Elements. Return nullable 'LibraryFragment?' from 'get libraryFragment'.

We can have synthetic 'FormalParameterFragment' and 'TypeParameterFragment'
that don't have any enclosing 'LibraryFragment'.

Change-Id: Icc1a47c308e55b93ed6a2aad70788058e26ee803
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/393500
Reviewed-by: Brian Wilkerson <[email protected]>
Commit-Queue: Konstantin Shcheglov <[email protected]>

Author: scheglov

pkg/analysis_server/lib/src/lsp/handlers/code_lens/abstract_code_lens_provider.dart

@@ -41,13 +41,13 @@ abstract class AbstractCodeLensProvider
 
     // Map the source onto a URI and only return this item if the client
     // can handle the URI.
-    var source = fragment.libraryFragment.source;
+    var source = fragment.libraryFragment!.source;
     var uri = server.uriConverter.toClientUri(source.fullName);
     if (!server.uriConverter.supportedSchemes.contains(uri.scheme)) {
       return null;
     }
 
-    var lineInfo = fragment.libraryFragment.lineInfo;
+    var lineInfo = fragment.libraryFragment!.lineInfo;
     return Location(uri: uri, range: toRange(lineInfo, nameOffset, nameLength));
   }
 

pkg/analysis_server/lib/src/lsp/mapping.dart

@@ -506,7 +506,7 @@ lsp.Location? fragmentToLocation(
     return null;
   }
 
-  var libraryFragment = fragment.libraryFragment;
+  var libraryFragment = fragment.libraryFragment!;
   var sourcePath = libraryFragment.source.fullName;
 
   var nameOffset = fragment.nameOffset2;

pkg/analysis_server/lib/src/protocol_server.dart

@@ -456,7 +456,7 @@ Location _locationForArgs(
 
 /// Creates a new [Location].
 Location _locationForArgs2(engine.Fragment fragment, engine.SourceRange range) {
-  var lineInfo = fragment.libraryFragment.lineInfo;
+  var lineInfo = fragment.libraryFragment!.lineInfo;
 
   var startLocation = lineInfo.getLocation(range.offset);
   var endLocation = lineInfo.getLocation(range.end);
@@ -467,7 +467,7 @@ Location _locationForArgs2(engine.Fragment fragment, engine.SourceRange range) {
   var endColumn = endLocation.columnNumber;
 
   return Location(
-    fragment.libraryFragment.source.fullName,
+    fragment.libraryFragment!.source.fullName,
     range.offset,
     range.length,
     startLine,

pkg/analysis_server/lib/src/services/correction/dart/create_method.dart

@@ -163,15 +163,15 @@ class CreateMethod extends ResolvedCorrectionProducer {
             target.element?.kind == ElementKind.MIXIN;
       }
       // Use different utils.
-      var targetPath = targetFragment.libraryFragment.source.fullName;
+      var targetPath = targetFragment.libraryFragment!.source.fullName;
       var targetResolveResult = await unitResult.session.getResolvedUnit(
         targetPath,
       );
       if (targetResolveResult is! ResolvedUnitResult) {
         return;
       }
     }
-    var targetSource = targetFragment?.libraryFragment.source;
+    var targetSource = targetFragment?.libraryFragment!.source;
     if (targetSource == null) {
       return;
     }

pkg/analyzer/lib/dart/element/element2.dart

@@ -646,6 +646,9 @@ abstract class ExecutableFragment implements FunctionTypedFragment {
   /// Whether the body is marked as being synchronous.
   bool get isSynchronous;
 
+  @override
+  LibraryFragment get libraryFragment;
+
   @override
   ExecutableFragment? get nextFragment;
 
@@ -929,7 +932,7 @@ abstract class Fragment {
   /// The library fragment that contains this fragment.
   ///
   /// This will be the fragment itself if it is a library fragment.
-  LibraryFragment get libraryFragment;
+  LibraryFragment? get libraryFragment;
 
   /// The name of the fragment.
   ///
@@ -1157,6 +1160,9 @@ abstract class InstanceFragment
   /// If `true`, the declaration has the explicit `augment` modifier.
   bool get isAugmentation;
 
+  @override
+  LibraryFragment get libraryFragment;
+
   /// The methods declared in this fragment.
   List<MethodFragment> get methods2;
 
@@ -2126,6 +2132,9 @@ abstract class PropertyInducingFragment
   // TODO(brianwilkerson): Should synthetic elements have a fragment?
   bool get isSynthetic;
 
+  @override
+  LibraryFragment get libraryFragment;
+
   @override
   PropertyInducingFragment? get nextFragment;
 

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

@@ -62,7 +62,7 @@ class AnalysisSessionHelper {
   /// that is not a part of a library.
   Future<ElementDeclarationResult?> getElementDeclaration2(
       Fragment fragment) async {
-    var libraryPath = fragment.libraryFragment.source.fullName;
+    var libraryPath = fragment.libraryFragment!.source.fullName;
     var resolvedLibrary = await _getResolvedLibrary(libraryPath);
     return resolvedLibrary?.getElementDeclaration2(fragment);
   }

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

@@ -8547,8 +8547,8 @@ class ParameterElementImpl extends VariableElementImpl
   ElementKind get kind => ElementKind.PARAMETER;
 
   @override
-  LibraryFragment get libraryFragment =>
-      thisOrAncestorOfType<CompilationUnitElementImpl>() as LibraryFragment;
+  LibraryFragment? get libraryFragment =>
+      thisOrAncestorOfType<CompilationUnitElementImpl>();
 
   @override
   // TODO(augmentations): Support chaining between the fragments.
@@ -9386,7 +9386,7 @@ abstract class PropertyInducingElementImpl
 
   @override
   LibraryFragment get libraryFragment =>
-      thisOrAncestorOfType<CompilationUnitElement>() as LibraryFragment;
+      thisOrAncestorOfType<CompilationUnitElementImpl>()!;
 
   @override
   PropertyInducingFragment? get nextFragment =>
@@ -10301,8 +10301,8 @@ class TypeParameterElementImpl extends ElementImpl
   ElementKind get kind => ElementKind.TYPE_PARAMETER;
 
   @override
-  LibraryFragment get libraryFragment =>
-      thisOrAncestorOfType<CompilationUnitElementImpl>() as LibraryFragment;
+  LibraryFragment? get libraryFragment =>
+      thisOrAncestorOfType<CompilationUnitElementImpl>();
 
   @override
   String get name {

pkg/analyzer/lib/src/lint/linter.dart

@@ -334,7 +334,7 @@ class LintRuleUnitContext {
 
   /// The library fragment representing the compilation unit.
   @experimental
-  LibraryFragment get libraryFragment => unit as LibraryFragment;
+  LibraryFragment get libraryFragment => unit.declaredFragment!;
 }
 
 /// An error listener that only records whether any constant related errors have

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

@@ -20,17 +20,16 @@ bool _isOldModelElement(Element2? element) {
     return false;
   }
 
-  // Skip synthetic formal parameters.
-  if (element is FormalParameterElement && element.enclosingElement2 == null) {
-    return false;
-  }
-
   var firstFragment = element.firstFragment;
   if (firstFragment == null) {
     return false;
   }
 
   var libraryFragment = firstFragment.libraryFragment;
+  if (libraryFragment == null) {
+    return false;
+  }
+
   var uriStr = libraryFragment.source.uri.toString();
 
   if (element is InstanceElement2) {