case next bm m' =>
cases bn <;> cases bm <;> simp [addfull] at *
case false.false =>
match h': addfull n' m' with
| .next br r =>
rw [h'] at h
cases br <;> simp [bne, toSint] at * <;> sorry_arith
case false.true =>
match h': addfull n' m' with
| .next br r =>
rw [h'] at h
cases br <;> simp [bne, BEq.beq, toSint] at * <;> sorry_arith
case true.false =>
match h': addfull n' m' with
| .next br r =>
rw [h'] at h
cases br <;> simp [bne, BEq.beq, toSint] at * <;> sorry_arith
case true.true =>
match h': addfull n' m' with
| .next br r =>
rw [h'] at h
cases br <;> simp [bne, toSint] at * <;> sorry_arith
sz : ℕ
bn : Bool
n' : FinInt sz
bm : Bool
m' : FinInt sz
h :
  toSint (addfull (next bn n') (next bm m')) =
    match next bn n', next bm m' with
    | next false n'_1, next false m'_1 => toSint (next bn n') + toSint (next bm m')
    | next false n'_1, next true m'_1 =>
      match addfull (next bn n') (next bm m') with
      | next false a => toSint (next bn n') + toSint (next bm m') + 2 ^ (sz + 1)
      | next true a => toSint (next bn n') + toSint (next bm m') - 2 ^ (sz + 1)
    | next true n'_1, next false m'_1 =>
      match addfull (next bn n') (next bm m') with
      | next false a => toSint (next bn n') + toSint (next bm m') + 2 ^ (sz + 1)
      | next true a => toSint (next bn n') + toSint (next bm m') - 2 ^ (sz + 1)
    | next true n'_1, next true m'_1 => toSint (next bn n') + toSint (next bm m')
⊢ toSint (next bn n' + next bm m') =
    match next bn n', next bm m' with
    | next false n'_1, next false m'_1 =>
      match next bn n' + next bm m' with
      | next false a => toSint (next bn n') + toSint (next bm m')
      | next true a => toSint (next bn n') + toSint (next bm m') - 2 ^ (sz + 1)
    | next false n'_1, next true m'_1 => toSint (next bn n') + toSint (next bm m')
    | next true n'_1, next false m'_1 => toSint (next bn n') + toSint (next bm m')
    | next true n'_1, next true m'_1 =>
      match next bn n' + next bm m' with
      | next false a => toSint (next bn n') + toSint (next bm m') + 2 ^ (sz + 1)
      | next true a => toSint (next bn n') + toSint (next bm m')
no goals