(motive : String.Pos.Raw × Lean.Parser.SyntaxStack × Lean.Parser.Error → Sort u_1) →
  (x : String.Pos.Raw × Lean.Parser.SyntaxStack × Lean.Parser.Error) →
    ((pos : String.Pos.Raw) → (stk : Lean.Parser.SyntaxStack) → (err : Lean.Parser.Error) → motive (pos, stk, err)) →
      motive x