@[irreducible]

def Subarray.mergeSort {α : Type u_1} (xs : Subarray α) (le : α → α → Bool := by exact (· ≤ ·)) : Array α

@[inline]

def Array.mergeSort {α : Type u_1} (xs : Array α) (le : α → α → Bool := by exact (· ≤ ·)) : Array α