anchor.diff:          (elements['constant'] as Map).values.map((c) => parseConstant(c)));
   
       input['holding'].forEach((k, deps) {
  -      CodeInfo src = registry[k];
  -      assert(src != null);
  +      final src = registry[k] as CodeInfo;
         for (var dep in deps) {
  -        var target = registry[dep['id']];
  -        assert(target != null);
  +        final target = registry[dep['id']]!;
           src.uses.add(DependencyInfo(target, dep['mask']));
         }
       });
   
       input['dependencies']?.forEach((String k, dependencies) {
         List<String> deps = dependencies;
  -      result.dependencies[registry[k]] = deps.map((d) => registry[d]).toList();
  +      result.dependencies[registry[k]!] =
  +          deps.map((d) => registry[d]!).toList();
       });
   
       result.outputUnits
  
positive.code:   @override
    Map visitFunction(FunctionInfo info) {
      return _visitBasicInfo(info)
        ..addAll(<String, Object>{
          'children': _toSortedSerializedIds(info.closures, idFor),
          'modifiers': _visitFunctionModifiers(info.modifiers),
          'returnType': info.returnType,
  
negative.code:       ..inlinedCount = json['inlinedCount']
        ..modifiers = parseModifiers(Map<String, bool>.from(json['modifiers']))
        ..closures = (json['children'] as List)
            .map<ClosureInfo>((c) => parseId(c) as ClosureInfo)
            .toList();
    }
  
  