[analyzer] Add declaredFragment getters to a few more AST nodes.

This change adds the getters
`DeclaredVariablePattern.declaredFragment`,
`GenericFunctionType.declaredFragment`, and `Label.declaredFragment`,
for consistency with other AST nodes that have associated fragments.

Change-Id: Ica7b6d2fbfafeaff61e75f1eb89c26be36aede54
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/412382
Reviewed-by: Brian Wilkerson <[email protected]>
Reviewed-by: Konstantin Shcheglov <[email protected]>
Commit-Queue: Paul Berry <[email protected]>

Author: stereotype441

pkg/analyzer/api.txt

@@ -708,6 +708,7 @@ package:analyzer/dart/ast/ast.dart:
   DeclaredVariablePattern (class extends Object implements VariablePattern):
     declaredElement (getter: BindPatternVariableElement?)
     declaredElement2 (getter: BindPatternVariableElement2?)
+    declaredFragment (getter: BindPatternVariableFragment?)
     keyword (getter: Token?)
     type (getter: TypeAnnotation?)
   DefaultFormalParameter (class extends Object implements FormalParameter):
@@ -949,6 +950,7 @@ package:analyzer/dart/ast/ast.dart:
     returnType (getter: TypeAnnotation?)
     typeParameters (getter: TypeParameterList?)
   GenericFunctionType (class extends Object implements TypeAnnotation):
+    declaredFragment (getter: GenericFunctionTypeFragment?)
     functionKeyword (getter: Token)
     parameters (getter: FormalParameterList)
     returnType (getter: TypeAnnotation?)
@@ -1049,6 +1051,7 @@ package:analyzer/dart/ast/ast.dart:
     type (getter: TypeAnnotation)
   Label (class extends Object implements AstNode):
     colon (getter: Token)
+    declaredFragment (getter: LabelFragment?)
     label (getter: SimpleIdentifier)
   LabeledStatement (class extends Object implements Statement):
     labels (getter: NodeList<Label>)

pkg/analyzer/lib/src/dart/ast/ast.dart

@@ -5025,6 +5025,11 @@ sealed class DeclaredVariablePattern implements VariablePattern {
   @experimental
   BindPatternVariableElement2? get declaredElement2;
 
+  /// The fragment declared by this declaration.
+  ///
+  /// Returns `null` if the AST structure hasn't been resolved.
+  BindPatternVariableFragment? get declaredFragment;
+
   /// The `var` or `final` keyword.
   Token? get keyword;
 
@@ -5061,6 +5066,9 @@ final class DeclaredVariablePatternImpl extends VariablePatternImpl
     return declaredElement?.element;
   }
 
+  @override
+  BindPatternVariableElementImpl? get declaredFragment => declaredElement;
+
   @override
   Token get endToken => name;
 
@@ -9093,6 +9101,11 @@ final class FunctionTypedFormalParameterImpl extends NormalFormalParameterImpl
 ///        [ normalParameterTypes ,? ]
 @AnalyzerPublicApi(message: 'exported by lib/dart/ast/ast.dart')
 abstract final class GenericFunctionType implements TypeAnnotation {
+  /// The fragment declared by this declaration.
+  ///
+  /// Returns `null` if the AST structure hasn't been resolved.
+  GenericFunctionTypeFragment? get declaredFragment;
+
   /// The `Function` keyword.
   Token get functionKeyword;
 
@@ -9148,6 +9161,7 @@ final class GenericFunctionTypeImpl extends TypeAnnotationImpl
   @override
   Token get beginToken => _returnType?.beginToken ?? functionKeyword;
 
+  @override
   GenericFunctionTypeElementImpl? get declaredFragment {
     return declaredElement;
   }
@@ -10988,6 +11002,11 @@ abstract final class Label implements AstNode {
   /// The colon that separates the label from the statement.
   Token get colon;
 
+  /// The fragment declared by this declaration.
+  ///
+  /// Returns `null` if the AST structure hasn't been resolved.
+  LabelFragment? get declaredFragment;
+
   /// The label being associated with the statement.
   SimpleIdentifier get label;
 }
@@ -11076,6 +11095,10 @@ final class LabelImpl extends AstNodeImpl implements Label {
   @override
   Token get beginToken => _label.beginToken;
 
+  @override
+  LabelElementImpl? get declaredFragment =>
+      (label.element as LabelElementImpl2?)?.firstFragment;
+
   @override
   Token get endToken => colon;