title: C# error CS0117: 'Array' does not contain a definition for
body: <p>I am trying to use <code>Array.Fill</code> in my program but I am getting an error saying that there is no definition for <code>Fill</code>. I left off the function name in the title of this post because the same problem seems to happen for multiple functions in <code>Array</code>. I found multiple forum posts online where people had the same problem and for them the solution was to add <code>using System;</code> or <code>using System.Linq;</code>, but I already have both of these. I suspect the problem is that I need to somehow add the assembly <code>System.Runtime.dll</code> which contains the definition for <code>Array.Fill</code>, but I am using Unity with Visual Studio for Mac and I have not been able to find a way to manage assemblies in either program. I have also been unable to find a project or solution file anywhere (I believe that is where I would add an assembly). Here is the problem line:</p>
  <pre><code>Array.Fill&lt;Vector4&gt;(cross, Rot4.Cross(vs[0], vs[1], vs[2]));
  </code></pre>
  <p>Does anyone have any idea what I can try? I suppose I could fill my array manually, but I want to know why this isn't working.</p>