title: C# Error "Is not supported by the language" after migration to .Net4
body: <p>I'm trying to migration our website from .Net 3.5 to 4 and I'm encountering a very weird issue.</p>
  
  <p>Code that works just fine in 3.5 does not anymore once I target .Net4, giving me the error </p>
  
  <blockquote>
    <p>"xxx is not supported by the language".</p>
  </blockquote>
  
  <pre><code>TimeZoneInfo tzi = !calendarItem.UseUserTimeZone ? user.Settings.TimeZoneInfo : l.TimeZoneItem.Info;
  </code></pre>
  
  <p>On that line of code the error shows on "<code>.TimeZoneInfo</code>" and "<code>.Info</code>" both of type "<code>System.TimeZoneInfo</code>".</p>
  
  <p>Definition of <code>user.Settings.TimeZoneInfo</code> property is:</p>
  
  <pre><code>public TimeZoneInfo TimeZoneInfo
  {
      get { return World.TimeZones[Convert.ToInt32(this[Setting.TimeZoneInfo])].Info; }
      set { this[Setting.TimeZoneInfo] = value.ToTimeZoneItem().Id.ToString(); }
  }
  </code></pre>
  
  <p>Definition of <code>l.TimeZoneItem.Info</code> property is:</p>
  
  <pre><code>public TimeZoneInfo Info
  {
      get { return info; }
  }
  </code></pre>
  
  <p>Not really sure what's going on here. Need help on that one please.</p>