anchor.diff:        var definedNames = computeDefinedNames(unit);
         var referencedNames = computeReferencedNames(unit);
         var subtypedNames = computeSubtypedNames(unit);
  -      var bytes = AnalysisDriverUnlinkedUnit(
  +      var driverUnlinkedUnit = AnalysisDriverUnlinkedUnit(
           definedTopLevelNames: definedNames.topLevelNames,
           definedClassMemberNames: definedNames.classMemberNames,
           referencedNames: referencedNames,
           subtypedNames: subtypedNames,
           unit: unlinkedUnit,
  -      ).toBytes();
  +      );
  +      var bytes = driverUnlinkedUnit.toBytes();
         _fsState._byteStore.put(_unlinkedKey!, bytes);
         counterUnlinkedBytes += bytes.length;
         counterUnlinkedLinkedBytes += bytes.length;
  -      return bytes;
  +      return driverUnlinkedUnit;
       });
     }
   
  
positive.code:     return _fsState.getFileForUri(absoluteUri);
    }
  
    /// Return the bytes of the unlinked summary - existing or new.
    Uint8List _getUnlinkedBytes() {
      var bytes = _fsState._byteStore.get(_unlinkedKey!);
      if (bytes != null && bytes.isNotEmpty) {
        return bytes;
      }
  
      var unit = parse();
  
negative.code:       _informativeKey = '$signatureHex.ast';
      }
  
      // Prepare the unlinked unit.
      _driverUnlinkedUnit = _getUnlinkedUnit();
      _unlinked2 = _driverUnlinkedUnit!.unit;
      _lineInfo = LineInfo(_unlinked2!.lineStarts);
  
  