System.ArgumentNullException: Argument cannot be null.
Parameter name: type
  at MonoDevelop.Projects.Dom.Parser.ProjectDom+<GetInheritanceTree>c__Iterator33.MoveNext () [0x0023d] in /private/tmp/source/monodevelop/main/src/core/MonoDevelop.Core/MonoDevelop.Projects.Dom.Parser/ProjectDom.cs:164 
  at MonoDevelop.MacDev.ObjCIntegration.NSObjectProjectInfo.ResolveCliToObjc (MonoDevelop.MacDev.ObjCIntegration.NSObjectTypeInfo type) [0x000fb] in /private/tmp/source/monodevelop/main/src/addins/MonoDevelop.MacDev/ObjCIntegration/NSObjectProjectInfo.cs:182 
  at MonoDevelop.MacDev.ObjCIntegration.NSObjectProjectInfo.Update () [0x000fe] in /private/tmp/source/monodevelop/main/src/addins/MonoDevelop.MacDev/ObjCIntegration/NSObjectProjectInfo.cs:89 
  at MonoDevelop.MacDev.ObjCIntegration.NSObjectProjectInfo.Update (Boolean force) [0x0000c] in /private/tmp/source/monodevelop/main/src/addins/MonoDevelop.MacDev/ObjCIntegration/NSObjectProjectInfo.cs:66 
  at MonoDevelop.MacDev.XcodeSyncing.XcodeProjectTracker.UpdateTypes (IProgressMonitor monitor, Boolean force) [0x00034] in /private/tmp/source/monodevelop/main/src/addins/MonoDevelop.MacDev/XcodeSyncing/XcodeProjectTracker.cs:307