frontend\models\SignupMobileVerifyForm::rules PHP Method

    public function rules()
    {
        return [[['verifyCode'], 'string', 'length' => 6], [['verifyCode'], function ($attribute, $params) {
            if ($this->_session['mobileSignupVerifyCode'] !== $this->verifyCode) {
                $this->addError($attribute, '验证码不匹配！');
            }
        }]];
    }