should repositories exercise iqueryable<t>?

i'm deliberation twin irepository interfaces, heir iqueryable contains iqueryable.

like this:

public interface irepository<t> : iqueryable<t>
{
    t save(t entity);
    vacant delete(t entity);
}

or this:

public interface irepository<t>
{
    t save(t entity);
    vacant delete(t entity);
    iqueryable<t> query();
}

linq use be:

from dos
in servicelocator.current.getinstance<irepository<domainobject>>()
where dos.id == id
select dos

or...

from dos
in servicelocator.current.getinstance<irepository<domainobject>>().query
where dos.id == id
select dos

i kinda initial one, nonetheless it's mysterious mock. have implemented linqable, mockable repositories?

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