Deprecate Element.getAncestor, replacing it with methods matching tho…

…se in AstNode

Change-Id: Iebb046791c1fce57a228f997e9c5936809fbc872
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/127481
Reviewed-by: Konstantin Shcheglov <scheglov@google.com>
Commit-Queue: Brian Wilkerson <brianwilkerson@google.com>

pkg/analysis_server/lib/src/computer/computer_hover.dart

@@ -73,8 +73,7 @@ class DartUnitHoverComputer {
         // not local element
         if (element.enclosingElement is! ExecutableElement) {
           // containing class
-          ClassElement containingClass =
-              element.getAncestor((e) => e is ClassElement);
+          ClassElement containingClass = element.thisOrAncestorOfType();
           if (containingClass != null) {
             hover.containingClassDescription = containingClass.displayName;
           }

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

@@ -179,7 +179,7 @@ CompilationUnitElement getCompilationUnitElement(Element element) {
   if (element is CompilationUnitElement) {
     return element;
   }
-  return element.getAncestor((e) => e is CompilationUnitElement);
+  return element.thisOrAncestorOfType();
 }
 
 String getDefaultValueCode(DartType type) {

pkg/analysis_server/lib/src/services/refactoring/rename_class_member.dart

@@ -262,7 +262,7 @@ class _ClassMemberValidator {
     var visibleRangeMap = <LocalElement, SourceRange>{};
 
     Future<List<LocalElement>> getLocalElements(Element element) async {
-      var unitElement = element.getAncestor((e) => e is CompilationUnitElement);
+      var unitElement = element.thisOrAncestorOfType<CompilationUnitElement>();
       var localElements = localElementMap[unitElement];
 
       if (localElements == null) {

pkg/analysis_server/lib/src/services/refactoring/rename_extension_member.dart

@@ -157,7 +157,7 @@ class _ExtensionMemberValidator {
     var visibleRangeMap = <LocalElement, SourceRange>{};
 
     Future<List<LocalElement>> getLocalElements(Element element) async {
-      var unitElement = element.getAncestor((e) => e is CompilationUnitElement);
+      var unitElement = element.thisOrAncestorOfType<CompilationUnitElement>();
       var localElements = localElementMap[unitElement];
 
       if (localElements == null) {

pkg/analysis_server/lib/src/services/refactoring/rename_unit_member.dart

@@ -253,7 +253,7 @@ class _RenameUnitMemberValidator {
   void _validateWillBeShadowed() {
     for (SearchMatch reference in references) {
       Element refElement = reference.element;
-      ClassElement refClass = refElement.getAncestor((e) => e is ClassElement);
+      ClassElement refClass = refElement.thisOrAncestorOfType();
       if (refClass != null) {
         visitChildren(refClass, (shadow) {
           if (hasDisplayName(shadow, name)) {
@@ -304,8 +304,7 @@ class _RenameUnitMemberValidator {
           continue;
         }
         // cannot be shadowed if declared in the same class as reference
-        ClassElement refClass =
-            refElement.getAncestor((e) => e is ClassElement);
+        ClassElement refClass = refElement.thisOrAncestorOfType();
         if (refClass == declaringClass) {
           continue;
         }

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

@@ -389,7 +389,7 @@ abstract class AstNode implements SyntacticEntity {
 
   /// Return either this node or the most immediate ancestor of this node that
   /// has the given type, or `null` if there is no such node.
-  T thisOrAncestorOfType<T extends AstNode>();
+  E thisOrAncestorOfType<E extends AstNode>();
 
   /// Return a textual description of this node in a form approximating valid
   /// source.

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

@@ -646,6 +646,7 @@ abstract class Element implements AnalysisTarget {
   /// Return the most immediate ancestor of this element for which the
   /// [predicate] returns `true`, or `null` if there is no such ancestor. Note
   /// that this element will never be returned.
+  @Deprecated('Use either thisOrAncestorMatching or thisOrAncestorOfType')
   E getAncestor<E extends Element>(Predicate<Element> predicate);
 
   /// Return a display name for the given element that includes the path to the
@@ -664,6 +665,15 @@ abstract class Element implements AnalysisTarget {
   /// </blockquote>
   bool isAccessibleIn(LibraryElement library);
 
+  /// Return either this element or the most immediate ancestor of this element
+  /// for which the [predicate] returns `true`, or `null` if there is no such
+  /// element.
+  E thisOrAncestorMatching<E extends Element>(Predicate<Element> predicate);
+
+  /// Return either this element or the most immediate ancestor of this element
+  /// that has the given type, or `null` if there is no such element.
+  E thisOrAncestorOfType<E extends Element>();
+
   /// Use the given [visitor] to visit all of the children of this element.
   /// There is no guarantee of the order in which the children will be visited.
   void visitChildren(ElementVisitor visitor);

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

@@ -814,7 +814,6 @@ abstract class AstNodeImpl implements AstNode {
 
   @override
   E thisOrAncestorMatching<E extends AstNode>(Predicate<AstNode> predicate) {
-    // TODO(brianwilkerson) It is a bug that this method can return `this`.
     AstNode node = this;
     while (node != null && !predicate(node)) {
       node = node.parent;
@@ -823,12 +822,12 @@ abstract class AstNodeImpl implements AstNode {
   }
 
   @override
-  T thisOrAncestorOfType<T extends AstNode>() {
+  E thisOrAncestorOfType<E extends AstNode>() {
     AstNode node = this;
-    while (node != null && node is! T) {
+    while (node != null && node is! E) {
       node = node.parent;
     }
-    return node as T;
+    return node as E;
   }
 
   @override

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

@@ -2916,8 +2916,7 @@ abstract class ElementImpl implements Element {
   }
 
   @override
-  LibraryElement get library =>
-      getAncestor((element) => element is LibraryElement);
+  LibraryElement get library => thisOrAncestorOfType();
 
   @override
   Source get librarySource => library?.source;
@@ -3029,6 +3028,7 @@ abstract class ElementImpl implements Element {
     }
   }
 
+  @Deprecated('Use either thisOrAncestorMatching or thisOrAncestorOfType')
   @override
   E getAncestor<E extends Element>(Predicate<Element> predicate) {
     var ancestor = _enclosingElement;
@@ -3087,6 +3087,24 @@ abstract class ElementImpl implements Element {
     _modifiers = BooleanArray.set(_modifiers, modifier.ordinal, value);
   }
 
+  @override
+  E thisOrAncestorMatching<E extends Element>(Predicate<Element> predicate) {
+    Element element = this;
+    while (element != null && !predicate(element)) {
+      element = element.enclosingElement;
+    }
+    return element as E;
+  }
+
+  @override
+  E thisOrAncestorOfType<E extends Element>() {
+    Element element = this;
+    while (element != null && element is! E) {
+      element = element.enclosingElement;
+    }
+    return element as E;
+  }
+
   @override
   String toString() {
     StringBuffer buffer = StringBuffer();
@@ -6234,6 +6252,7 @@ class MultiplyDefinedElementImpl implements MultiplyDefinedElement {
   T accept<T>(ElementVisitor<T> visitor) =>
       visitor.visitMultiplyDefinedElement(this);
 
+  @Deprecated('Use either thisOrAncestorMatching or thisOrAncestorOfType')
   @override
   E getAncestor<E extends Element>(Predicate<Element> predicate) => null;
 
@@ -6255,6 +6274,13 @@ class MultiplyDefinedElementImpl implements MultiplyDefinedElement {
     return false;
   }
 
+  @override
+  E thisOrAncestorMatching<E extends Element>(Predicate<Element> predicate) =>
+      null;
+
+  @override
+  E thisOrAncestorOfType<E extends Element>() => null;
+
   @override
   String toString() {
     StringBuffer buffer = StringBuffer();

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

@@ -551,6 +551,7 @@ abstract class Member implements Element {
    */
   MapSubstitution get substitution => _substitution;
 
+  @Deprecated('Use either thisOrAncestorMatching or thisOrAncestorOfType')
   @override
   E getAncestor<E extends Element>(Predicate<Element> predicate) =>
       declaration.getAncestor(predicate);
@@ -575,6 +576,14 @@ abstract class Member implements Element {
     }
   }
 
+  @override
+  E thisOrAncestorMatching<E extends Element>(Predicate<Element> predicate) =>
+      declaration.thisOrAncestorMatching(predicate);
+
+  @override
+  E thisOrAncestorOfType<E extends Element>() =>
+      declaration.thisOrAncestorOfType<E>();
+
   @override
   void visitChildren(ElementVisitor visitor) {
     // There are no children to visit
@@ -840,6 +849,7 @@ class ParameterMember extends VariableMember
   @override
   T accept<T>(ElementVisitor<T> visitor) => visitor.visitParameterElement(this);
 
+  @Deprecated('Use either thisOrAncestorMatching or thisOrAncestorOfType')
   @override
   E getAncestor<E extends Element>(Predicate<Element> predicate) {
     Element element = declaration.getAncestor(predicate);

pkg/analyzer/lib/src/diagnostic/diagnostic_factory.dart

@@ -57,8 +57,7 @@ class DiagnosticFactory {
     List<DiagnosticMessage> contextMessages;
     int declarationOffset = staticElement.nameOffset;
     if (declarationOffset >= 0 && staticElement != null) {
-      CompilationUnitElement unit = staticElement
-          .getAncestor((element) => element is CompilationUnitElement);
+      CompilationUnitElement unit = staticElement.thisOrAncestorOfType();
       CharacterLocation location = unit.lineInfo.getLocation(declarationOffset);
       contextMessages = [
         DiagnosticMessageImpl(

pkg/analyzer/lib/src/generated/element_resolver.dart

@@ -1225,8 +1225,8 @@ class ElementResolver extends SimpleAstVisitor<void> {
       }
       // The target has been found.
       labelNode.staticElement = definingScope.element;
-      ExecutableElement labelContainer = definingScope.element
-          .getAncestor((element) => element is ExecutableElement);
+      ExecutableElement labelContainer =
+          definingScope.element.thisOrAncestorOfType();
       if (!identical(labelContainer, _resolver.enclosingFunction)) {
         _resolver.errorReporter.reportErrorForNode(
             CompileTimeErrorCode.LABEL_IN_OUTER_SCOPE,