在Xcode控制台问题

Question

我在Xcode控制台中使用po命令来检查一些所需的信息。所以在我使用po vc后，我有了这个：

(lldb) po vc
error: field '__FuncPtr' declared with incompatible types in different translation units ('void (*)(id)' vs. 'void (*)()')
error: instance variable '_afterAppearance' declared with incompatible types in different translation units ('__block_literal_generic *' vs. '__block_literal_generic *')
note: declared here with type 'void (*)()'
note: declared here with type '__block_literal_generic *'
error: 2 errors parsing expression

po vc它是我的UIViewController。我在init之后在这段代码中检查了它：

+ (MyVC *)_new; {

    MyVC *vc = [[MyVC alloc] initWithNibName:nil bundle:nil];
    return vc;
}