErrorVerifier extends RecursiveAstVisitor<void>
     DartType redirectedReturnType = redirectedType.returnType;
 
     // Report specific problem when return type is incompatible
-    FunctionType constructorType = declaration.declaredElement!.type;
+    FunctionType constructorType = declaration.declaredElement2!.type;
     DartType constructorReturnType = constructorType.returnType;
     if (!typeSystem.isAssignableTo(
         redirectedReturnType, constructorReturnType)) {
@@ -1926,7 +1926,7 @@ class ErrorVerifier extends RecursiveAstVisitor<void>
   }
 
   void _checkForConflictingGenerics(NamedCompilationUnitMember node) {
-    var element = node.declaredElement as ClassElement;
+    var element = node.declaredElement2 as InterfaceElement;
 
     var analysisSession = _currentLibrary.session;
     var errors = analysisSession.classHierarchy.errors(element);
@@ -1993,7 +1993,7 @@ class ErrorVerifier extends RecursiveAstVisitor<void>
         // [declaration] is a redirecting constructor via a redirecting
         // initializer.
         _checkForRedirectToNonConstConstructor(
-          declaration.declaredElement!,
+          declaration.declaredElement2!,
           initializer.staticElement,
           initializer.constructorName ?? initializer.thisKeyword,
         );
@@ -2721,7 +2721,7 @@ class ErrorVerifier extends RecursiveAstVisitor<void>
               variable.name2,
               [variable.name2.lexeme]);
         } else {
-          var variableElement = variable.declaredElement;
+          var variableElement = variable.declaredElement2;
           if (variableElement is FieldElement &&
               (variableElement.isAbstract || variableElement.isExternal)) {
             // Abstract and external fields can't be initialized, so no error.
@@ -3805,7 +3805,7 @@ class ErrorVerifier extends RecursiveAstVisitor<void>
     if (_isEnclosingClassFfiUnion) return;
 
     for (var field in fields.variables) {
-      var fieldElement = field.declaredElement as FieldElement;
+      var fieldElement = field.declaredElement2 as FieldElement;
       if (fieldElement.isAbstract || fieldElement.isExternal) continue;
       if (field.initializer != null) continue;
 
@@ -4059,7 +4059,7 @@ class ErrorVerifier extends RecursiveAstVisitor<void>
     }
     var redirectedElement = redirectedConstructor.staticElement;
     _checkForRedirectToNonConstConstructor(
-      declaration.declaredElement!,
+      declaration.declaredElement2!,
       redirectedElement,
       redirectedConstructor,
     );
@@ -4322,7 +4322,7 @@ class ErrorVerifier extends RecursiveAstVisitor<void>
         if (elementToNode == null) {
           elementToNode = {};
           for (var parameter in parameters) {
-            elementToNode[parameter.declaredElement!] = parameter;
+            elementToNode[parameter.declaredElement2!] = parameter;
           }
         }
 
@@ -4335,7 +4335,7 @@ class ErrorVerifier extends RecursiveAstVisitor<void>
             current = null;
           }
           if (step == parameters.length) {
-            var element = parameter.declaredElement!;
+            var element = parameter.declaredElement2!;
             // This error can only occur if there is a bound, so we can saefly
             // assume `element.bound` is non-`null`.
             errorReporter.reportErrorForToken(
@@ -4769,7 +4769,7 @@ class ErrorVerifier extends RecursiveAstVisitor<void>
         // variance is added to the interface.
         if (!(typeParameter as TypeParameterElementImpl).isLegacyCovariant) {
           var fields = node.fields;
-          var fieldElement = fields.variables.first.declaredElement!;
+          var fieldElement = fields.variables.first.declaredElement2!;
           var fieldName = fields.variables.first.name2;
           Variance fieldVariance = Variance(typeParameter, fieldElement.type);
 
@@ -4887,7 +4887,11 @@ class ErrorVerifier extends RecursiveAstVisitor<void>
     checkOne(_enclosingClass!.supertype);
     _enclosingClass!.interfaces.forEach(checkOne);
     _enclosingClass!.mixins.forEach(checkOne);
-    _enclosingClass!.superclassConstraints.forEach(checkOne);
+
+    final enclosingClass = _enclosingClass;
+    if (enclosingClass is MixinElement) {
+      enclosingClass.superclassConstraints.forEach(checkOne);
+    }
   }
 
   /// Check for invalid variance positions in members of a class or mixin.
@@ -5284,7 +5288,7 @@ class ErrorVerifier extends RecursiveAstVisitor<void>
       if (fieldDeclaration is FieldDeclaration) {
         for (VariableDeclaration field in fieldDeclaration.fields.variables) {
           if (field.initializer == null) {
-            fields.add(field.declaredElement as FieldElement);
+            fields.add(field.declaredElement2 as FieldElement);
           }
         }
       }

pkg/analyzer/lib/src/generated/ffi_verifier.dart

@@ -86,7 +86,7 @@ class FfiVerifier extends RecursiveAstVisitor<void> {
         if (className == _structClassName || className == _unionClassName) {
           inCompound = true;
           compound = node;
-          if (node.declaredElement!.isEmptyStruct) {
+          if (node.declaredElement2!.isEmptyStruct) {
             _errorReporter.reportErrorForToken(FfiCode.EMPTY_STRUCT, node.name2,
                 [node.name2.lexeme, className]);
           }
@@ -148,13 +148,13 @@ class FfiVerifier extends RecursiveAstVisitor<void> {
     }
 
     if (inCompound) {
-      if (node.declaredElement!.typeParameters.isNotEmpty) {
+      if (node.declaredElement2!.typeParameters.isNotEmpty) {
         _errorReporter.reportErrorForToken(
             FfiCode.GENERIC_STRUCT_SUBCLASS, node.name2, [node.name2.lexeme]);
       }
       final implementsClause = node.implementsClause;
       if (implementsClause != null) {
-        final compoundType = node.declaredElement!.thisType;
+        final compoundType = node.declaredElement2!.thisType;
         final structType = compoundType.superclass!;
         final ffiLibrary = structType.element2.library;
         final finalizableElement = ffiLibrary.getClass(_finalizableClassName)!;
@@ -194,7 +194,7 @@ class FfiVerifier extends RecursiveAstVisitor<void> {
     _checkFfiNative(
       errorNode: node,
       annotations: node.metadata,
-      declarationElement: node.declaredElement as ExecutableElement,
+      declarationElement: node.declaredElement2!,
       formalParameterList: node.functionExpression.parameters,
     );
     super.visitFunctionDeclaration(node);
@@ -246,7 +246,7 @@ class FfiVerifier extends RecursiveAstVisitor<void> {
     _checkFfiNative(
         errorNode: node,
         annotations: node.metadata,
-        declarationElement: node.declaredElement as ExecutableElement,
+        declarationElement: node.declaredElement2!,
         formalParameterList: node.parameters);
     super.visitMethodDeclaration(node);
   }

pkg/analyzer/lib/src/generated/resolver.dart

@@ -741,22 +741,22 @@ class ResolverVisitor extends ThrowingAstVisitor<void>
           node is TopLevelVariableDeclaration;
     }
 
-    void forClassElement(ClassElement parentElement) {
+    void forClassElement(InterfaceElement parentElement) {
       enclosingClass = parentElement;
     }
 
     if (parent is ClassDeclaration) {
-      forClassElement(parent.declaredElement!);
+      forClassElement(parent.declaredElement2!);
       return true;
     }
 
     if (parent is ExtensionDeclaration) {
-      enclosingExtension = parent.declaredElement!;
+      enclosingExtension = parent.declaredElement2!;
       return true;
     }
 
     if (parent is MixinDeclaration) {
-      forClassElement(parent.declaredElement!);
+      forClassElement(parent.declaredElement2!);
       return true;
     }
 
@@ -1142,7 +1142,7 @@ class ResolverVisitor extends ThrowingAstVisitor<void>
     //
     var outerType = enclosingClass;
     try {
-      enclosingClass = node.declaredElement;
+      enclosingClass = node.declaredElement2;
       checkUnreachableNode(node);
       node.visitChildren(this);
       elementResolver.visitClassDeclaration(node);
@@ -1238,11 +1238,11 @@ class ResolverVisitor extends ThrowingAstVisitor<void>
     flowAnalysis.executableDeclaration_enter(node, node.parameters,
         isClosure: false);
 
-    var returnType = node.declaredElement!.type.returnType;
+    var returnType = node.declaredElement2!.type.returnType;
 
     var outerFunction = _enclosingFunction;
     try {
-      _enclosingFunction = node.declaredElement;
+      _enclosingFunction = node.declaredElement2;
       assert(_thisType == null);
       _setupThisType();
       checkUnreachableNode(node);
@@ -1400,7 +1400,7 @@ class ResolverVisitor extends ThrowingAstVisitor<void>
     node.metadata.accept(this);
     checkUnreachableNode(node);
 
-    var element = node.declaredElement as ConstFieldElementImpl;
+    var element = node.declaredElement2 as ConstFieldElementImpl;
     var initializer = element.constantInitializer;
     if (initializer is InstanceCreationExpression) {
       var constructorName = initializer.constructorName;
@@ -1479,7 +1479,7 @@ class ResolverVisitor extends ThrowingAstVisitor<void>
     //
     var outerType = enclosingClass;
     try {
-      enclosingClass = node.declaredElement;
+      enclosingClass = node.declaredElement2;
       checkUnreachableNode(node);
       node.visitChildren(this);
       elementResolver.visitEnumDeclaration(node);
@@ -1538,7 +1538,7 @@ class ResolverVisitor extends ThrowingAstVisitor<void>
   void visitExtensionDeclaration(ExtensionDeclaration node) {
     var outerExtension = enclosingExtension;
     try {
-      enclosingExtension = node.declaredElement!;
+      enclosingExtension = node.declaredElement2!;
       checkUnreachableNode(node);
       node.visitChildren(this);
       elementResolver.visitExtensionDeclaration(node);
@@ -1632,11 +1632,11 @@ class ResolverVisitor extends ThrowingAstVisitor<void>
       isClosure: isLocal,
     );
 
-    var functionType = node.declaredElement!.type;
+    var functionType = node.declaredElement2!.type;
 
     var outerFunction = _enclosingFunction;
     try {
-      _enclosingFunction = node.declaredElement;
+      _enclosingFunction = node.declaredElement2;
       checkUnreachableNode(node);
       node.documentationComment?.accept(this);
       node.metadata.accept(this);
@@ -1935,11 +1935,11 @@ class ResolverVisitor extends ThrowingAstVisitor<void>
     flowAnalysis.executableDeclaration_enter(node, node.parameters,
         isClosure: false);
 
-    DartType returnType = node.declaredElement!.returnType;
+    DartType returnType = node.declaredElement2!.returnType;
 
     var outerFunction = _enclosingFunction;
     try {
-      _enclosingFunction = node.declaredElement;
+      _enclosingFunction = node.declaredElement2;
       assert(_thisType == null);
       _setupThisType();
       checkUnreachableNode(node);
@@ -2015,7 +2015,7 @@ class ResolverVisitor extends ThrowingAstVisitor<void>
     //
     var outerType = enclosingClass;
     try {
-      enclosingClass = node.declaredElement!;
+      enclosingClass = node.declaredElement2!;
       checkUnreachableNode(node);
       node.visitChildren(this);
       elementResolver.visitMixinDeclaration(node);
@@ -2494,7 +2494,7 @@ class ResolverVisitor extends ThrowingAstVisitor<void>
   void visitVariableDeclaration(VariableDeclaration node) {
     _variableDeclarationResolver.resolve(node as VariableDeclarationImpl);
 
-    var declaredElement = node.declaredElement!;
+    var declaredElement = node.declaredElement2!;
 
     var initializer = node.initializer;
     var parent = node.parent as VariableDeclarationList;
@@ -2558,7 +2558,7 @@ class ResolverVisitor extends ThrowingAstVisitor<void>
   }
 
   void _checkTopLevelCycle(VariableDeclaration node) {
-    var element = node.declaredElement;
+    var element = node.declaredElement2;
     if (element is! PropertyInducingElementImpl) {
       return;
     }
@@ -3018,7 +3018,7 @@ class ScopeResolverVisitor extends UnifyingAstVisitor<void> {
   void visitClassDeclaration(ClassDeclaration node) {
     Scope outerScope = nameScope;
     try {
-      ClassElement element = node.declaredElement!;
+      ClassElement element = node.declaredElement2!;
       node.metadata.accept(this);
 
       nameScope = TypeParameterScope(
@@ -3028,7 +3028,7 @@ class ScopeResolverVisitor extends UnifyingAstVisitor<void> {
       _setNodeNameScope(node, nameScope);
       visitClassDeclarationInScope(node);
 
-      nameScope = ClassScope(nameScope, element);
+      nameScope = InterfaceScope(nameScope, element);
       visitClassMembersInScope(node);
     } finally {
       nameScope = outerScope;
@@ -3053,8 +3053,8 @@ class ScopeResolverVisitor extends UnifyingAstVisitor<void> {
     node.metadata.accept(this);
     Scope outerScope = nameScope;
     try {
-      ClassElement element = node.declaredElement!;
-      nameScope = ClassScope(
+      ClassElement element = node.declaredElement2!;
+      nameScope = InterfaceScope(
         TypeParameterScope(nameScope, element.typeParameters),
         element,
       );
@@ -3086,7 +3086,7 @@ class ScopeResolverVisitor extends UnifyingAstVisitor<void> {
     (node.body as FunctionBodyImpl).localVariableInfo = _localVariableInfo;
     Scope outerScope = nameScope;
     try {
-      ConstructorElement element = node.declaredElement!;
+      ConstructorElement element = node.declaredElement2!;
 
       node.metadata.accept(this);
       node.returnType.accept(this);
@@ -3126,7 +3126,7 @@ class ScopeResolverVisitor extends UnifyingAstVisitor<void> {
 
   @override
   void visitDeclaredIdentifier(DeclaredIdentifier node) {
-    _define(node.declaredElement!);
+    _define(node.declaredElement2!);
     super.visitDeclaredIdentifier(node);
   }
 
@@ -3150,7 +3150,7 @@ class ScopeResolverVisitor extends UnifyingAstVisitor<void> {
   void visitEnumDeclaration(EnumDeclaration node) {
     Scope outerScope = nameScope;
     try {
-      ClassElement element = node.declaredElement!;
+      final element = node.declaredElement2!;
       node.metadata.accept(this);
 
       nameScope = TypeParameterScope(
@@ -3160,7 +3160,7 @@ class ScopeResolverVisitor extends UnifyingAstVisitor<void> {
       _setNodeNameScope(node, nameScope);
       visitEnumDeclarationInScope(node);
 
-      nameScope = ClassScope(nameScope, element);
+      nameScope = InterfaceScope(nameScope, element);
       visitEnumMembersInScope(node);
     } finally {
       nameScope = outerScope;
@@ -3189,7 +3189,7 @@ class ScopeResolverVisitor extends UnifyingAstVisitor<void> {
   void visitExtensionDeclaration(ExtensionDeclaration node) {
     Scope outerScope = nameScope;
     try {
-      ExtensionElement element = node.declaredElement!;
+      ExtensionElement element = node.declaredElement2!;
       node.metadata.accept(this);
 
       nameScope = TypeParameterScope(
@@ -3262,7 +3262,7 @@ class ScopeResolverVisitor extends UnifyingAstVisitor<void> {
         parent.declaredElement!.parameters,
       );
     } else if (parent is FunctionTypeAlias) {
-      var aliasedElement = parent.declaredElement!.aliasedElement;
+      var aliasedElement = parent.declaredElement2!.aliasedElement;
       var functionElement = aliasedElement as GenericFunctionTypeElement;
       nameScope = FormalParameterScope(
         nameScope,
@@ -3271,7 +3271,7 @@ class ScopeResolverVisitor extends UnifyingAstVisitor<void> {
     } else if (parent is MethodDeclaration) {
       nameScope = FormalParameterScope(
         nameScope,
-        parent.declaredElement!.parameters,
+        parent.declaredElement2!.parameters,
       );
     }
   }
@@ -3309,10 +3309,10 @@ class ScopeResolverVisitor extends UnifyingAstVisitor<void> {
     Scope outerScope = nameScope;
     try {
       _enclosingClosure = node.parent is FunctionDeclarationStatement
-          ? node.declaredElement
+          ? node.declaredElement2
           : null;
       node.metadata.accept(this);
-      var element = node.declaredElement!;
+      var element = node.declaredElement2!;
       nameScope = TypeParameterScope(
         nameScope,
         element.typeParameters,
@@ -3366,7 +3366,7 @@ class ScopeResolverVisitor extends UnifyingAstVisitor<void> {
     node.metadata.accept(this);
     Scope outerScope = nameScope;
     try {
-      var element = node.declaredElement!;
+      var element = node.declaredElement2!;
       nameScope = TypeParameterScope(nameScope, element.typeParameters);
       visitFunctionTypeAliasInScope(node);
     } finally {
@@ -3440,7 +3440,7 @@ class ScopeResolverVisitor extends UnifyingAstVisitor<void> {
     node.metadata.accept(this);
     Scope outerScope = nameScope;
     try {
-      var element = node.declaredElement as TypeAliasElement;
+      var element = node.declaredElement2 as TypeAliasElement;
       nameScope = TypeParameterScope(nameScope, element.typeParameters);
       _setNodeNameScope(node, nameScope);
       visitGenericTypeAliasInScope(node);
@@ -3488,7 +3488,7 @@ class ScopeResolverVisitor extends UnifyingAstVisitor<void> {
     node.metadata.accept(this);
     Scope outerScope = nameScope;
     try {
-      ExecutableElement element = node.declaredElement!;
+      ExecutableElement element = node.declaredElement2!;
       nameScope = TypeParameterScope(
         nameScope,
         element.typeParameters,
@@ -3530,14 +3530,14 @@ class ScopeResolverVisitor extends UnifyingAstVisitor<void> {
   void visitMixinDeclaration(MixinDeclaration node) {
     Scope outerScope = nameScope;
     try {
-      ClassElement element = node.declaredElement!;
+      final element = node.declaredElement2!;
       node.metadata.accept(this);
 
       nameScope = TypeParameterScope(nameScope, element.typeParameters);
       _setNodeNameScope(node, nameScope);
       visitMixinDeclarationInScope(node);
 
-      nameScope = ClassScope(nameScope, element);
+      nameScope = InterfaceScope(nameScope, element);
       visitMixinMembersInScope(node);
     } finally {
       nameScope = outerScope;
@@ -3688,7 +3688,7 @@ class ScopeResolverVisitor extends UnifyingAstVisitor<void> {
     super.visitVariableDeclaration(node);
 
     if (node.parent!.parent is ForParts) {
-      _define(node.declaredElement!);
+      _define(node.declaredElement2!);
     }
   }
 

pkg/analyzer/lib/src/lint/linter.dart

@@ -336,7 +336,7 @@ class LinterContextImpl implements LinterContext {
 
   @override
   bool canBeConstConstructor(covariant ConstructorDeclarationImpl node) {
-    var element = node.declaredElement!;
+    var element = node.declaredElement2!;
 
     final classElement = element.enclosingElement3;
     if (classElement is ClassElement && classElement.hasNonFinalField) {

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

@@ -858,7 +858,7 @@ class AstBinaryWriter extends ThrowingAstVisitor<void> {
       f();
     } else {
       var elements = node.typeParameters
-          .map((typeParameter) => typeParameter.declaredElement!)
+          .map((typeParameter) => typeParameter.declaredElement2!)
           .toList();
       _sink.localElements.withElements(elements, () {
         f();

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

@@ -25,32 +25,32 @@ class DefaultTypesBuilder {
   void build(List<AstNode> nodes) {
     for (var node in nodes) {
       if (node is ClassDeclaration) {
-        var element = node.declaredElement!;
+        var element = node.declaredElement2!;
         _breakSelfCycles(node.typeParameters);
         _breakRawTypeCycles(element, node.typeParameters);
         _computeBounds(element, node.typeParameters);
       } else if (node is ClassTypeAlias) {
-        var element = node.declaredElement!;
+        var element = node.declaredElement2!;
         _breakSelfCycles(node.typeParameters);
         _breakRawTypeCycles(element, node.typeParameters);
         _computeBounds(element, node.typeParameters);
       } else if (node is EnumDeclaration) {
-        var element = node.declaredElement!;
+        var element = node.declaredElement2!;
         _breakSelfCycles(node.typeParameters);
         _breakRawTypeCycles(element, node.typeParameters);
         _computeBounds(element, node.typeParameters);
       } else if (node is FunctionTypeAlias) {
-        var element = node.declaredElement!;
+        var element = node.declaredElement2!;
         _breakSelfCycles(node.typeParameters);
         _breakRawTypeCycles(element, node.typeParameters);
         _computeBounds(element, node.typeParameters);
       } else if (node is GenericTypeAlias) {
-        var element = node.declaredElement!;
+        var element = node.declaredElement2!;
         _breakSelfCycles(node.typeParameters);
         _breakRawTypeCycles(element, node.typeParameters);
         _computeBounds(element, node.typeParameters);
       } else if (node is MixinDeclaration) {
-        var element = node.declaredElement!;
+        var element = node.declaredElement2!;
         _breakSelfCycles(node.typeParameters);
         _breakRawTypeCycles(element, node.typeParameters);
         _computeBounds(element, node.typeParameters);
@@ -152,7 +152,7 @@ class DefaultTypesBuilder {
     if (parameterList == null) return;
 
     for (var parameter in parameterList.typeParameters) {
-      var element = parameter.declaredElement as TypeParameterElementImpl;
+      var element = parameter.declaredElement2 as TypeParameterElementImpl;
       var defaultType = element.defaultType;
       if (defaultType is TypeBuilder) {
         var builtType = defaultType.build();
@@ -182,7 +182,7 @@ class DefaultTypesBuilder {
     var bounds = <DartType>[];
     for (int i = 0; i < length; i++) {
       var node = nodes[i];
-      elements.add(node.declaredElement as TypeParameterElementImpl);
+      elements.add(node.declaredElement2 as TypeParameterElementImpl);
       bounds.add(node.bound?.type ?? dynamicType);
     }
 
@@ -228,7 +228,7 @@ class DefaultTypesBuilder {
 
     // Set computed TypeBuilder(s) as default types.
     for (var i = 0; i < length; i++) {
-      var element = nodes[i].declaredElement as TypeParameterElementImpl;
+      var element = nodes[i].declaredElement2 as TypeParameterElementImpl;
       element.defaultType = bounds[i];
     }
   }

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

@@ -98,7 +98,7 @@ class ElementBuilder extends ThrowingAstVisitor<void> {
     _setCodeRange(element, node);
     _setDocumentation(element, node);
 
-    node.declaredElement = element;
+    node.declaredElement2 = element;
     _linker.elementNodes[element] = node;
 
     var reference = _enclosingContext.addClass(name, element);
@@ -132,7 +132,7 @@ class ElementBuilder extends ThrowingAstVisitor<void> {
     _setCodeRange(element, node);
     _setDocumentation(element, node);
 
-    node.declaredElement = element;
+    node.declaredElement2 = element;
     _linker.elementNodes[element] = node;
 
     var reference = _enclosingContext.addClass(name, element);
@@ -178,7 +178,7 @@ class ElementBuilder extends ThrowingAstVisitor<void> {
       element.constantInitializers = node.initializers;
     }
 
-    node.declaredElement = element;
+    node.declaredElement2 = element;
     _linker.elementNodes[element] = node;
 
     var reference = _enclosingContext.addConstructor(element);
@@ -205,7 +205,7 @@ class ElementBuilder extends ThrowingAstVisitor<void> {
     _setCodeRange(element, node);
     _setDocumentation(element, node);
 
-    node.declaredElement = element;
+    node.declaredElement2 = element;
     _linker.elementNodes[element] = node;
 
     var reference = _enclosingContext.addEnum(name, element);
@@ -406,7 +406,7 @@ class ElementBuilder extends ThrowingAstVisitor<void> {
     _setCodeRange(element, node);
     _setDocumentation(element, node);
 
-    node.declaredElement = element;
+    node.declaredElement2 = element;
     _linker.elementNodes[element] = node;
 
     var refName = name ?? '${_nextUnnamedExtensionId++}';
@@ -478,7 +478,7 @@ class ElementBuilder extends ThrowingAstVisitor<void> {
       _enclosingContext.addNonSyntheticField(element);
 
       _linker.elementNodes[element] = variable;
-      variable.declaredElement = element;
+      variable.declaredElement2 = element;
     }
     _buildType(node.fields.type);
   }
@@ -585,7 +585,7 @@ class ElementBuilder extends ThrowingAstVisitor<void> {
     _setCodeRange(executableElement, node);
     _setDocumentation(executableElement, node);
 
-    node.declaredElement = executableElement;
+    node.declaredElement2 = executableElement;
     _linker.elementNodes[executableElement] = node;
 
     _buildExecutableElementChildren(
@@ -615,7 +615,7 @@ class ElementBuilder extends ThrowingAstVisitor<void> {
     _setCodeRange(element, node);
     _setDocumentation(element, node);
 
-    node.declaredElement = element;
+    node.declaredElement2 = element;
     _linker.elementNodes[element] = node;
 
     var reference = _enclosingContext.addTypeAlias(name, element);
@@ -723,7 +723,7 @@ class ElementBuilder extends ThrowingAstVisitor<void> {
     _setCodeRange(element, node);
     _setDocumentation(element, node);
 
-    node.declaredElement = element;
+    node.declaredElement2 = element;
     _linker.elementNodes[element] = node;
 
     var reference = _enclosingContext.addTypeAlias(name, element);
@@ -836,7 +836,7 @@ class ElementBuilder extends ThrowingAstVisitor<void> {
     _setCodeRange(executableElement, node);
     _setDocumentation(executableElement, node);
 
-    node.declaredElement = executableElement;
+    node.declaredElement2 = executableElement;
     _linker.elementNodes[executableElement] = node;
 
     _buildExecutableElementChildren(
@@ -859,7 +859,7 @@ class ElementBuilder extends ThrowingAstVisitor<void> {
     _setCodeRange(element, node);
     _setDocumentation(element, node);
 
-    node.declaredElement = element;
+    node.declaredElement2 = element;
     _linker.elementNodes[element] = node;
 
     var reference = _enclosingContext.addMixin(name, element);
@@ -1038,7 +1038,7 @@ class ElementBuilder extends ThrowingAstVisitor<void> {
 
       _linker.elementNodes[element] = variable;
       _enclosingContext.addTopLevelVariable(name, element);
-      variable.declaredElement = element;
+      variable.declaredElement2 = element;
 
       var getter = element.getter;
       if (getter is PropertyAccessorElementImpl) {
@@ -1070,7 +1070,7 @@ class ElementBuilder extends ThrowingAstVisitor<void> {
     element.metadata = _buildAnnotations(node.metadata);
     _setCodeRange(element, node);
 
-    node.declaredElement = element;
+    node.declaredElement2 = element;
     _linker.elementNodes[element] = node;
     _enclosingContext.addTypeParameter(name, element);
 
@@ -1092,7 +1092,7 @@ class ElementBuilder extends ThrowingAstVisitor<void> {
   }
 
   void _buildClass(ClassDeclaration node) {
-    var element = node.declaredElement as ClassElementImpl;
+    var element = node.declaredElement2 as ClassElementImpl;
     var hasConstConstructor = node.members.any((e) {
       return e is ConstructorDeclaration && e.constKeyword != null;
     });
@@ -1137,7 +1137,7 @@ class ElementBuilder extends ThrowingAstVisitor<void> {
   }
 
   void _buildMixin(MixinDeclaration node) {
-    var element = node.declaredElement as MixinElementImpl;
+    var element = node.declaredElement2 as MixinElementImpl;
     var hasConstConstructor = node.members.any((e) {
       return e is ConstructorDeclaration && e.constKeyword != null;
     });

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

@@ -208,6 +208,6 @@ class FunctionTypeBuilder extends TypeBuilder {
     TypeParameterList? node,
   ) {
     if (node == null) return const [];
-    return node.typeParameters.map((n) => n.declaredElement!).toList();
+    return node.typeParameters.map((n) => n.declaredElement2!).toList();
   }
 }

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

@@ -212,7 +212,7 @@ class LibraryBuilder {
               executable.body.accept(collector);
             }
           }
-          var element = declaration.declaredElement as MixinElementImpl;
+          var element = declaration.declaredElement2 as MixinElementImpl;
           element.superInvokedNames = names.toList();
         }
       }

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

@@ -52,7 +52,7 @@ class DeclarationBuilder {
     }
 
     for (final entry in fromNode._classMap.entries) {
-      final element = entry.key.declaredElement as ClassElement;
+      final element = entry.key.declaredElement2!;
       final declaration = entry.value;
       declaration.element = element;
       fromElement._classMap[element] = declaration;
@@ -214,7 +214,7 @@ class DeclarationBuilderFromNode {
     assert(!_classMap.containsKey(node));
     return IntrospectableClassDeclarationImpl._(
       id: macro.RemoteInstance.uniqueId,
-      identifier: _declaredIdentifier(node.name2, node.declaredElement!),
+      identifier: _declaredIdentifier(node.name2, node.declaredElement2!),
       typeParameters: _typeParameters(node.typeParameters),
       interfaces: _typeAnnotations(node.implementsClause?.interfaces),
       isAbstract: node.abstractKeyword != null,
@@ -290,7 +290,7 @@ class DeclarationBuilderFromNode {
   ) {
     return macro.TypeParameterDeclarationImpl(
       id: macro.RemoteInstance.uniqueId,
-      identifier: _declaredIdentifier(node.name2, node.declaredElement!),
+      identifier: _declaredIdentifier(node.name2, node.declaredElement2!),
       bound: node.bound.mapOrNull(_typeAnnotation),
     );
   }

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

@@ -319,7 +319,7 @@ class NamedTypeBuilder extends TypeBuilder {
   static List<TypeParameterElement> _typeParameters(TypeParameterList? node) {
     if (node != null) {
       return node.typeParameters
-          .map<TypeParameterElement>((p) => p.declaredElement!)
+          .map<TypeParameterElement>((p) => p.declaredElement2!)
           .toList();
     } else {
       return const <TypeParameterElement>[];

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

@@ -52,7 +52,7 @@ class ReferenceResolver extends ThrowingAstVisitor<void> {
   void visitClassDeclaration(ClassDeclaration node) {
     var outerScope = scope;
 
-    var element = node.declaredElement as ClassElementImpl;
+    var element = node.declaredElement2 as ClassElementImpl;
 
     scope = TypeParameterScope(scope, element.typeParameters);
 
@@ -61,7 +61,7 @@ class ReferenceResolver extends ThrowingAstVisitor<void> {
     node.implementsClause?.accept(this);
     node.withClause?.accept(this);
 
-    scope = ClassScope(scope, element);
+    scope = InterfaceScope(scope, element);
     LinkingNodeContext(node, scope);
 
     node.members.accept(this);
@@ -74,7 +74,7 @@ class ReferenceResolver extends ThrowingAstVisitor<void> {
   void visitClassTypeAlias(ClassTypeAlias node) {
     var outerScope = scope;
 
-    var element = node.declaredElement as ClassElementImpl;
+    var element = node.declaredElement2 as ClassElementImpl;
 
     scope = TypeParameterScope(scope, element.typeParameters);
     LinkingNodeContext(node, scope);
@@ -98,7 +98,7 @@ class ReferenceResolver extends ThrowingAstVisitor<void> {
   void visitConstructorDeclaration(ConstructorDeclaration node) {
     var outerScope = scope;
 
-    var element = node.declaredElement as ConstructorElementImpl;
+    var element = node.declaredElement2 as ConstructorElementImpl;
 
     scope = TypeParameterScope(scope, element.typeParameters);
     LinkingNodeContext(node, scope);
@@ -117,7 +117,7 @@ class ReferenceResolver extends ThrowingAstVisitor<void> {
   void visitEnumDeclaration(EnumDeclaration node) {
     var outerScope = scope;
 
-    var element = node.declaredElement as EnumElementImpl;
+    var element = node.declaredElement2 as EnumElementImpl;
 
     scope = TypeParameterScope(scope, element.typeParameters);
 
@@ -125,7 +125,7 @@ class ReferenceResolver extends ThrowingAstVisitor<void> {
     node.implementsClause?.accept(this);
     node.withClause?.accept(this);
 
-    scope = ClassScope(scope, element);
+    scope = InterfaceScope(scope, element);
     LinkingNodeContext(node, scope);
 
     node.members.accept(this);
@@ -146,7 +146,7 @@ class ReferenceResolver extends ThrowingAstVisitor<void> {
   void visitExtensionDeclaration(ExtensionDeclaration node) {
     var outerScope = scope;
 
-    var element = node.declaredElement as ExtensionElementImpl;
+    var element = node.declaredElement2 as ExtensionElementImpl;
 
     scope = TypeParameterScope(scope, element.typeParameters);
 
@@ -192,7 +192,7 @@ class ReferenceResolver extends ThrowingAstVisitor<void> {
   void visitFunctionDeclaration(FunctionDeclaration node) {
     var outerScope = scope;
 
-    var element = node.declaredElement as ExecutableElementImpl;
+    var element = node.declaredElement2 as ExecutableElementImpl;
 
     scope = TypeParameterScope(outerScope, element.typeParameters);
     LinkingNodeContext(node, scope);
@@ -214,7 +214,7 @@ class ReferenceResolver extends ThrowingAstVisitor<void> {
   void visitFunctionTypeAlias(FunctionTypeAlias node) {
     var outerScope = scope;
 
-    var element = node.declaredElement as TypeAliasElementImpl;
+    var element = node.declaredElement2 as TypeAliasElementImpl;
 
     scope = TypeParameterScope(outerScope, element.typeParameters);
 
@@ -267,7 +267,7 @@ class ReferenceResolver extends ThrowingAstVisitor<void> {
   void visitGenericTypeAlias(GenericTypeAlias node) {
     var outerScope = scope;
 
-    var element = node.declaredElement as TypeAliasElementImpl;
+    var element = node.declaredElement2 as TypeAliasElementImpl;
 
     scope = TypeParameterScope(outerScope, element.typeParameters);
 
@@ -294,7 +294,7 @@ class ReferenceResolver extends ThrowingAstVisitor<void> {
   void visitMethodDeclaration(MethodDeclaration node) {
     var outerScope = scope;
 
-    var element = node.declaredElement as ExecutableElementImpl;
+    var element = node.declaredElement2 as ExecutableElementImpl;
 
     scope = TypeParameterScope(scope, element.typeParameters);
     LinkingNodeContext(node, scope);
@@ -311,7 +311,7 @@ class ReferenceResolver extends ThrowingAstVisitor<void> {
   void visitMixinDeclaration(MixinDeclaration node) {
     var outerScope = scope;
 
-    var element = node.declaredElement as MixinElementImpl;
+    var element = node.declaredElement2 as MixinElementImpl;
 
     scope = TypeParameterScope(scope, element.typeParameters);
 
@@ -319,7 +319,7 @@ class ReferenceResolver extends ThrowingAstVisitor<void> {
     node.onClause?.accept(this);
     node.implementsClause?.accept(this);
 
-    scope = ClassScope(scope, element);
+    scope = InterfaceScope(scope, element);
     LinkingNodeContext(node, scope);
 
     node.members.accept(this);
@@ -424,7 +424,7 @@ class ReferenceResolver extends ThrowingAstVisitor<void> {
     var bound = node.bound;
     if (bound != null) {
       bound.accept(this);
-      var element = node.declaredElement as TypeParameterElementImpl;
+      var element = node.declaredElement2 as TypeParameterElementImpl;
       element.bound = bound.type;
     }
   }

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

@@ -40,22 +40,22 @@ void computeSimplyBounded(Linker linker) {
     walker.walk(node);
     var node2 = node._node;
     if (node2 is ClassDeclaration) {
-      var element = node2.declaredElement as ClassElementImpl;
+      var element = node2.declaredElement2 as ClassElementImpl;
       element.isSimplyBounded = node.isSimplyBounded;
     } else if (node2 is ClassTypeAlias) {
-      var element = node2.declaredElement as ClassElementImpl;
+      var element = node2.declaredElement2 as ClassElementImpl;
       element.isSimplyBounded = node.isSimplyBounded;
     } else if (node2 is EnumDeclaration) {
-      var element = node2.declaredElement as EnumElementImpl;
+      var element = node2.declaredElement2 as EnumElementImpl;
       element.isSimplyBounded = node.isSimplyBounded;
     } else if (node2 is GenericTypeAlias) {
-      var element = node2.declaredElement as TypeAliasElementImpl;
+      var element = node2.declaredElement2 as TypeAliasElementImpl;
       element.isSimplyBounded = node.isSimplyBounded;
     } else if (node2 is FunctionTypeAlias) {
-      var element = node2.declaredElement as TypeAliasElementImpl;
+      var element = node2.declaredElement2 as TypeAliasElementImpl;
       element.isSimplyBounded = node.isSimplyBounded;
     } else if (node2 is MixinDeclaration) {
-      var element = node2.declaredElement as MixinElementImpl;
+      var element = node2.declaredElement2 as MixinElementImpl;
       element.isSimplyBounded = node.isSimplyBounded;
     } else {
       throw UnimplementedError('${node2.runtimeType}');

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

@@ -15,12 +15,12 @@ class TypeAliasSelfReferenceFinder {
           if (node is FunctionTypeAlias) {
             var finder = _Finder(linker, node);
             finder.functionTypeAlias(node);
-            var element = node.declaredElement as TypeAliasElementImpl;
+            var element = node.declaredElement2 as TypeAliasElementImpl;
             element.hasSelfReference = finder.hasSelfReference;
           } else if (node is GenericTypeAlias) {
             var finder = _Finder(linker, node);
             finder.genericTypeAlias(node);
-            var element = node.declaredElement as TypeAliasElementImpl;
+            var element = node.declaredElement2 as TypeAliasElementImpl;
             element.hasSelfReference = finder.hasSelfReference;
           }
         }

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

@@ -117,7 +117,7 @@ class TypesBuilder {
   }
 
   void _classDeclaration(ClassDeclaration node) {
-    var element = node.declaredElement as ClassElementImpl;
+    var element = node.declaredElement2 as ClassElementImpl;
 
     var extendsClause = node.extendsClause;
     if (extendsClause != null) {
@@ -143,7 +143,7 @@ class TypesBuilder {
   }
 
   void _classTypeAlias(ClassTypeAlias node) {
-    var element = node.declaredElement as ClassElementImpl;
+    var element = node.declaredElement2 as ClassElementImpl;
 
     var superType = node.superclass.type;
     if (superType is InterfaceType && _isInterfaceTypeInterface(superType)) {
@@ -181,7 +181,7 @@ class TypesBuilder {
           returnType = _dynamicType;
         }
       }
-      var element = node.declaredElement as ExecutableElementImpl;
+      var element = node.declaredElement2 as ExecutableElementImpl;
       element.returnType = returnType;
     } else if (node is FunctionTypeAlias) {
       _functionTypeAlias(node);
@@ -200,7 +200,7 @@ class TypesBuilder {
           returnType = _dynamicType;
         }
       }
-      var element = node.declaredElement as ExecutableElementImpl;
+      var element = node.declaredElement2 as ExecutableElementImpl;
       element.returnType = returnType;
     } else if (node is MixinDeclaration) {
       _mixinDeclaration(node);
@@ -213,7 +213,7 @@ class TypesBuilder {
       var type = node.type?.type;
       if (type != null) {
         for (var variable in node.variables) {
-          (variable.declaredElement as VariableElementImpl).type = type;
+          (variable.declaredElement2 as VariableElementImpl).type = type;
         }
       }
     } else {
@@ -222,7 +222,7 @@ class TypesBuilder {
   }
 
   void _enumDeclaration(EnumDeclaration node) {
-    var element = node.declaredElement as EnumElementImpl;
+    var element = node.declaredElement2 as EnumElementImpl;
 
     element.mixins = _toInterfaceTypeList(
       node.withClause?.mixinTypes,
@@ -234,7 +234,7 @@ class TypesBuilder {
   }
 
   void _extensionDeclaration(ExtensionDeclaration node) {
-    var element = node.declaredElement as ExtensionElementImpl;
+    var element = node.declaredElement2 as ExtensionElementImpl;
     element.extendedType = node.extendedType.typeOrThrow;
   }
 
@@ -261,7 +261,7 @@ class TypesBuilder {
   }
 
   void _functionTypeAlias(FunctionTypeAlias node) {
-    var element = node.declaredElement as TypeAliasElementImpl;
+    var element = node.declaredElement2 as TypeAliasElementImpl;
     var function = element.aliasedElement as GenericFunctionTypeElementImpl;
     function.returnType = node.returnType?.type ?? _dynamicType;
     element.aliasedType = function.type;
@@ -279,7 +279,7 @@ class TypesBuilder {
   }
 
   void _genericTypeAlias(GenericTypeAlias node) {
-    var element = node.declaredElement as TypeAliasElementImpl;
+    var element = node.declaredElement2 as TypeAliasElementImpl;
     var featureSet = element.library.featureSet;
 
     var typeNode = node.type;
@@ -298,7 +298,7 @@ class TypesBuilder {
   }
 
   void _mixinDeclaration(MixinDeclaration node) {
-    var element = node.declaredElement as MixinElementImpl;
+    var element = node.declaredElement2 as MixinElementImpl;
 
     var constraints = _toInterfaceTypeList(
       node.onClause?.superclassConstraints,
@@ -347,7 +347,7 @@ class TypesBuilder {
     }
 
     return node.typeParameters
-        .map<TypeParameterElement>((p) => p.declaredElement!)
+        .map<TypeParameterElement>((p) => p.declaredElement2!)
         .toList();
   }
 
@@ -518,7 +518,8 @@ class _MixinsInference {
   void perform(List<AstNode> declarations) {
     for (var node in declarations) {
       if (node is ClassDeclaration || node is ClassTypeAlias) {
-        var element = (node as Declaration).declaredElement as ClassElementImpl;
+        var element =
+            (node as Declaration).declaredElement2 as ClassElementImpl;
         element.mixinInferenceCallback = _callbackWhenRecursion;
       }
     }
@@ -568,13 +569,13 @@ class _MixinsInference {
 
   void _inferDeclaration(AstNode node) {
     if (node is ClassDeclaration) {
-      var element = node.declaredElement as ClassElementImpl;
+      var element = node.declaredElement2 as ClassElementImpl;
       _infer(element, node.withClause);
     } else if (node is ClassTypeAlias) {
-      var element = node.declaredElement as ClassElementImpl;
+      var element = node.declaredElement2 as ClassElementImpl;
       _infer(element, node.withClause);
     } else if (node is EnumDeclaration) {
-      var element = node.declaredElement as EnumElementImpl;
+      var element = node.declaredElement2 as EnumElementImpl;
       _infer(element, node.withClause);
     }
   }
@@ -586,10 +587,10 @@ class _MixinsInference {
   void _resetHierarchies(List<AstNode> declarations) {
     for (var declaration in declarations) {
       if (declaration is ClassDeclaration) {
-        var element = declaration.declaredElement as ClassElementImpl;
+        var element = declaration.declaredElement2 as ClassElementImpl;
         element.library.session.classHierarchy.remove(element);
       } else if (declaration is MixinDeclaration) {
-        var element = declaration.declaredElement as MixinElementImpl;
+        var element = declaration.declaredElement2 as MixinElementImpl;
         element.library.session.classHierarchy.remove(element);
       }
     }

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

@@ -164,7 +164,7 @@ class VarianceBuilder {
     try {
       for (var parameter in parameterList.typeParameters) {
         var variance = _computeFunctionType(
-          parameter.declaredElement!,
+          parameter.declaredElement2!,
           returnType: node.returnType?.type,
           typeFormals: null,
           parameters: FunctionTypeBuilder.getParameters(
@@ -210,7 +210,7 @@ class VarianceBuilder {
     _visit.add(node);
     try {
       for (var parameter in parameterList.typeParameters) {
-        var variance = _compute(parameter.declaredElement!, type);
+        var variance = _compute(parameter.declaredElement2!, type);
         _setVariance(parameter, variance);
       }
     } finally {
@@ -247,7 +247,7 @@ class VarianceBuilder {
   }
 
   static void _setVariance(TypeParameter node, Variance variance) {
-    var element = node.declaredElement as TypeParameterElementImpl;
+    var element = node.declaredElement2 as TypeParameterElementImpl;
     element.variance = variance;
   }
 }