string.Concat(object) is the only overload returning null if Object.ToString is null

[jamesqo]

Title basically says it all. All the other Concat/Join overloads in String return string.Empty for null inputs, however this is not the case with Concat(object):

public static String Concat(Object arg0) {
    Contract.Ensures(Contract.Result<String>() != null);
    Contract.EndContractBlock();

    if (arg0 == null)
    {
        return String.Empty;
    }
    return arg0.ToString();
}

If ToString returns null then Concat will return null. This is in contrast to basically all of the other overloads, which return string.Empty for null inputs.

Link to source code

Maybe this should be fixed?

[jamesqo]

Closing, as the associated PR to fix was closed.