anchor.diff:    }
   
     void test_computeValues_dependentVariables() {
  -    Source librarySource = addSource(r'''
  +    Source source = addSource(r'''
   const int b = a;
   const int a = 0;''');
  -    LibraryElement libraryElement = resolve2(librarySource);
  +    LibraryElement libraryElement = resolve2(source);
       CompilationUnit unit =
  -        analysisContext.resolveCompilationUnit(librarySource, libraryElement);
  +        analysisContext.resolveCompilationUnit(source, libraryElement);
       expect(unit, isNotNull);
       ConstantValueComputer computer = _makeConstantValueComputer();
  -    computer.add(unit, librarySource, librarySource);
  +    computer.add(unit, source, source);
       computer.computeValues();
       NodeList<CompilationUnitMember> members = unit.declarations;
       expect(members, hasLength(2));
  
positive.code:     TestLogger logger = new TestLogger();
      AnalysisEngine.instance.logger = logger;
      try {
        Source librarySource = addSource(r'''
    const int a = c;
    const int b = a;
    const int c = b;''');
        LibraryElement libraryElement = resolve2(librarySource);
        CompilationUnit unit =
            analysisContext.resolveCompilationUnit(librarySource, libraryElement);
        analysisContext.computeErrors(librarySource);
        expect(unit, isNotNull);
        ConstantValueComputer computer = _makeConstantValueComputer();
        computer.add(unit, librarySource, librarySource);
        computer.computeValues();
        NodeList<CompilationUnitMember> members = unit.declarations;
        expect(members, hasLength(3));
  
negative.code:   }
  
    void test_computeValues_value_depends_on_enum() {
      Source source = addSource('''
  enum E { id0, id1 }
  const E e = E.id0;
  ''');
      LibraryElement libraryElement = resolve2(source);
      CompilationUnit unit =
          analysisContext.resolveCompilationUnit(source, libraryElement);
      expect(unit, isNotNull);
      ConstantValueComputer computer = _makeConstantValueComputer();
      computer.add(unit, source, source);
      computer.computeValues();
      TopLevelVariableDeclaration declaration = unit.declarations
          .firstWhere((member) => member is TopLevelVariableDeclaration);
  