Elements. Add PropertyAccessorElement2 and PropertyAccessorFragment.

I found a number of places where we need to access `variable3`, so
it might be convenient to have a common interface that provides it.

Still, there are many places where we want to know that this is
specifically `GetterElement`, to separate interfaces for them are
also useful.

Change-Id: Ib671dc3bdb9a04a022fd74921f8ccedcdba79643
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/395701
Commit-Queue: Konstantin Shcheglov <[email protected]>
Reviewed-by: Brian Wilkerson <[email protected]>

Author: scheglov

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

@@ -52,8 +52,8 @@ class DartDocumentationComputer {
       element,
       ...overridden.superElements,
       ...overridden.interfaceElements,
-      if (element case GetterElement(variable3: var variable?)) variable,
-      if (element case SetterElement(variable3: var variable?)) variable,
+      if (element case PropertyAccessorElement2(variable3: var variable?))
+        variable,
     ];
     for (var candidate in candidates) {
       if (candidate.documentationCommentOrNull != null) {

pkg/analysis_server/lib/src/lsp/handlers/handler_document_color_presentation.dart

@@ -253,8 +253,7 @@ class DocumentColorPresentationHandler
           parent is PrefixedIdentifier ? parent.element : node.element;
 
       return switch (element) {
-        GetterElement(:var variable3) || SetterElement(:var variable3) =>
-          variable3?.isConst ?? false,
+        PropertyAccessorElement2(:var variable3) => variable3?.isConst ?? false,
         VariableElement2() => element.isConst,
         _ => false,
       };

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

@@ -257,13 +257,7 @@ class FeatureComputer {
       return protocol.ElementKind.CLASS;
     } else if (element is FieldElement2 && element.isEnumConstant) {
       return protocol.ElementKind.ENUM_CONSTANT;
-    } else if (element is GetterElement) {
-      var variable = element.variable3;
-      if (variable == null) {
-        return protocol.ElementKind.UNKNOWN;
-      }
-      element = variable;
-    } else if (element is SetterElement) {
+    } else if (element is PropertyAccessorElement2) {
       var variable = element.variable3;
       if (variable == null) {
         return protocol.ElementKind.UNKNOWN;
@@ -467,12 +461,7 @@ class FeatureComputer {
       return 1.0;
     } else if (element is TopLevelVariableElement2 && element.isConst) {
       return 1.0;
-    } else if (element is GetterElement && element.isSynthetic) {
-      var variable = element.variable3;
-      if (variable != null && variable.isStatic && variable.isConst) {
-        return 1.0;
-      }
-    } else if (element is SetterElement && element.isSynthetic) {
+    } else if (element is PropertyAccessorElement2 && element.isSynthetic) {
       var variable = element.variable3;
       if (variable != null && variable.isStatic && variable.isConst) {
         return 1.0;

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

@@ -1492,9 +1492,7 @@ class SuggestionBuilder {
     int? requiredParameterCount;
     bool? hasNamedParameters;
     CompletionDefaultArgumentList? defaultArgumentList;
-    if (element is ExecutableElement2 &&
-        element is! GetterElement &&
-        element is! SetterElement) {
+    if (element is ExecutableElement2 && element is! PropertyAccessorElement2) {
       parameterNames =
           element.formalParameters.map((parameter) {
             return parameter.displayName;

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

@@ -303,8 +303,7 @@ class _FieldFinder extends RecursiveAstVisitor<void> {
     if (node.inSetterContext()) {
       var element = node.writeOrReadElement2;
       var field = switch (element) {
-        GetterElement(:var variable3) => variable3,
-        SetterElement(:var variable3) => variable3,
+        PropertyAccessorElement2(:var variable3) => variable3,
         _ => null,
       };
       if (field is FieldElement2) {

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

@@ -273,11 +273,7 @@ class _ElementReferenceCollector extends RecursiveAstVisitor<void> {
     var staticElement = node.writeOrReadElement2;
     if (staticElement == element) {
       references.add(node);
-    } else if (staticElement is GetterElement) {
-      if (staticElement.variable3 == element) {
-        references.add(node);
-      }
-    } else if (staticElement is SetterElement) {
+    } else if (staticElement is PropertyAccessorElement2) {
       if (staticElement.variable3 == element) {
         references.add(node);
       }

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

@@ -7,13 +7,12 @@ import 'package:analysis_server/src/services/correction/fix/data_driven/element_
 import 'package:analyzer/dart/ast/token.dart';
 import 'package:analyzer/dart/element/element2.dart'
     show
-        LibraryElement2,
-        LibraryFragment,
         ExtensionElement2,
-        GetterElement,
         InterfaceElement2,
+        LibraryElement2,
+        LibraryFragment,
         PrefixElement2,
-        SetterElement;
+        PropertyAccessorElement2;
 import 'package:analyzer/dart/element/type.dart';
 import 'package:analyzer/src/dart/ast/ast.dart';
 
@@ -546,8 +545,8 @@ class _MatcherBuilder {
         var element = node.element;
         // Add enclosing element to the matcher for non top level property
         // accessors when possible.
-        if (element is GetterElement || element is SetterElement) {
-          var enclosingElement = element?.enclosingElement2;
+        if (element is PropertyAccessorElement2) {
+          var enclosingElement = element.enclosingElement2;
           if (enclosingElement is! LibraryElement2) {
             _addMatcher(
               components: [node.name, (enclosingElement?.displayName)!],

pkg/analysis_server/lib/src/utilities/import_analyzer.dart

@@ -121,23 +121,14 @@ class _ElementRecorder {
     int referenceOffset,
     LibraryImport? import,
   ) {
-    switch (referencedElement) {
-      case GetterElement():
-        if (referencedElement.isSynthetic) {
-          var variable = referencedElement.variable3;
-          if (variable == null) {
-            return;
-          }
-          referencedElement = variable;
-        }
-      case SetterElement():
-        if (referencedElement.isSynthetic) {
-          var variable = referencedElement.variable3;
-          if (variable == null) {
-            return;
-          }
-          referencedElement = variable;
+    if (referencedElement is PropertyAccessorElement2) {
+      if (referencedElement.isSynthetic) {
+        var variable = referencedElement.variable3;
+        if (variable == null) {
+          return;
         }
+        referencedElement = variable;
+      }
     }
 
     if (_isBeingMoved(referenceOffset)) {

pkg/analyzer/lib/dart/element/element2.dart

@@ -1071,7 +1071,7 @@ abstract class GenericFunctionTypeFragment implements FunctionTypedFragment {
 /// top-level variable or a field. Induced getters are synthetic.
 ///
 /// Clients may not extend, implement or mix-in this class.
-abstract class GetterElement implements ExecutableElement2 {
+abstract class GetterElement implements PropertyAccessorElement2 {
   @override
   GetterElement get baseElement;
 
@@ -1081,18 +1081,12 @@ abstract class GetterElement implements ExecutableElement2 {
 
   @override
   GetterFragment get firstFragment;
-
-  /// The field or top-level variable associated with this getter.
-  ///
-  /// If this getter was explicitly defined (is not synthetic) then the variable
-  /// associated with it will be synthetic.
-  PropertyInducingElement2? get variable3;
 }
 
 /// The portion of a [GetterElement] contributed by a single declaration.
 ///
 /// Clients may not extend, implement or mix-in this class.
-abstract class GetterFragment implements ExecutableFragment {
+abstract class GetterFragment implements PropertyAccessorFragment {
   /// The setter that corresponds to (has the same name as) this getter, or
   /// `null` if there is no corresponding setter.
   SetterFragment? get correspondingSetter2;
@@ -1113,12 +1107,6 @@ abstract class GetterFragment implements ExecutableFragment {
   //  but can't because the Impl class supports both getters and setters.
   // @override
   // GetterElement get element;
-
-  /// The field or top-level variable associated with this getter.
-  ///
-  /// If this getter was explicitly defined (is not synthetic) then the variable
-  /// associated with it will be synthetic.
-  PropertyInducingFragment? get variable3;
 }
 
 /// An element whose instance members can refer to `this`.
@@ -2077,6 +2065,47 @@ abstract class PromotableFragment implements VariableFragment {
   PromotableFragment? get previousFragment;
 }
 
+/// A getter or a setter.
+///
+/// Property accessors can either be defined explicitly or they can be induced
+/// by either a top-level variable or a field. Induced property accessors are
+/// synthetic.
+///
+/// Clients may not extend, implement or mix-in this class.
+abstract class PropertyAccessorElement2 implements ExecutableElement2 {
+  @override
+  PropertyAccessorElement2 get baseElement;
+
+  @override
+  PropertyAccessorFragment get firstFragment;
+
+  /// The field or top-level variable associated with this getter.
+  ///
+  /// If this getter was explicitly defined (is not synthetic) then the variable
+  /// associated with it will be synthetic.
+  PropertyInducingElement2? get variable3;
+}
+
+/// The portion of a [GetterElement] contributed by a single declaration.
+///
+/// Clients may not extend, implement or mix-in this class.
+abstract class PropertyAccessorFragment implements ExecutableFragment {
+  @override
+  PropertyAccessorElement2 get element;
+
+  @override
+  PropertyAccessorFragment? get nextFragment;
+
+  @override
+  PropertyAccessorFragment? get previousFragment;
+
+  /// The field or top-level variable associated with this property accessors.
+  ///
+  /// If this property accessor was explicitly defined (is not synthetic) then
+  /// the variable associated with it will be synthetic.
+  PropertyInducingFragment? get variable3;
+}
+
 /// A variable that has an associated getter and possibly a setter. Note that
 /// explicitly defined variables implicitly define a synthetic getter and that
 /// non-`final` explicitly defined variables implicitly define a synthetic
@@ -2180,7 +2209,7 @@ abstract class PropertyInducingFragment
 /// top-level variable or a field. Induced setters are synthetic.
 ///
 /// Clients may not extend, implement or mix-in this class.
-abstract class SetterElement implements ExecutableElement2 {
+abstract class SetterElement implements PropertyAccessorElement2 {
   @override
   SetterElement get baseElement;
 
@@ -2190,18 +2219,12 @@ abstract class SetterElement implements ExecutableElement2 {
 
   @override
   SetterFragment get firstFragment;
-
-  /// The field or top-level variable associated with this setter.
-  ///
-  /// If this setter was explicitly defined (is not synthetic) then the variable
-  /// associated with it will be synthetic.
-  PropertyInducingElement2? get variable3;
 }
 
 /// The portion of a [SetterElement] contributed by a single declaration.
 ///
 /// Clients may not extend, implement or mix-in this class.
-abstract class SetterFragment implements ExecutableFragment {
+abstract class SetterFragment implements PropertyAccessorFragment {
   /// The getter that corresponds to (has the same name as) this setter, or
   /// `null` if there is no corresponding getter.
   GetterFragment? get correspondingGetter2;
@@ -2222,12 +2245,6 @@ abstract class SetterFragment implements ExecutableFragment {
   //  setters.
   // @override
   // SetterFragment? get previousFragment;
-
-  /// The field or top-level variable associated with this setter.
-  ///
-  /// If this setter was explicitly defined (is not synthetic) then the variable
-  /// associated with it will be synthetic.
-  PropertyInducingFragment? get variable3;
 }
 
 /// A super formal parameter.