UITextField+BlocksKit crashes this.

EditUserWordController

void -[EditUserWordController viewDidAppear:](void * self, void * _cmd, bool arg2) {
    rbx = self;
    var_28 = rbx;
    var_20 = *0x2bd50;
    LODWORD(rdx) = LOBYTE(arg2) & 0xff;
    [[var_28 super] viewDidAppear:rdx];
    if ([[rbx targetTextField] delegate] != rbx) {
            r15 = *objc_msgSend;
            rdx = [[rbx targetTextField] delegate];
            [rbx setOriginalTargetDelegate:rdx];
            rdx = [[rbx shortcutTextField] delegate];
            [rbx setOriginalShortcutDelegate:rdx];
            rax = [rbx targetTextField];
            [rax setDelegate:rbx];
            rax = [rbx shortcutTextField];
            rdx = rbx;
            [rax setDelegate:rdx];
    }
    r15 = *objc_msgSend;
    r14 = [rbx targetTextField];
    if ([[r14 text] length] != 0x0) {
            rax = [rbx _shouldSetDefaultFirstResponder];
            if ((LOBYTE(rax) != 0x0) || ([[[rbx shortcutTextField] text] length] == 0x0)) {
                    r15 = *objc_msgSend;
                    rax = [rbx shortcutTextField];
                    [rax becomeFirstResponder];
            }
    }
    else {
            [r14 becomeFirstResponder];
    }
    r15 = *objc_msgSend;
    r14 = [[rbx navigationItem] rightBarButtonItem];
    rax = [rbx shortcutTextField];
    rax = [rax text];
    rax = [rax length];
    rax = [r14 setEnabled:LOBYTE(rax != 0x0 ? 0x1 : 0x0) & 0xff];
    return;
}

TextFieldViewController.h

//
//  TextFieldViewController.h
//  BKDemo
//
//  Created by Tony Li on 1/25/15.
//  Copyright (c) 2015 Tony Li. All rights reserved.
//

#import <UIKit/UIKit.h>

@interface TextFieldViewController : UIViewController<UITextFieldDelegate>

@property (nonatomic, readonly) UITextField *textField;

@end

TextFieldViewController.m

//
//  TextFieldViewController.m
//  BKDemo
//
//  Created by Tony Li on 1/25/15.
//  Copyright (c) 2015 Tony Li. All rights reserved.
//

#import "TextFieldViewController.h"

@interface SomeTextFieldDelegate : NSObject<UITextFieldDelegate>

@end

@implementation SomeTextFieldDelegate

- (BOOL)textFieldShouldBeginEditing:(UITextField *)textField
{
  return YES;
}

@end

static SomeTextFieldDelegate *textFieldDelegate;

@implementation TextFieldViewController {
  id<UITextFieldDelegate> _originalDelegate;
}

- (void)viewDidLoad
{
  [super viewDidLoad];

  self.view.backgroundColor = [UIColor whiteColor];

  _textField = [[UITextField alloc] init];
  _textField.borderStyle = UITextBorderStyleRoundedRect;
  textFieldDelegate = [SomeTextFieldDelegate new];
  _textField.delegate = textFieldDelegate;
  _textField.bounds = CGRectMake(0, 0, self.view.bounds.size.width - 20, 44);
  _textField.center = CGPointMake(CGRectGetMidX(self.view.bounds), CGRectGetMidY(self.view.bounds));
  [self.view addSubview:_textField];

  // `_originalDelegate` should be `textFieldDelegate` which is setted in line 39.
  // But actually it is an instance of `A2DynamicUITextFieldDelegate`.
  _originalDelegate = _textField.delegate;
  _textField.delegate = self;

  [_textField becomeFirstResponder];
}

- (BOOL)textFieldShouldBeginEditing:(UITextField *)textField
{
  return [_originalDelegate textFieldShouldBeginEditing:textField];
}

@end