In general, you should not touch the layout of Apple's view classes other than using them as a reference for positioning your own views.

Exactly.

But when people use these libraries that “helpfully” set `translatesAutoresizingMaskIntoConstraints = false` for them and they don’t understand what’s going on under the hood, their layout breaks and they start complaining about autolayout being “buggy”.

What's the solution in such a scenario? If I'm making custom cells, I'm going to constrain my views to the contentView. If I use a library like SnapKit, then the library sets translatesAutoresizingMaskIntoConstraints to false. Should I override that somehow and set it back to true? Should I use normal NSLayoutConstraints for all constraints involving contentView? That doesn't seem ideal.

You can use the regular NSLayoutConstraints.activate() API, or you can set it back to true.

Also, notice that translatesAutoresizingMaskIntoConstraints will only be set on the view which you call `layout` on. I.e. this is bogus:

    self.contentView.layout { make in
          make.left.equal(self.otherView)
    }

But this is “fine”:

    self.otherView.layout { make in
        make.left.equal(self.contentView)
    }

Of course now you’re relying on implementation details of SnapKot/Masonry/whatever.

I personally just use the built-in anchor APIs with a few helpers (e.g. to create constraints to match all 4 edges of two views). In swift you have operator+ for arrays, so NSLayoutConstraints.activate(...) can be pretty succint this way.