Function is_nonnull_new_unchecked 

pub(crate) fn is_nonnull_new_unchecked(callee: Option<DefId>) -> bool

Whether callee is NonNull::new_unchecked (the unchecked transparent wrapper). Modeled as a provenance-preserving alias so the pointer’s element offset survives inlined iterator bodies (post_inc_start’s new_unchecked(ptr.add(1))); non-nullness is inherited from the source, not asserted, so new_unchecked(null) unsoundness is still caught.