我在我的根 UIView 上设置了 translatesAutoresizingMaskIntoConstraints = NO;.它出现在最外层"UIView — 视图层次结构根部的超级视图必须使用默认的 translatesAutoresizingMaskIntoConstraints = YES.一旦我删除了它，一切都按预期工作.

I was setting translatesAutoresizingMaskIntoConstraints = NO; on my root UIView. It appears the "outermost" UIView — the superview at the root of your view hierarchy must use the default translatesAutoresizingMaskIntoConstraints = YES. Once I've removed this, everything worked as expected.