Augment. Use nullable PropertyAccessorElement.variable2

As much as I don't like the scale of changes, there is no valid variable in these cases. So, we express this explicitly, without trying to pretend that there is on. Or crashing as we did without this CL.

Change-Id: I74cef1d3d9d3cba6985d83b98be361cca09170f9
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/355300
Reviewed-by: Phil Quitslund <[email protected]>
Commit-Queue: Konstantin Shcheglov <[email protected]>

pkg/analysis_server/lib/src/cider/rename.dart

@@ -366,7 +366,10 @@ class CiderRenameComputer {
       return null;
     }
     if (element is PropertyAccessorElement) {
-      element = element.variable;
+      element = element.variable2;
+      if (element == null) {
+        return null;
+      }
     }
     if (!_canRenameElement(element)) {
       return null;

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

@@ -283,7 +283,7 @@ class DartUnitHighlightsComputer {
     }
     if (element is PropertyAccessorElement) {
       var accessor = element;
-      var variable = accessor.variable;
+      var variable = accessor.variable2;
       if (variable is TopLevelVariableElement) {
         type = accessor.isGetter
             ? HighlightRegionType.TOP_LEVEL_GETTER_REFERENCE

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

@@ -199,7 +199,7 @@ class _DartUnitOccurrencesComputerVisitor extends RecursiveAstVisitor<void> {
     if (canonicalElement is FieldFormalParameterElement) {
       canonicalElement = canonicalElement.field;
     } else if (canonicalElement is PropertyAccessorElement) {
-      canonicalElement = canonicalElement.variable;
+      canonicalElement = canonicalElement.variable2;
     }
     return canonicalElement?.declaration;
   }

pkg/analysis_server/lib/src/handler/legacy/search_find_element_references.dart

@@ -33,7 +33,7 @@ class SearchFindElementReferencesHandler extends LegacyHandler {
       element = element.field;
     }
     if (element is PropertyAccessorElement) {
-      element = element.variable;
+      element = element.variable2;
     }
     // respond
     var searchId = (server.nextSearchId++).toString();

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

@@ -174,11 +174,11 @@ class DefinitionHandler extends LspMessageHandler<TextDocumentPositionParams,
 
   /// Get the location of the code (excluding leading doc comments) for this element.
   Future<protocol.Location?> _getCodeLocation(Element element) async {
-    var codeElement = element;
+    Element? codeElement = element;
     // For synthetic getters created for fields, we need to access the associated
     // variable to get the codeOffset/codeLength.
-    if (codeElement.isSynthetic && codeElement is PropertyAccessorElementImpl) {
-      codeElement = codeElement.variable;
+    if (codeElement is PropertyAccessorElementImpl && codeElement.isSynthetic) {
+      codeElement = codeElement.variable2!;
     }
 
     // Read the main codeOffset from the element. This may include doc comments

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

@@ -201,7 +201,7 @@ class DocumentColorPresentationHandler extends SharedMessageHandler<
         ? parent.staticElement
         : node.staticElement;
     final target = staticElement is PropertyAccessorElement
-        ? staticElement.variable
+        ? staticElement.variable2
         : staticElement;
 
     final existingIsConst = target is ConstVariableElement;

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

@@ -184,7 +184,7 @@ class TypeDefinitionHandler extends SharedMessageHandler<TypeDefinitionParams,
       } else if (node.inSetterContext()) {
         final writeElement = node.writeElement;
         if (writeElement is PropertyAccessorElement) {
-          return writeElement.variable.type;
+          return writeElement.variable2?.type;
         }
       }
     }

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

@@ -1656,5 +1656,12 @@ extension on List<ExecutableElement> {
 
 extension on PropertyAccessorElement {
   /// Whether this accessor is an accessor for a constant variable.
-  bool get isConst => isSynthetic && variable.isConst;
+  bool get isConst {
+    if (isSynthetic) {
+      if (variable2 case var variable?) {
+        return variable.isConst;
+      }
+    }
+    return false;
+  }
 }

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

@@ -199,7 +199,11 @@ class FeatureComputer {
     } else if (element is FieldElement && element.isEnumConstant) {
       return protocol.ElementKind.ENUM_CONSTANT;
     } else if (element is PropertyAccessorElement) {
-      element = element.variable;
+      var variable = element.variable2;
+      if (variable == null) {
+        return protocol.ElementKind.UNKNOWN;
+      }
+      element = variable;
     }
     var kind = element.kind;
     if (kind == ElementKind.CONSTRUCTOR) {
@@ -314,11 +318,11 @@ class FeatureComputer {
       return 1.0;
     } else if (element is TopLevelVariableElement && element.isConst) {
       return 1.0;
-    } else if (element is PropertyAccessorElement &&
-        element.isSynthetic &&
-        element.variable.isStatic &&
-        element.variable.isConst) {
-      return 1.0;
+    } else if (element is PropertyAccessorElement && element.isSynthetic) {
+      var variable = element.variable2;
+      if (variable != null && variable.isStatic && variable.isConst) {
+        return 1.0;
+      }
     }
     return 0.0;
   }

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

@@ -124,8 +124,11 @@ class LibraryElementSuggestionBuilder extends GeneralizingElementVisitor<void> {
 
   @override
   void visitPropertyAccessorElement(PropertyAccessorElement element) {
+    var variable = element.variable2;
     if (opType.includeReturnValueSuggestions ||
-        (opType.includeAnnotationSuggestions && element.variable.isConst)) {
+        (opType.includeAnnotationSuggestions &&
+            variable != null &&
+            variable.isConst)) {
       var parent = element.enclosingElement;
       if (parent is InterfaceElement || parent is ExtensionElement) {
         builder.suggestAccessor(element, inheritanceDistance: 0.0);

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

@@ -89,7 +89,8 @@ class MemberSuggestionBuilder {
       {required PropertyAccessorElement accessor,
       required double inheritanceDistance}) {
     if (accessor.isAccessibleIn(request.libraryElement)) {
-      var member = accessor.isSynthetic ? accessor.variable : accessor;
+      var member =
+          accessor.isSynthetic ? accessor.variable2 ?? accessor : accessor;
       if (_shouldAddSuggestion(member)) {
         builder.suggestAccessor(accessor,
             inheritanceDistance: inheritanceDistance);
@@ -269,7 +270,7 @@ class SuggestionBuilder {
       // non-final fields induce a setter, so we don't add a suggestion for a
       // synthetic setter.
       if (accessor.isGetter) {
-        var variable = accessor.variable;
+        var variable = accessor.variable2;
         if (variable is FieldElement) {
           suggestField(variable, inheritanceDistance: inheritanceDistance);
         }
@@ -1145,7 +1146,7 @@ class SuggestionBuilder {
       // non-final fields induce a setter, so we don't add a suggestion for a
       // synthetic setter.
       if (accessor.isGetter) {
-        var variable = accessor.variable;
+        var variable = accessor.variable2;
         if (variable is TopLevelVariableElement) {
           suggestTopLevelVariable(variable);
         }

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

@@ -30,7 +30,7 @@ class AddLate extends ResolvedCorrectionProducer {
               await _insertAt(builder, variableList.variables[0].offset);
               // TODO(brianwilkerson): Consider converting this into an assist and
               //  expand it to support converting `var` to `late` as well as
-              //  working anywhere a non-late local variable or field is selected.
+              //  working anywhere a non-late local variableElement or field is selected.
 //          } else if (keyword.type == Keyword.VAR) {
 //            builder.addFileEdit(file, (builder) {
 //              builder.addSimpleReplacement(range.token(keyword), 'late');
@@ -56,26 +56,29 @@ class AddLate extends ResolvedCorrectionProducer {
       if (getter is PropertyAccessorElement &&
           getter.isGetter &&
           getter.isSynthetic &&
-          !getter.variable.isSynthetic &&
-          !getter.variable.isLate &&
-          getter.variable.setter == null &&
           getter.enclosingElement is InterfaceElement) {
-        var declarationResult =
-            await sessionHelper.getElementDeclaration(getter.variable);
-        if (declarationResult == null) {
-          return;
-        }
-        var variable = declarationResult.node;
-        var variableList = variable.parent;
-        if (variable is VariableDeclaration &&
-            variableList is VariableDeclarationList &&
-            variableList.parent is FieldDeclaration) {
-          var keywordToken = variableList.keyword;
-          if (variableList.variables.length == 1 &&
-              keywordToken != null &&
-              keywordToken.keyword == Keyword.FINAL) {
-            await _insertAt(builder, keywordToken.offset,
-                source: declarationResult.element.source);
+        var variableElement = getter.variable2;
+        if (variableElement != null &&
+            !variableElement.isSynthetic &&
+            !variableElement.isLate &&
+            variableElement.setter == null) {
+          var declarationResult =
+              await sessionHelper.getElementDeclaration(variableElement);
+          if (declarationResult == null) {
+            return;
+          }
+          var variableNode = declarationResult.node;
+          var variableList = variableNode.parent;
+          if (variableNode is VariableDeclaration &&
+              variableList is VariableDeclarationList &&
+              variableList.parent is FieldDeclaration) {
+            var keywordToken = variableList.keyword;
+            if (variableList.variables.length == 1 &&
+                keywordToken != null &&
+                keywordToken.keyword == Keyword.FINAL) {
+              await _insertAt(builder, keywordToken.offset,
+                  source: declarationResult.element.source);
+            }
           }
         }
       }

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

@@ -286,7 +286,7 @@ class _FieldFinder extends RecursiveAstVisitor<void> {
     if (node.inSetterContext()) {
       var element = node.writeOrReadElement;
       if (element is PropertyAccessorElement) {
-        var field = element.variable;
+        var field = element.variable2;
         if (field is FieldElement) {
           fieldsAssignedInConstructors.add(field);
         }

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

@@ -286,7 +286,7 @@ class _FieldFinder extends RecursiveAstVisitor<void> {
     if (node.inSetterContext()) {
       var element = node.writeOrReadElement;
       if (element is PropertyAccessorElement) {
-        var field = element.variable;
+        var field = element.variable2;
         if (field is FieldElement) {
           fieldsAssignedInConstructors.add(field);
         }

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

@@ -259,7 +259,10 @@ class ImportLibrary extends MultiCorrectionProducer {
         continue;
       }
       if (element is PropertyAccessorElement) {
-        element = element.variable;
+        element = element.variable2;
+        if (element == null) {
+          continue;
+        }
       }
       if (!kinds.contains(element.kind)) {
         continue;

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

@@ -39,7 +39,10 @@ class MakeFieldNotFinal extends ResolvedCorrectionProducer {
     }
 
     // The variable must be not synthetic, and have no setter yet.
-    var variable = getter.variable;
+    var variable = getter.variable2;
+    if (variable == null) {
+      return;
+    }
     if (variable.isSynthetic || variable.setter != null) {
       return;
     }

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

@@ -278,7 +278,7 @@ class _ElementReferenceCollector extends RecursiveAstVisitor<void> {
     if (staticElement == element) {
       references.add(node);
     } else if (staticElement is PropertyAccessorElement) {
-      if (staticElement.variable == element) {
+      if (staticElement.variable2 == element) {
         references.add(node);
       }
     } else if (staticElement is FieldFormalParameterElement) {

pkg/analysis_server/lib/src/services/flutter/widget_descriptions.dart

@@ -542,7 +542,7 @@ class _WidgetDescriptionComputer {
     } else if (valueExpression is Identifier) {
       var element = valueExpression.staticElement;
       if (element is PropertyAccessorElement && element.isGetter) {
-        var field = element.variable;
+        var field = element.variable2;
         if (field is FieldElement && field.isStatic) {
           var enclosingClass = field.enclosingElement as InterfaceElement;
           if (field.isEnumConstant ||

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

@@ -54,7 +54,7 @@ class ConvertGetterToMethodRefactoringImpl extends RefactoringImpl
       await _updateElementReferences(element);
     }
     // method
-    var field = element.variable;
+    var field = element.variable2;
     if (field is FieldElement &&
         (field.enclosingElement is InterfaceElement ||
             field.enclosingElement is ExtensionElement)) {

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

@@ -629,7 +629,10 @@ class _ParametersCollector extends RecursiveAstVisitor<void> {
         }
       }
     } else if (element is PropertyAccessorElement) {
-      var field = element.variable;
+      var field = element.variable2;
+      if (field == null) {
+        return;
+      }
       if (_isMemberOfEnclosingClass(field)) {
         if (node.inSetterContext()) {
           status.addError("Write to '$elementName' cannot be extracted.");

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

@@ -416,7 +416,10 @@ abstract class RenameRefactoring implements Refactoring {
     var session = resolvedUnit.session;
     var sessionHelper = AnalysisSessionHelper(session);
     if (element is PropertyAccessorElement) {
-      element = element.variable;
+      element = element.variable2;
+      if (element == null) {
+        return null;
+      }
     }
     var enclosingElement = element.enclosingElement;
     if (enclosingElement is CompilationUnitElement) {

pkg/analysis_server/lib/src/services/search/hierarchy.dart

@@ -191,7 +191,7 @@ List<Element> getMembers(InterfaceElement clazz) {
 Element getSyntheticAccessorVariable(Element element) {
   if (element is PropertyAccessorElement) {
     if (element.isSynthetic) {
-      return element.variable;
+      return element.variable2 ?? element;
     }
   }
   return element;

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

@@ -111,7 +111,11 @@ class _ElementRecorder {
       LibraryImportElement? import) {
     if (referencedElement is PropertyAccessorElement &&
         referencedElement.isSynthetic) {
-      referencedElement = referencedElement.variable;
+      var variable = referencedElement.variable2;
+      if (variable == null) {
+        return;
+      }
+      referencedElement = variable;
     }
     if (_isBeingMoved(referenceOffset)) {
       var imports =

pkg/analyzer/CHANGELOG.md

@@ -5,6 +5,10 @@
 * Deprecated `InterfaceElement.lookUpGetter`, `InterfaceElement.lookUpMethod`,
   and `InterfaceElement.lookUpSetter`.
 * Fixed `GeneralizingAstVisitor.visitNamedType` to invoke `visitTypeAnnotation`.
+* Deprecated `PropertyInducingElement get variable` in `PropertyAccessorElement`,
+  use `PropertyInducingElement? get variable2` instead.
+  The reason for this is that when the property accessor is an augmentation
+  without the corresponding declaration, there is no corresponding variable.
 
 ## 6.4.1
 * Patch for crash in ffi_verifier.

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

@@ -2341,7 +2341,17 @@ abstract class PropertyAccessorElement implements ExecutableElement {
   ///
   /// If this accessor was explicitly defined (is not synthetic) then the
   /// variable associated with it will be synthetic.
+  @Deprecated('Use variable2')
   PropertyInducingElement get variable;
+
+  /// The field or top-level variable associated with this accessor.
+  ///
+  /// If this accessor was explicitly defined (is not synthetic) then the
+  /// variable associated with it will be synthetic.
+  ///
+  /// If this accessor is an augmentation, and [augmentationTarget] is `null`,
+  /// the variable is `null`.
+  PropertyInducingElement? get variable2;
 }
 
 /// A variable that has an associated getter and possibly a setter. Note that

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

@@ -164,7 +164,9 @@ class IndexElementInfo {
           kind = accessor.isGetter
               ? IndexSyntheticElementKind.getter
               : IndexSyntheticElementKind.setter;
-          element = accessor.variable;
+          if (accessor.variable2 case var variable?) {
+            element = variable;
+          }
         }
       } else if (element is MethodElement) {
         Element enclosing = element.enclosingElement;