Bug 794 - Delegate.CreateDelegate does not support Enum casting
Summary: Delegate.CreateDelegate does not support Enum casting
Status: RESOLVED FIXED
Alias: None
Product: Class Libraries
Classification: Mono
Component: mscorlib ()
Version: 2.10.x
Hardware: PC Windows
: --- minor
Target Milestone: Untriaged
Assignee: Bugzilla
URL:
Depends on:
Blocks:
 
Reported: 2011-09-13 17:23 UTC by Michael Burbea
Modified: 2012-01-06 18:42 UTC (History)
4 users (show)

Tags:
Is this bug a regression?: ---
Last known good build:

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Status:
RESOLVED FIXED

Description Michael Burbea 2011-09-13 17:23:30 UTC
The following is legal in the .NET runtime but throws an exception in mono. 
I asked on microsoft's feedback if this behavior was acceptable and they actually consider it not a bug. To maintain compatibility Mono should also have this "feature".

https://connect.microsoft.com/VisualStudio/feedback/details/614234/delegate-createdelegate-allows-binding-functions-with-enum-parameters-to-the-enum-base-type

Example code:
public static class Program
{
		private static Func<Int32, Int32, bool> Int32D = (x, y) => (x & y) == y;

		private static Func<StringComparison, StringComparison, bool> StringComparisonD =
			Delegate.CreateDelegate(typeof (Func<StringComparison, StringComparison, bool>), Int32D.Method) as
			Func<StringComparison, StringComparison, bool>; 
		static void Main()
		{
                   Console.Write(StringComparisonD(0,0));
                }
}
On the CLR this code executes, in mono it throws an ArgumentException.
Comment 1 Mikayla Hutchinson [MSFT] 2011-09-13 17:48:39 UTC
FWIW I wouldn't read MS' answer as "not a bug", but rather "not a big deal and fixing would break back-compat". But Mono should probably do the same thing for the sake of compatibility.
Comment 2 Zoltan Varga 2012-01-06 18:42:59 UTC
Fixed in HEAD/2.10 branch.