anchor.diff:  @reflectiveTest
   class ResynthesizeAst2Test extends ResynthesizeTestStrategyTwoPhase
       with ResynthesizeTestCases {
  +  /// The shared SDK bundle, computed once and shared among test invocations.
  +  static LinkedNodeBundle _sdkBundle;
  +
     @override
     bool get isAstBasedSummary => true;
  +
  +  LinkedNodeBundle get sdkBundle {
  +    if (_sdkBundle != null) return _sdkBundle;
  +
  +    var sdkUnitMap = <Source, Map<Source, CompilationUnit>>{};
  +    for (var sdkLibrary in sdk.sdkLibraries) {
  +      var source = sourceFactory.resolveUri(null, sdkLibrary.shortName);
  +      var text = getFile(source.fullName).readAsStringSync();
  +      var unit = parseText(text);
  +      sdkUnitMap[source] = _unitsOfLibrary(source, unit);
  +    }
  +
  +    var sdkLinkResult = link(
  +      AnalysisOptionsImpl(),
  +      sourceFactory,
  +      declaredVariables,
  +      [],
  +      sdkUnitMap,
  +    );
  +
  +    var bytes = sdkLinkResult.bundle.toBuffer();
  +    return _sdkBundle = LinkedNodeBundle.fromBuffer(bytes);
  +  }
   
     @override
     Future<LibraryElementImpl> checkLibrary(String text,
         {bool allowErrors = false, bool dumpSummaries = false}) async {
  -    var dartCoreSource = sourceFactory.forUri('dart:core');
  -    var dartAsyncSource = sourceFactory.forUri('dart:async');
  -    var dartMathSource = sourceFactory.forUri('dart:math');
  -
  -    var dartCoreCode = getFile(dartCoreSource.fullName).readAsStringSync();
  -    dartCoreCode = r'''
  -library dart.core;
  -
  -abstract class Comparable<T> {
  -  int compareTo(T other);
  -}
  -
  -class Iterable<E> {
  -  Iterable<R> map<R>(R f(E e));
  -
  -  List<E> toList();
  -}
  -
  -class Iterator<T> {}
  -
  -class List<E> implements Iterable<E> {}
  -
  -class Map<K, V> {}
  -
  -abstract class Null {}
  -
  -class Object {
  -  const Object();
  -  
  -  String toString();
  -}
  -
  -abstract class String {
  -  int get length;
  -  String operator +(String other);
  -}
  -
  -class Set<T> {}
  -
  -abstract class Symbol {}
  -
  -abstract class Type {}
  -
  -abstract class bool {}
  -
  -abstract class double extends num {}
  -
  -abstract class int extends num {
  -  bool get isEven => false;
  -  bool get isNegative;
  -  
  -  int operator &(int other);
  -  int operator -();
  -  int operator <<(int shiftAmount);
  -  int operator >>(int shiftAmount);
  -  int operator ^(int other);
  -  int operator |(int other);
  -  int operator ~();
  -}
  -
  -abstract class num implements Comparable<num> {
  -  bool operator <(num other);
  -  bool operator <=(num other);
  -  bool operator ==(Object other);
  -  bool operator >(num other);
  -  bool operator >=(num other);
  -  
  -  double operator /(num other);
  -  double toDouble();
  -  
  -  int operator <<(int other);
  -  int operator >>(int other);
  -  int operator ^(int other);
  -  int operator |(int other);
  -  int operator ~();
  -  int operator ~/(num other);
  -  
  -  int round();
  -  int toInt();
  -  num abs();
  -  
  -  num operator %(num other);
  -  num operator *(num other);
  -  num operator +(num other);
  -  num operator -();
  -  num operator -(num other);
  -}
  -''';
  -
  -    var dartAsyncCode = r'''
  -library dart.async;
  -
  -class Future<T> {}
  -
  -class FutureOr<T> {}
  -
  -class Stream<T> {}
  -''';
  -
  -    var dartMathCode = r'''
  -library dart.math;
  -
  -const double E = 2.718281828459045;
  -const double PI = 3.1415926535897932;
  -const double LN10 =  2.302585092994046;
  -
  -T min<T extends num>(T a, T b) => null;
  -T max<T extends num>(T a, T b) => null;
  -''';
  -
  -    var dartCoreResult = _link({
  -      dartCoreSource: dartCoreCode,
  -      dartAsyncSource: dartAsyncCode,
  -      dartMathSource: dartMathCode,
  -    });
  -
       var source = addTestSource(text);
       var unit = parseText(text, experimentStatus: experimentStatus);
   
  
positive.code:       AnalysisOptionsImpl(),
        sourceFactory,
        declaredVariables,
        [dartCoreResult.bundle],
        libraryUnitMap,
      );
  
  
negative.code:   @failingTest
    test_unresolved_import() async {
      await super.test_unresolved_import();
    }
  
    Map<Source, CompilationUnit> _unitsOfLibrary(
  