Default value ILookup<> in loose mode is null

[ggirard07]

Based on wiki, and as ILookup<> inherits from IEnumerable<>, I would expect the default value in loose mode to be an empty lookup, not null.

returns default values or empty arrays, enumerables, etc

Am I missing something here?

[stakx]

Hi @ggirard07, IIRC the code behind DefaultValue.Empty performs a strict type check and doesn't take type inheritance into account.

Before you ask: yes, of course this could be changed. We've had similar requests in the past. (If I find the time, I'll link to some of them later.) However, I have been hesitant to change the behavior of DefaultValue.Empty because it is a core part of Moq and functional changes to it it could affect much pre-existing user code.

Now that Moq vNext has been shelved (for the time being) and we're free to do a new major version, perhaps we'll be able to change that behavior in v5.