linter: Simplify code that uses the "write or read element"

Change-Id: I565ce698939c34be0c32dbc0c0204dd6b962fe1d
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/503141
Commit-Queue: Samuel Rawlins <srawlins@google.com>
Reviewed-by: Keerti Parthasarathy <keertip@google.com>

pkg/linter/lib/src/ast.dart

@@ -91,12 +91,6 @@ SyntacticEntity getNodeToAnnotate(AstNode node) {
   return node;
 }
 
-/// If the [node] is the finishing identifier of an assignment, return its
-/// "writeElement", otherwise return its "element", which might be
-/// thought as the "readElement".
-Element? getWriteOrReadElement(SimpleIdentifier node) =>
-    _getWriteElement(node) ?? node.element;
-
 bool hasConstantError(Expression node) =>
     node.computeConstantValue()?.diagnostics.isNotEmpty ?? true;
 
@@ -293,33 +287,6 @@ int? _getIntValue(
   return negated ? -value : value;
 }
 
-/// If the [node] is the target of a [CompoundAssignmentExpression],
-/// return the corresponding "writeElement", which is the local variable,
-/// the setter referenced with a [SimpleIdentifier] or a [PropertyAccess],
-/// or the `[]=` operator.
-Element? _getWriteElement(AstNode node) {
-  var parent = node.parent;
-  if (parent is AssignmentExpression && parent.leftHandSide == node) {
-    return parent.writeElement;
-  }
-  if (parent is PostfixExpression) {
-    return parent.writeElement;
-  }
-  if (parent is PrefixExpression) {
-    return parent.writeElement;
-  }
-
-  if (parent is PrefixedIdentifier && parent.identifier == node) {
-    return _getWriteElement(parent);
-  }
-
-  if (parent is PropertyAccess && parent.propertyName == node) {
-    return _getWriteElement(parent);
-  }
-
-  return null;
-}
-
 bool _hasFieldOrMethod(ClassMember element, String name) =>
     (element is MethodDeclaration && element.name.lexeme == name) ||
     (element is FieldDeclaration && getFieldName(element, name) != null);

pkg/linter/lib/src/rules/prefer_asserts_in_initializer_lists.dart

@@ -9,9 +9,9 @@ import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/ast/visitor.dart';
 import 'package:analyzer/dart/element/element.dart';
 import 'package:analyzer/error/error.dart';
+import 'package:analyzer/src/dart/ast/extensions.dart'; // ignore: implementation_imports
 
 import '../analyzer.dart';
-import '../ast.dart';
 import '../diagnostic.dart' as diag;
 
 const _desc = r'Prefer putting asserts in initializer lists.';
@@ -48,7 +48,7 @@ class _AssertVisitor extends RecursiveAstVisitor<void> {
 
   @override
   void visitSimpleIdentifier(SimpleIdentifier node) {
-    var element = getWriteOrReadElement(node);
+    var element = node.writeOrReadElement;
 
     // use method
     needInstance =

pkg/linter/lib/src/rules/unnecessary_this.dart

@@ -9,9 +9,9 @@ import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/ast/visitor.dart';
 import 'package:analyzer/dart/element/element.dart';
 import 'package:analyzer/error/error.dart';
+import 'package:analyzer/src/dart/ast/extensions.dart'; // ignore: implementation_imports
 
 import '../analyzer.dart';
-import '../ast.dart';
 import '../diagnostic.dart' as diag;
 import '../util/scope.dart';
 
@@ -56,7 +56,7 @@ class _Visitor extends SimpleAstVisitor<void> {
 
     Element? element;
     if (parent is PropertyAccess && !parent.isNullAware) {
-      element = getWriteOrReadElement(parent.propertyName);
+      element = parent.propertyName.writeOrReadElement;
     } else if (parent is MethodInvocation && !parent.isNullAware) {
       element = parent.methodName.element;
     } else {

pkg/linter/lib/src/util/dart_type_utilities.dart

@@ -6,8 +6,8 @@ import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/element/element.dart';
 import 'package:analyzer/dart/element/type.dart';
 import 'package:analyzer/dart/element/type_system.dart';
+import 'package:analyzer/src/dart/ast/extensions.dart'; // ignore: implementation_imports
 
-import '../ast.dart';
 import '../extensions.dart';
 
 bool argumentsMatchParameters(
@@ -105,8 +105,8 @@ bool canonicalElementsFromIdentifiersAreEqual(
   if (expression1 is SimpleIdentifier) {
     return expression2 is SimpleIdentifier &&
         canonicalElementsAreEqual(
-          getWriteOrReadElement(expression1),
-          getWriteOrReadElement(expression2),
+          expression1.writeOrReadElement,
+          expression2.writeOrReadElement,
         );
   }
 
@@ -117,8 +117,8 @@ bool canonicalElementsFromIdentifiersAreEqual(
           expression2.prefix.element,
         ) &&
         canonicalElementsAreEqual(
-          getWriteOrReadElement(expression1.identifier),
-          getWriteOrReadElement(expression2.identifier),
+          expression1.identifier.writeOrReadElement,
+          expression2.identifier.writeOrReadElement,
         );
   }
 
@@ -127,8 +127,8 @@ bool canonicalElementsFromIdentifiersAreEqual(
     var target2 = expression2.target;
     return canonicalElementsFromIdentifiersAreEqual(target1, target2) &&
         canonicalElementsAreEqual(
-          getWriteOrReadElement(expression1.propertyName),
-          getWriteOrReadElement(expression2.propertyName),
+          expression1.propertyName.writeOrReadElement,
+          expression2.propertyName.writeOrReadElement,
         );
   }