Too many constructors with 1 parameters. The behaviour is unpredictable
<p>Out of seemingly nowhere, ReSharper started reporting this warning in all my <code>.xaml</code> files:</p>

<p><code>Too many constructors with 1 parameters. The behaviour is unpredictable</code></p>

<p><a href="https://i.stack.imgur.com/qo0Gn.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/qo0Gn.png" alt="enter image description here"></a></p>

<p>It seems that every use of <code>{x:Type}</code> in my project is now causing this warning. I've tried the following things to clear the warning--all to no avail:</p>

<ul>
<li>Removing a recently-added NuGet package</li>
<li>Clearing my ReSharper cache</li>
<li>Clean/Rebuild solution</li>
</ul>

<p>I should note that my project builds and runs just fine. I am stumped. What's going on here?</p>