Co-variant array conversion from x to y may cause run-time exception

Question

I have a private readonly list of LinkLabels (IList). I later add LinkLabels to this list and add those

Answer 1

With VS 2008, I am not getting this warning. This must be new to .NET 4.0.
Clarification: according to Sam Mackrill it's Resharper who displays a warning.

The C# compiler does not know that AddRange will not modify the array passed to it. Since AddRange has a parameter of type Control[], it could in theory try to assign a TextBox to the array, which would be perfectly correct for a true array of Control, but the array is in reality an array of LinkLabels and will not accept such an assignment.

Making arrays co-variant in c# was a bad decision of Microsoft. While it might seem a good idea to be able to assign an array of a derived type to an array of a base type in the first place, this can lead to runtime errors!