How to create a List of Structs?

I’m trying to create a List of structs, called _warnings, which only has three member variables of its own:

private			List<Warning>	_warnings = new List<Warning>( );

When I try to add a warning to this List:

Warning w = new Warning
{
    TimeDisplayed	= 0f,
	TotalTime	= displayTime,
	Message		= s
};
_warnings.Add( w );

and try to run it, at runtime it will tell me that the type is unknown:

alt text

Does anyone know why I cannot add something to this List?
And yes, I did import the List namespace :wink:

Looks like this is a bug in Mono. The patch notes for Mono 2.10.2 list:

  • 679586: Unknown type System.Collections.Generic.CollectionDebuggerView error when viewing Parametrized collection in debugger

A quick check on my copy of Unity says that Unity 4.0.0f7 uses Mono 2.0 (or at least it does on my machine).