Function callee_guards_recipient 

fn callee_guards_recipient<'hir>(
    gcx: Gcx<'hir>,
    hir: &'hir Hir<'hir>,
    function_id: FunctionId,
    args: &'hir CallArgs<'hir>,
    recipient: VariableId,
    token: VariableId,
    bypass: bool,
    seen: &mut Vec<FunctionId>,
) -> GuardCoverage

A call handing the checked identities to a same-frame function or modifier whose body proves acceptance for the parameters they land on. Callback guards receive distinct recipient and token identities; the recipient-only pass supplies the same identity in both slots, allowing an address-only helper to prove that it has no code. Arguments are matched by is_exactly_var against the callee’s parameters and by parameter name for named arguments.