List.merge.go: def of Base
Import: import Base
Lines 1150-1170 of Base/base.bend: https://jend.leeeet.dev/read.txt?path=Base/base.bend&start_line=1150&end_line=1170

import Base

# The fuel bounds the steps: a sort passes its length, enough for any merge.
def List.merge.go(
  ~A: Data, ~le: A -> A -> Bool, fuel: Nat,
  st: List<&2, A> & List<&2, A> & List<&2, A>
) -> List<&2, A>:
  match fuel:
    case 0n:
      (acc, xs, ys) = st
      List.reverse.go(&2, A, acc, List.append(&2, A, xs, ys))
    case 1n+f:
      (acc, xs, ys) = st
      match xs ys:
        case Nil{} Nil{}:
          List.reverse.go(&2, A, acc, Nil{})
        case Nil{} y <> yt:
          List.reverse.go(&2, A, acc, y <> yt)
        case x <> xt Nil{}:
          List.reverse.go(&2, A, acc, x <> xt)
        case +x <> xt +y <> yt:
          List.merge.go(~A, ~le, f,
            List.merge.step(A, acc, x, xt, y, yt, le(x, y)))

Uses (8):
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Bool
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=List
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=List.append
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=List.merge.step
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=List.reverse.go
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Nat
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Pair
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Sigma