C# 'is' type check on struct - odd .NET 4.0 x86 optimization behavior

Question

Update: I have filed a bug report with Microsoft Connect, please vote for it!

Update 2: Microsoft have marked the bug report as fixed

Answer 1

That's not cool. I think you should file a bug. (connect.microsoft.com)

Also, this seems to work (I only tested for your fail case though):

    public static bool IsGuid(object item)
    {
        return item.GetType() == typeof(Guid);
    }