Function trait_predicate_with_def_id

fn trait_predicate_with_def_id<I: Interner>(
    cx: I,
    clause: Binder<I, TraitPredicate<I>>,
    did: I::DefId,
) -> I::Clause

Small helper function to change the def_id of a trait predicate - this is not normally something that you want to do, as different traits will require different args and so making it easy to change the trait is something of a footgun, but it is useful in the narrow circumstance of changing from MetaSized to Sized, which happens as part of the lazy elaboration of sizedness candidates.