1. You can’t find the error by using the breakpoint tool. Finally, you read the error information carefully

2. Error information

[LayoutConstraints] Unable to simultaneously satisfy constraints.
	Probably at least one of the constraints in the following list is one you don't want. 
	Try this: 
		(1) look at each constraint and try to figure out which you don't expect; 
		(2) find the code that added the unwanted constraint or constraints and fix it. 
(
    "<NSLayoutConstraint:0x608000098a60 UIView:0x7fcb7b428fe0.height == 50   (active)>",
    "<NSLayoutConstraint:0x608000098060 V:|-(0)-[UIView:0x7fcb7b428fe0]   (active, names: '|':UITableViewCellContentView:0x7fcb7b42bd40 )>",
    "<NSLayoutConstraint:0x608000097b60 V:[UIView:0x7fcb7b42ed00]-(0)-|   (active, names: '|':UITableViewCellContentView:0x7fcb7b42bd40 )>",
    "<NSLayoutConstraint:0x608000097c00 V:[UIView:0x7fcb7b428fe0]-(0)-[UIView:0x7fcb7b42ed00]   (active)>",
    "<NSLayoutConstraint:0x60000009bf80 'UIView-Encapsulated-Layout-Height' UITableViewCellContentView:0x7fcb7b42bd40.height == 49.5   (active)>"
)

Will attempt to recover by breaking constraint 
<NSLayoutConstraint:0x608000098a60 UIView:0x7fcb7b428fe0.height == 50   (active)>

Make a symbolic breakpoint at UIViewAlertForUnsatisfiableConstraints to catch this in the debugger.
The methods in the UIConstraintBasedLayoutDebugging category on UIView listed in <UIKit/UIView.h> may also be helpful.

3.Analytis

 "<NSLayoutConstraint:0x608000098a60 UIView:0x7fcb7b428fe0.height == 50   (active)>",
"<NSLayoutConstraint:0x60000009bf80 'UIView-Encapsulated-Layout-Height' UITableViewCellContentView:0x7fcb7b42bd40.height == 49.5   (active)>"

The first sentence of code information is that there is an interface in the view with a height of 50
the second sentence means cell_The height of contentview is 49.5

Here comes the problem

The contentview is not as large as the self view I set, and I set clips to view = yes for the cell
if the constraint conflicts, Xcode will give an error message

Increase the height of the cell or decrease the height of the vie