Address comments

Author: keertip

lib/src/model/library.dart

@@ -10,7 +10,7 @@ import 'package:analyzer/dart/element/element2.dart';
 import 'package:analyzer/dart/element/scope.dart';
 import 'package:analyzer/source/line_info.dart';
 // ignore: implementation_imports
-import 'package:analyzer/src/dart/element/element.dart';
+import 'package:analyzer/src/utilities/extensions/element.dart';
 // ignore: implementation_imports
 import 'package:dartdoc/src/model/comment_referable.dart';
 import 'package:dartdoc/src/model/kind.dart';
@@ -30,7 +30,7 @@ class Library extends ModelElement
   final LibraryElement element;
 
   @override
-   LibraryElement2 get element2 => element as LibraryElementImpl;
+   LibraryElement2 get element2 => element.asElement2;
 
   /// The set of [Element]s declared directly in this library.
   final Set<Element> _localElements;
@@ -316,7 +316,7 @@ class Library extends ModelElement
 
   /// The real packageMeta, as opposed to the package we are documenting with.
   late final PackageMeta? packageMeta =
-      packageGraph.packageMetaProvider.fromElement(element as LibraryElementImpl, config.sdkDir);
+      packageGraph.packageMetaProvider.fromElement(element.asElement2, config.sdkDir);
 
   late final List<Class> classesAndExceptions = [
     ..._localElementsOfType<ClassElement, Class>(),

lib/src/warnings.dart

@@ -506,7 +506,7 @@ class PackageWarningCounter {
   UnmodifiableMapView<Element2?, Map<PackageWarning, Set<String>>>
       get countedWarnings2 => UnmodifiableMapView(_countedWarnings.map((key,
               value) =>
-          MapEntry(key != null ? (key.asElement2 as Element2) : null, value)));
+          MapEntry(key?.asElement2, value)));
 
   PackageWarningCounter(this.packageGraph);