Monoid for ZipList

As instance Alternative ZipList is defined since 4.11.0.0: instanceAlternativeZipListwhereempty=ZipList[]ZipList<|>ZipList=ZipList(xs++drop(lengthxs)ys) It seems perfectly fine to make Monoid for ZipList as followings: instance Semigroup a => Semigroup (ZipList a) where ZipList [] <> ZipList ys = ZipList ys ZipList xs <> ZipList [] = ZipList xs ZipList (x:xs) <> ZipList (y:ys) = ZipList (x <> y : ZipList xs <> ZipList ys) instance Semigroup a => Monoid (ZipList a) where mempty = ZipList [] Note that this semantic is similar to that of Maybe​.