Function rustc_trait_selection::infer::unify_key::replace_if_possible

pub fn replace_if_possible<'tcx, V, L>(
    table: &mut UnificationTable<InPlace<ConstVid, V, L>>, 
    c: &Const
) -> &Const where
    V: VecLike<Delegate<ConstVid>>,
    L: UndoLogs<UndoLog<Delegate<ConstVid>>>,