Function rustc_middle::ty::context::tls::set_tlv

pub(in ty::context::tls) fn set_tlv<F: FnOnce() -> R, R>(
    value: usize, 
    f: F
) -> R

Sets TLV to value during the call to f. It is restored to its previous value after. This is used to set the pointer to the new ImplicitCtxt.