[element model] migrate library_annotations

Bug: https://github.com/dart-lang/linter/issues/5099
Change-Id: I386be7cbd2768d031ab42cc47d5b007e1f6d8478
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/389360
Reviewed-by: Konstantin Shcheglov <[email protected]>
Reviewed-by: Brian Wilkerson <[email protected]>
Commit-Queue: Phil Quitslund <[email protected]>

Author: pq

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

@@ -897,6 +897,16 @@ abstract class ElementAnnotation implements ConstantEvaluationTarget {
   /// other element.
   Element? get element;
 
+  /// Returns the element referenced by this annotation.
+  ///
+  /// In valid code this element can be a [GetterElement] of a constant
+  /// top-level variable, or a constant static field of a class; or a
+  /// constant [ConstructorElement].
+  ///
+  /// In invalid code this element can be `null`, or a reference to any
+  /// other element.
+  Element2? get element2;
+
   /// Whether the annotation marks the associated function as always throwing.
   bool get isAlwaysThrows;
 

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

@@ -2078,6 +2078,11 @@ class ElementAnnotationImpl implements ElementAnnotation {
   @override
   AnalysisContext get context => compilationUnit.library.context;
 
+  @override
+  Element2? get element2 {
+    return element?.asElement2;
+  }
+
   @override
   bool get isAlwaysThrows => _isPackageMetaGetter(_alwaysThrowsVariableName);
 

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

@@ -4,7 +4,7 @@
 
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/ast/visitor.dart';
-import 'package:analyzer/dart/element/element.dart';
+import 'package:analyzer/dart/element/element2.dart';
 // ignore: implementation_imports
 import 'package:analyzer/src/dart/element/extensions.dart';
 import 'package:meta/meta_meta.dart';
@@ -89,9 +89,9 @@ extension on ElementAnnotation {
     required String libraryName,
     required String className,
   }) {
-    var element = this.element;
-    return element is ConstructorElement &&
-        element.enclosingElement3.name == className &&
-        element.library.name == libraryName;
+    var element = element2;
+    return element is ConstructorElement2 &&
+        element.enclosingElement2.name == className &&
+        element.library2?.name == libraryName;
   }
 }