Xcode 9 - "Fixed Width Constraints May Cause Clipping" and Other Localization Warnings

I was getting the same warnings even without multiple languages in my app, which led me to find out what was really going on. . .

There are a few different things going on here. I was able to silence the fixed-width warnings in my own app by changing the width of the object spacings from fixed width to greater than or equal or less than or equal.

This can be done by selecting the object in interface builder, going to the size inspector and changing it there:

Or, select the constraint from the document outline, go to size inspector, and change it there:

As far as the warning at the top of your screenshot:

Fixed leading and trailing constraints with a center constraint may cause clipping

Here is a screenshot from my own app in which I was getting the exact same warning:

I had the label with the @ sign set to leading and trailing to the buttons but also to align the center with the rating label. Once I removed the center alignment constraint, the warning disappeared, but I was left with an improperly laid out set of objects.

It is then that I resigned myself to embrace the Stack View. As annoying as it is to use, when you get all of the constraints and settings right, it lays out beautifully and with no warnings.

Edit

As Repose writes in the comments, sometimes simply adding >= 0 will be what you need, as you are making sure two elements do not overlap.

You can try Disabling "Respect Language Direction" on per Constraint basis to silence the warning and see if it helps. Select your constraint and open Attributes/Size Inspector. Please see image attached.

If you are not planning on localizing your app to other languages, then this solution should not have any fallbacks. For localized apps you have to be more conscious of your label and font sizes.

p.s. This solution works for iOS. For macOS try >= or <= to silence the warning.

p.p.s. Labels in the picture below are much easier to create using AutoLayout and attributedString property on a single UILabel or UITextView using NSMutableAttributedString. The image is for demonstration purposes only.

For labels and buttons which are localized this warning makes sense and you should provide the necessary constraints so your labels don't overlap. If they don't overlap now they might in the future, so it won't hurt to provide the constraints.

Xcode helps you add these constraints automatically:

In the document outline of your storyboard click on the yellow arrow and either choose "fixed leading" or "fixed trailing", depending on where the text is on your screen (left or right). This will fix it for most issues.

If you have this issue with a Button without any text (only image), try to remove the "default title" which might still be set for the button: