Elements. Issue 56917. Fix for thisOrAncestorOfType2() for InstanceElement2.

Bug: #56917
Change-Id: Ideda3596a7503ff98154e27353d1337b2055df02
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/390811
Commit-Queue: Konstantin Shcheglov <[email protected]>
Reviewed-by: Brian Wilkerson <[email protected]>

Author: scheglov

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

@@ -2441,8 +2441,10 @@ abstract class ElementImpl implements Element, Element2 {
   @override
   Element2? get enclosingElement2 {
     var candidate = _enclosingElement3;
-    if (candidate is CompilationUnitElementImpl ||
-        candidate is AugmentableElement) {
+    if (candidate is CompilationUnitElementImpl) {
+      throw UnsupportedError('Cannot get an enclosingElement2 for a fragment');
+    }
+    if (candidate is AugmentableElement) {
       throw UnsupportedError('Cannot get an enclosingElement2 for a fragment');
     }
     return candidate as Element2?;
@@ -7138,12 +7140,20 @@ mixin MaybeAugmentedInstanceElementMixin
   @override
   E? thisOrAncestorMatching2<E extends Element2>(
     bool Function(Element2) predicate,
-  ) =>
-      declaration.thisOrAncestorMatching2(predicate);
+  ) {
+    if (predicate(this)) {
+      return this as E;
+    }
+    return library2.thisOrAncestorMatching2(predicate);
+  }
 
   @override
-  E? thisOrAncestorOfType2<E extends Element2>() =>
-      declaration.thisOrAncestorOfType2<E>();
+  E? thisOrAncestorOfType2<E extends Element2>() {
+    if (this case E result) {
+      return result;
+    }
+    return library2.thisOrAncestorOfType2<E>();
+  }
 
   @override
   void visitChildren2<T>(ElementVisitor2<T> visitor) {

pkg/analyzer/test/src/summary/element_text.dart

@@ -950,6 +950,11 @@ class _Element2Writer extends _AbstractElementWriter {
   }
 
   void _writeInstanceElement(InstanceElement2 e) {
+    expect(e.thisOrAncestorOfType2<InstanceElement2>(), same(e));
+    expect(e.thisOrAncestorOfType2<GetterElement>(), isNull);
+    expect(e.thisOrAncestorMatching2((_) => true), same(e));
+    expect(e.thisOrAncestorMatching2((_) => false), isNull);
+
     _sink.writeIndentedLine(() {
       switch (e) {
         case ClassElement2():