Contract for Enum.GetName incorrectly states result not null

[NameOfTheDragon]

When building I get an incorrect warning about possible 'dead code' for the following IF statement:

            foreach (char c in text)
                {
                var b = (byte)c;
                var strASCII = Enum.GetName(typeof(AsciiSymbols), b);
                if (strASCII != null)
                    expanded.Append("<" + strASCII + ">");
                else
                    expanded.Append(c);
                }

The problem seems to be an incorrect contract for Enum.GetName():

An examination of the source code shows that the result can in fact be null, so this is leading to a false positive in the warning.