Fine. Update PreferIsNotEmpty to use getGetter() instead of requesting all children.

Replace child enumeration with a targeted member lookup in the
`prefer_is_not_empty` rule. Instead of requesting all children to check
for `isNotEmpty`, the rule now calls `InterfaceElement.getGetter()` on
the declaring interface of `isEmpty`. This avoids recording an "opaque
API use" requirement and reduces unnecessary dependency tracking and
overhead.

Additionally, remove generic child-walking utilities from `ast.dart`
that were only used for this purpose.

Changes:
- In `prefer_is_not_empty.dart`, use
  `InterfaceElement.getGetter('isNotEmpty')` instead of `getChildren`.
- Drop `getChildren`, `_visitChildren`, `ElementProcessor`, and the
  visitor adapter from `ast.dart`, along with their imports.
- Remove the unused `../ast.dart` import from the rule and add the
  precise `element.dart` import.

No functional changes to the lint’s intent: it still recommends
`isNotEmpty` for `Iterable` and `Map` types, but does so without walking
children, improving precision and performance of fine-grained tracking.

Found with https://dart-review.googlesource.com/c/sdk/+/446480

Change-Id: I1e0e9991aeba924b672d1216bed2669215ab20cd
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/446580
Reviewed-by: Brian Wilkerson <[email protected]>
Commit-Queue: Konstantin Shcheglov <[email protected]>

Author: scheglov

pkg/linter/lib/src/ast.dart

@@ -10,23 +10,10 @@ import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/ast/syntactic_entity.dart';
 import 'package:analyzer/dart/ast/token.dart';
 import 'package:analyzer/dart/element/element.dart';
-import 'package:analyzer/dart/element/visitor2.dart';
 import 'package:analyzer/file_system/file_system.dart';
 import 'package:analyzer/workspace/workspace.dart';
 import 'package:path/path.dart' as path;
 
-/// Returns direct children of [parent].
-List<Element> getChildren(Element parent, [String? name]) {
-  var children = <Element>[];
-  _visitChildren(parent, (Element element) {
-    if (name == null || element.displayName == name) {
-      children.add(element);
-    }
-    return false;
-  });
-  return children;
-}
-
 /// Return the compilation unit of a node
 CompilationUnit? getCompilationUnit(AstNode node) =>
     node.thisOrAncestorOfType<CompilationUnit>();
@@ -343,31 +330,6 @@ bool _hasFieldOrMethod(ClassMember element, String name) =>
     (element is MethodDeclaration && element.name.lexeme == name) ||
     (element is FieldDeclaration && getFieldName(element, name) != null);
 
-/// Uses [processor] to visit all of the children of [element].
-/// If [processor] returns `true`, then children of a child are visited too.
-void _visitChildren(Element element, ElementProcessor processor) {
-  element.visitChildren(_ElementVisitorAdapter(processor));
-}
-
-/// An [Element] processor function type.
-/// If `true` is returned, children of [element] will be visited.
-typedef ElementProcessor = bool Function(Element element);
-
-/// A [GeneralizingElementVisitor2] adapter for [ElementProcessor].
-class _ElementVisitorAdapter extends GeneralizingElementVisitor2<void> {
-  final ElementProcessor processor;
-
-  _ElementVisitorAdapter(this.processor);
-
-  @override
-  void visitElement(Element element) {
-    var visitChildren = processor(element);
-    if (visitChildren) {
-      element.visitChildren(this);
-    }
-  }
-}
-
 extension AstNodeExtension on AstNode {
   bool get isToStringInvocationWithArguments {
     var self = this;

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

@@ -8,10 +8,10 @@ import 'package:analyzer/dart/ast/ast.dart'
     show PrefixExpression, PrefixedIdentifier, PropertyAccess, SimpleIdentifier;
 import 'package:analyzer/dart/ast/token.dart';
 import 'package:analyzer/dart/ast/visitor.dart';
+import 'package:analyzer/dart/element/element.dart';
 import 'package:analyzer/error/error.dart';
 
 import '../analyzer.dart';
-import '../ast.dart';
 
 const _desc = r'Use `isNotEmpty` for `Iterable`s and `Map`s.';
 
@@ -66,8 +66,8 @@ class _Visitor extends SimpleAstVisitor<void> {
 
     // Element should also support "isNotEmpty".
     var propertyTarget = propertyElement.enclosingElement;
-    if (propertyTarget == null ||
-        getChildren(propertyTarget, 'isNotEmpty').isEmpty) {
+    if (propertyTarget is! InterfaceElement ||
+        propertyTarget.getGetter('isNotEmpty') == null) {
       return;
     }