Elements. Deprecate V1 element visitors.

Change-Id: I51a19c20bfed38a92e6faba561949225a6d1d7a8
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/413840
Reviewed-by: Brian Wilkerson <[email protected]>
Commit-Queue: Konstantin Shcheglov <[email protected]>
Reviewed-by: Paul Berry <[email protected]>

Author: scheglov

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

@@ -3,7 +3,6 @@
 // BSD-style license that can be found in the LICENSE file.
 
 import 'package:analyzer/dart/element/element2.dart';
-import 'package:analyzer/dart/element/visitor.dart';
 import 'package:analyzer/dart/element/visitor2.dart';
 
 /// Returns the fragment that is either [fragment], or one of its direct or
@@ -22,7 +21,7 @@ void visitChildren(Element2 element, BoolElementProcessor processor) {
 /// If `true` is returned, children of [element] will be visited.
 typedef BoolElementProcessor = bool Function(Element2 element);
 
-/// A [GeneralizingElementVisitor] adapter for [BoolElementProcessor].
+/// A [GeneralizingElementVisitor2] adapter for [BoolElementProcessor].
 class _ElementVisitorAdapter extends GeneralizingElementVisitor2<void> {
   final BoolElementProcessor processor;
 

pkg/analyzer/api.txt

@@ -3171,15 +3171,15 @@ package:analyzer/dart/element/element.dart:
     session (getter: AnalysisSession?)
     sinceSdkVersion (getter: Version?)
     source (getter: Source?)
-    accept (method: T? Function<T>(ElementVisitor<T>))
+    accept (method: T? Function<T>(ElementVisitor<T>), deprecated)
     getDisplayString (method: String Function({bool multiline, bool withNullability}))
     getExtendedDisplayName (method: String Function(String?))
     isAccessibleIn (method: bool Function(LibraryElement))
     thisOrAncestorMatching (method: E? Function<E extends Element>(bool Function(Element)))
     thisOrAncestorMatching3 (method: E? Function<E extends Element>(bool Function(Element)))
     thisOrAncestorOfType (method: E? Function<E extends Element>())
     thisOrAncestorOfType3 (method: E? Function<E extends Element>())
-    visitChildren (method: void Function(ElementVisitor<dynamic>))
+    visitChildren (method: void Function(ElementVisitor<dynamic>), deprecated)
   ElementAnnotation (class extends Object implements ConstantEvaluationTarget):
     new (constructor: ElementAnnotation Function())
     constantEvaluationErrors (getter: List<AnalysisError>?)
@@ -3264,7 +3264,7 @@ package:analyzer/dart/element/element.dart:
     new (constructor: ElementLocation Function())
     components (getter: List<String>)
     encoding (getter: String)
-  ElementVisitor (class<R> extends Object):
+  ElementVisitor (class<R> extends Object, deprecated):
     new (constructor: ElementVisitor<R> Function())
     visitClassElement (method: R? Function(ClassElement))
     visitCompilationUnitElement (method: R? Function(CompilationUnitElement))
@@ -4620,7 +4620,7 @@ package:analyzer/dart/element/type_visitor.dart:
     visitTypeParameterType (method: R Function(TypeParameterType, A))
     visitVoidType (method: R Function(VoidType, A))
 package:analyzer/dart/element/visitor.dart:
-  GeneralizingElementVisitor (class<R> extends Object implements ElementVisitor<R>):
+  GeneralizingElementVisitor (class<R> extends Object implements ElementVisitor<R>, deprecated):
     new (constructor: GeneralizingElementVisitor<R> Function())
     visitClassElement (method: R? Function(ClassElement))
     visitCompilationUnitElement (method: R? Function(CompilationUnitElement))
@@ -4653,7 +4653,7 @@ package:analyzer/dart/element/visitor.dart:
     visitTypeAliasElement (method: R? Function(TypeAliasElement))
     visitTypeParameterElement (method: R? Function(TypeParameterElement))
     visitVariableElement (method: R? Function(VariableElement))
-  RecursiveElementVisitor (class<R> extends Object implements ElementVisitor<R>):
+  RecursiveElementVisitor (class<R> extends Object implements ElementVisitor<R>, deprecated):
     new (constructor: RecursiveElementVisitor<R> Function())
     visitClassElement (method: R? Function(ClassElement))
     visitCompilationUnitElement (method: R? Function(CompilationUnitElement))
@@ -4681,7 +4681,7 @@ package:analyzer/dart/element/visitor.dart:
     visitTopLevelVariableElement (method: R? Function(TopLevelVariableElement))
     visitTypeAliasElement (method: R? Function(TypeAliasElement))
     visitTypeParameterElement (method: R? Function(TypeParameterElement))
-  SimpleElementVisitor (class<R> extends Object implements ElementVisitor<R>):
+  SimpleElementVisitor (class<R> extends Object implements ElementVisitor<R>, deprecated):
     new (constructor: SimpleElementVisitor<R> Function())
     visitClassElement (method: R? Function(ClassElement))
     visitCompilationUnitElement (method: R? Function(CompilationUnitElement))
@@ -4709,7 +4709,7 @@ package:analyzer/dart/element/visitor.dart:
     visitTopLevelVariableElement (method: R? Function(TopLevelVariableElement))
     visitTypeAliasElement (method: R? Function(TypeAliasElement))
     visitTypeParameterElement (method: R? Function(TypeParameterElement))
-  ThrowingElementVisitor (class<R> extends Object implements ElementVisitor<R>):
+  ThrowingElementVisitor (class<R> extends Object implements ElementVisitor<R>, deprecated):
     new (constructor: ThrowingElementVisitor<R> Function())
     visitClassElement (method: R? Function(ClassElement))
     visitCompilationUnitElement (method: R? Function(CompilationUnitElement))

pkg/analyzer/doc/tutorial/element.md

@@ -135,12 +135,12 @@ parameters). Hence, you'd want to create a subclass of
 `GeneralizingElementVisitor`.
 
 ```dart
-class ParameterCounter extends GeneralizingElementVisitor<void> {
+class ParameterCounter extends GeneralizingElementVisitor2<void> {
   int maxParameterCount = 0;
 
   @override
-  void visitExecutableElement(ExecutableElement element) {
-    maxParameterCount = math.max(maxParameterCount, element.parameters.length);
+  void visitExecutableElement(ExecutableElement2 element) {
+    maxParameterCount = math.max(maxParameterCount, element.formalParameters.length);
     super.visitExecutableElement(element);
   }
 }

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

@@ -797,6 +797,7 @@ abstract class Element implements AnalysisTarget {
   ///
   /// Returns the value returned by the visitor as a result of visiting this
   /// element.
+  @Deprecated('Use Element2 and accept2() instead')
   T? accept<T>(ElementVisitor<T> visitor);
 
   /// Returns the presentation of this element as it should appear when
@@ -862,6 +863,7 @@ abstract class Element implements AnalysisTarget {
 
   /// Uses the given [visitor] to visit all of the children of this element.
   /// There is no guarantee of the order in which the children will be visited.
+  @Deprecated('Use Element2 and visitChildren2() instead')
   void visitChildren(ElementVisitor visitor);
 }
 
@@ -1194,6 +1196,7 @@ abstract class ElementLocation {
 ///   visited, and
 /// * ThrowingElementVisitor which implements every visit method by throwing an
 ///   exception.
+@Deprecated('Use ElementVisitor2 instead')
 abstract class ElementVisitor<R> {
   R? visitClassElement(ClassElement element);
 

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

@@ -2,16 +2,14 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// ignore_for_file: analyzer_use_new_elements
-
 /// Defines element visitors that support useful patterns for visiting the
 /// elements in an [element model](element.dart).
 ///
 /// Dart is an evolving language, and the element model must evolved with it.
 /// When the element model changes, the visitor interface will sometimes change
 /// as well. If it is desirable to get a compilation error when the structure of
 /// the element model has been modified, then you should consider implementing
-/// the interface [ElementVisitor] directly. Doing so will ensure that changes
+/// the interface `ElementVisitor` directly. Doing so will ensure that changes
 /// that introduce new classes of elements will be flagged. (Of course, not all
 /// changes to the element model require the addition of a new class of element,
 /// and hence cannot be caught this way.)
@@ -20,7 +18,7 @@
 /// you will probably want to extend one of the classes in this library because
 /// doing so will simplify the task of writing your visitor and guard against
 /// future changes to the element model. For example, the
-/// [RecursiveElementVisitor] automates the process of visiting all of the
+/// `RecursiveElementVisitor` automates the process of visiting all of the
 /// descendants of an element.
 library;
 
@@ -82,6 +80,7 @@ import 'package:analyzer/dart/element/element.dart';
 /// invoked and will cause the children of the visited node to not be visited.
 ///
 /// Clients may extend this class.
+@Deprecated('Use Element2, ElementVisitor2, and accept2() instead')
 class GeneralizingElementVisitor<R> implements ElementVisitor<R> {
   /// Initialize a newly created visitor.
   const GeneralizingElementVisitor();
@@ -216,6 +215,7 @@ class GeneralizingElementVisitor<R> implements ElementVisitor<R> {
 /// not be visited.
 ///
 /// Clients may extend this class.
+@Deprecated('Use Element2, ElementVisitor2, and accept2() instead')
 class RecursiveElementVisitor<R> implements ElementVisitor<R> {
   /// Initialize a newly created visitor.
   const RecursiveElementVisitor();
@@ -383,6 +383,7 @@ class RecursiveElementVisitor<R> implements ElementVisitor<R> {
 /// structure) and that only need to visit a small number of element types.
 ///
 /// Clients may extend this class.
+@Deprecated('Use Element2, ElementVisitor2, and accept2() instead')
 class SimpleElementVisitor<R> implements ElementVisitor<R> {
   /// Initialize a newly created visitor.
   const SimpleElementVisitor();
@@ -476,6 +477,7 @@ class SimpleElementVisitor<R> implements ElementVisitor<R> {
 /// want to catch when any other visit methods have been invoked.
 ///
 /// Clients may extend this class.
+@Deprecated('Use Element2, ElementVisitor2, and accept2() instead')
 class ThrowingElementVisitor<R> implements ElementVisitor<R> {
   /// Initialize a newly created visitor.
   const ThrowingElementVisitor();

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

@@ -6,7 +6,6 @@ import 'package:analyzer/dart/analysis/results.dart';
 import 'package:analyzer/dart/ast/syntactic_entity.dart';
 import 'package:analyzer/dart/ast/visitor.dart';
 import 'package:analyzer/dart/element/element2.dart';
-import 'package:analyzer/dart/element/visitor.dart';
 import 'package:analyzer/source/line_info.dart';
 import 'package:analyzer/source/source_range.dart';
 import 'package:analyzer/src/dart/analysis/driver.dart';
@@ -27,15 +26,30 @@ Fragment _getEnclosingFragment(
   CompilationUnitElementImpl libraryFragment,
   int offset,
 ) {
-  var finder = _ContainingFragmentFinder(offset);
-  libraryFragment.accept(finder);
-  var result = finder.containingFragment;
-  if (result == null) {
-    throw StateError(
-      'No containing fragment in ${libraryFragment.source.fullName} at $offset',
-    );
+  Fragment? visitFragment(Fragment fragment) {
+    var fragmentImpl = fragment as ElementImpl;
+    var codeOffset = fragmentImpl.codeOffset;
+    var codeLength = fragmentImpl.codeLength;
+    if (codeOffset == null || codeLength == null) {
+      return null;
+    }
+
+    var codeEnd = codeOffset + codeLength;
+    if (codeOffset <= offset && offset <= codeEnd) {
+      for (var child in fragment.children3) {
+        var result = visitFragment(child);
+        if (result != null) {
+          return result;
+        }
+      }
+      return fragment;
+    }
+
+    return null;
   }
-  return result;
+
+  var result = visitFragment(libraryFragment);
+  return result ?? libraryFragment;
 }
 
 DeclarationKind? _getSearchElementKind(Element2 element) {
@@ -1090,24 +1104,6 @@ class WorkspaceSymbols {
   }
 }
 
-/// A visitor that finds the deep-most [ElementImpl] that contains the [offset].
-class _ContainingFragmentFinder extends GeneralizingElementVisitor<void> {
-  final int offset;
-  Fragment? containingFragment;
-
-  _ContainingFragmentFinder(this.offset);
-
-  @override
-  void visitElement(covariant ElementImpl element) {
-    if (element.codeOffset != null &&
-        element.codeOffset! <= offset &&
-        offset <= element.codeOffset! + element.codeLength!) {
-      containingFragment = element as Fragment;
-      super.visitElement(element);
-    }
-  }
-}
-
 /// Searches through [fileEntries] for declarations.
 class _FindDeclarations {
   final List<MapEntry<Uri, AnalysisDriver>> fileEntries;