Print out instance in Xcode console issue

Question

I use po command in Xcode console to check some needed information. So after I used po vc I have this:

(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 it's my UIViewController. I've checked it in this block of code after init:

+ (MyVC *)_new; {

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