anchor.diff:  
       group('Expression compiler tests in extension method:', () {
         var source = '''
  -        ${setup.dartLangComment}
           extension NumberParsing on String {
             int parseInt() {
               var ret = int.parse(this);
  
positive.code:         returnByValue: false);
  
      await debugger.removeBreakpoint(bp.breakpointId);
  
      var value = evalResult.type == 'function'
          ? evalResult.description
          : evalResult.value;
  
      expect(
          result,
          const TypeMatcher<TestCompilationResult>()
              .having((_) => '$value', 'result', _matches(expectedResult)));
    }
  
    /// Collects local JS variables visible at a breakpoint during evaluation.
  
negative.code: 
      group('Expression compiler scope collection tests', () {
        var source = '''
          class C {
            static int staticField = 0;
            int field;
  
            C(this.field);
  
            void methodFieldAccess(int x) {
  