MASLayoutConstraint:0x16893030 U

iOSMASLayoutConstraint:0x16893030 UIButton:0x1684fe10.left == UIView:0x1685fb60.left + 45>

快速定位：
MASAttachKeys(self.helpBtn);

屏幕快照 2019-01-04 下午1.37.06.png

https://stackoverflow.com/questions/26389273/how-to-trap-on-uiviewalertforunsatisfiableconstraints