istUnionRight :: (Ord a) => [a] -> [a] -> [a]
listUnionRight a b = ordNubRight (filter (`Set.notMember` bSet) a) ++ b
  where
    bSet = Set.fromList b

-- | A total variant of 'tail'.

listUnionRight :: (Ord a) => [a] -> [a] -> [a]
listUnionRight a b = ordNubRight (filter (`Set.notMember` bSet) a) ++ b
  where
    bSet = Set.fromList b

-- | A total variant of 'tail'.
listUnionRight a b = ordNubRight (filter (`Set.notMember` bSet) a) ++ b
  where
    bSet = Set.fromList b

-- | A total variant of 'tail'.