title: Contraints greyed-out in Xcode
body: <p>I am trying to debug+understand autolayout constraints and I notice that when debugging the view with xcode (using the cool layer thing) I noticed that on one element in the view the constraints look like this</p>
  
  <p><img src="https://i.stack.imgur.com/KwavX.png" alt="enter image description here"></p>
  
  <p>and the view is indeed ignoring these constraints. </p>
  
  <p>All constraints have the same priority (1000) since I want them all. All constraints were made with interface builder and not through code, and there are not warning or conflicts in IB.</p>
  
  <p>But in runtime I do see this </p>
  
  <pre><code>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. (Note: If you're seeing NSAutoresizingMaskLayoutConstraints that you don't understand, refer to the documentation for the UIView property translatesAutoresizingMaskIntoConstraints) 
  (
      "&lt;NSLayoutConstraint:0x79684f10 V:[UIImageView:0x79686800(&gt;=160)]&gt;",
      "&lt;NSLayoutConstraint:0x7968a310 V:[UIImageView:0x79686800]-(130.5)-|   (Names: '|':UIView:0x79686790 )&gt;",
      "&lt;NSLayoutConstraint:0x7968a340 V:|-(0)-[UIImageView:0x79686800]   (Names: '|':UIView:0x79686790 )&gt;",
      "&lt;NSLayoutConstraint:0x796997b0 'UIView-Encapsulated-Layout-Height' V:[CoverCell:0x79686570(192)]&gt;",
      "&lt;NSAutoresizingMaskLayoutConstraint:0x7969cd30 h=-&amp;- v=-&amp;- UIView:0x79686790.height == CoverCell:0x79686570.height&gt;"
  )
  
  Will attempt to recover by breaking constraint 
  &lt;NSLayoutConstraint:0x79684f10 V:[UIImageView:0x79686800(&gt;=160)]&gt;
  </code></pre>
  
  <p>So from this I understand that some rules conflict, but I'm not sure how to read this</p>
  
  <p>the <code>&gt;=160</code> is a rule on the UIImageView so it would have height of atleast 160 and 130.5 is the bottom padding of the imageview (so when using <code>systemLayoutSizeFittingSize:UILayoutFittingCompressedSize</code> the height won't be 0. So the minimum height for the entire cell is 160+130.5)</p>
  
  <p>The rest of the error I don't understand.</p>
  
  <p>What is wrong with the constraints and why do constraint conflicts occur in runtime and not in IB?</p>