Implement SyntheticVariableElementForLink.isSynthetic.

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

Index: pkg/analyzer/test/src/summary/linker_test.dart
diff --git a/pkg/analyzer/test/src/summary/linker_test.dart b/pkg/analyzer/test/src/summary/linker_test.dart
index ea48786fd7928b8831a27ba18104eef0c74899cc..2920e50d6572409961ba12aed828be1e7df9e0ee 100644
--- a/pkg/analyzer/test/src/summary/linker_test.dart
+++ b/pkg/analyzer/test/src/summary/linker_test.dart
@@ -38,6 +38,20 @@ class LinkerUnitTest extends SummaryLinkerTest {
     return linker.getLibrary(Uri.parse(uri));
   }
 
+  void test_baseClass_genericWithAccessor() {
+    createLinker('''
+class B<T> {
+  int get i => null;
+}
+class C<U> extends B<U> {
+  var j;
+}
+    ''');
+    LibraryElementForLink library = linker.getLibrary(linkerInputs.testDartUri);
+    library.libraryCycleForLink.ensureLinked();
+    // No assertions--just make sure it doesn't crash.
+  }
+
   void test_baseClass_withPrivateField() {
     createLinker('''
 class B {