Elements. Make FragmentImpl.libraryFragment return type LibraryFragmentImpl.

Change-Id: Idfc1277dd0301c7de5e8a08b976f8ff78b2e59be
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/445604
Reviewed-by: Paul Berry <[email protected]>
Commit-Queue: Konstantin Shcheglov <[email protected]>

Author: scheglov

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

@@ -3268,7 +3268,7 @@ class FormalParameterFragmentImpl extends VariableFragmentImpl
   bool get isSuperFormal => false;
 
   @override
-  LibraryFragment? get libraryFragment {
+  LibraryFragmentImpl? get libraryFragment {
     return enclosingFragment?.libraryFragment;
   }
 
@@ -3391,6 +3391,9 @@ abstract class FragmentImpl with _FragmentImplMixin implements Fragment {
   /// in which they are declared.
   bool get isPublic => !isPrivate;
 
+  @override
+  LibraryFragmentImpl? get libraryFragment;
+
   String? get lookupName {
     return name;
   }
@@ -6299,7 +6302,7 @@ class LibraryFragmentImpl extends FragmentImpl
   List<LibraryExport> get libraryExports2 => libraryExports;
 
   @override
-  LibraryFragment get libraryFragment => this;
+  LibraryFragmentImpl get libraryFragment => this;
 
   @override
   List<LibraryImportImpl> get libraryImports {
@@ -8698,7 +8701,7 @@ abstract class PropertyInducingFragmentImpl
   }
 
   @override
-  LibraryFragment get libraryFragment {
+  LibraryFragmentImpl get libraryFragment {
     return enclosingFragment.libraryFragment!;
   }
 
@@ -9899,7 +9902,7 @@ class TypeParameterFragmentImpl extends FragmentImpl
   }
 
   @override
-  LibraryFragment? get libraryFragment {
+  LibraryFragmentImpl? get libraryFragment {
     return enclosingFragment?.libraryFragment;
   }
 

pkg/analyzer/lib/src/summary2/top_level_inference.dart

@@ -249,7 +249,7 @@ class _PropertyInducingElementTypeInference
     var analysisOptions = _libraryBuilder.kind.file.analysisOptions;
     var astResolver = AstResolver(
       _linker,
-      initializerFragment.libraryFragment as LibraryFragmentImpl,
+      initializerFragment.libraryFragment,
       scope,
       analysisOptions,
       enclosingClassElement: enclosingInterfaceElement,