Cannot initialize a parameter of type 'id<NSCopying> _Nonnull' with an rvalue of type 'Class'

[FycGitHub]

NSArray> *FBGetObjectStrongReferences(id obj, NSMutableDictionary> *> *layoutCache) { NSMutableArray> *array = [NSMutableArray new];

__unsafe_unretained Class previousClass = nil;
__unsafe_unretained Class currentClass = object_getClass(obj);

while (previousClass != currentClass) {
NSArray<id> *ivars;

if (layoutCache && currentClass) {
  ivars = layoutCache[currentClass];
}

if (!ivars) {
  ivars = FBGetStrongReferencesForClass(currentClass);
  if (layoutCache && currentClass) {
    layoutCache[currentClass] = ivars;
  }
}
[array addObjectsFromArray:ivars];

previousClass = currentClass;
currentClass = class_getSuperclass(currentClass);

}

return [array copy];
}

问题总结：
layoutCache[currentClass] = ivars; 这行代码报的错，注释掉就能正常编译

[lexuanquynh]

how to fix it? if you comment this line code. Did it generate an error?

[CaiChenghan]

可以这么改：

layoutCache[(id<NSCopying>)currentClass] = ivars;

facebook/FBRetainCycleDetector#115