mathlib commit https://github.com/leanprover-community/mathlib/commit/65a1391a0106c9204fe45bc73a039f056558cb83

@@ -3,7 +3,7 @@ Copyright (c) 2022 Eric Rodriguez. All rights reserved.
 Released under Apache 2.0 license as described in the file LICENSE.
 Authors: Eric Rodriguez
 -/
-import Algebra.BigOperators.Order
+import Algebra.Order.BigOperators.Group.Finset
 import Data.Fintype.BigOperators
 import Data.Int.Lemmas
 import Tactic.DeriveFintype

mathlib commit https://github.com/leanprover-community/mathlib/commit/65a1391a0106c9204fe45bc73a039f056558cb83

@@ -557,7 +557,7 @@ theorem sign_eq_sign (n : ℤ) : n.sign = SignType.sign n :=
   by
   obtain (_ | _) | _ := n
   · exact congr_arg coe sign_zero.symm
-  · exact congr_arg coe (sign_pos <| Int.succ_coe_nat_pos _).symm
+  · exact congr_arg coe (sign_pos <| Int.succ_natCast_pos _).symm
   · exact congr_arg coe (_root_.sign_neg <| neg_succ_lt_zero _).symm
 #align int.sign_eq_sign Int.sign_eq_sign
 -/

mathlib commit https://github.com/leanprover-community/mathlib/commit/65a1391a0106c9204fe45bc73a039f056558cb83

@@ -375,8 +375,8 @@ theorem sign_eq_one_iff : SignType.sign a = 1 ↔ 0 < a :=
   by
   refine' ⟨fun h => _, fun h => sign_pos h⟩
   by_contra hn
-  rw [sign_apply, if_neg hn] at h 
-  split_ifs at h  <;> simpa using h
+  rw [sign_apply, if_neg hn] at h
+  split_ifs at h <;> simpa using h
 #align sign_eq_one_iff sign_eq_one_iff
 -/
 
@@ -384,8 +384,8 @@ theorem sign_eq_one_iff : SignType.sign a = 1 ↔ 0 < a :=
 theorem sign_eq_neg_one_iff : SignType.sign a = -1 ↔ a < 0 :=
   by
   refine' ⟨fun h => _, fun h => sign_neg h⟩
-  rw [sign_apply] at h 
-  split_ifs at h 
+  rw [sign_apply] at h
+  split_ifs at h
   · simpa using h
   · exact h_2
   · simpa using h
@@ -403,8 +403,8 @@ variable [Zero α] [LinearOrder α] {a : α}
 theorem sign_eq_zero_iff : SignType.sign a = 0 ↔ a = 0 :=
   by
   refine' ⟨fun h => _, fun h => h.symm ▸ sign_zero⟩
-  rw [sign_apply] at h 
-  split_ifs at h  <;> cases h
+  rw [sign_apply] at h
+  split_ifs at h <;> cases h
   exact (le_of_not_lt h_1).eq_of_not_lt h_2
 #align sign_eq_zero_iff sign_eq_zero_iff
 -/

mathlib commit https://github.com/leanprover-community/mathlib/commit/65a1391a0106c9204fe45bc73a039f056558cb83

@@ -316,7 +316,9 @@ def castHom {α} [MulZeroOneClass α] [HasDistribNeg α] : SignType →*₀ α
 -/
 
 #print SignType.range_eq /-
-theorem range_eq {α} (f : SignType → α) : Set.range f = {f zero, f neg, f pos} := by classical
+theorem range_eq {α} (f : SignType → α) : Set.range f = {f zero, f neg, f pos} := by
+  classical simpa only [← Finset.coe_singleton, ← Finset.image_singleton, ← Fintype.coe_image_univ,
+    Finset.coe_image, ← Set.image_insert_eq]
 #align sign_type.range_eq SignType.range_eq
 -/
 

mathlib commit https://github.com/leanprover-community/mathlib/commit/65a1391a0106c9204fe45bc73a039f056558cb83

@@ -316,9 +316,7 @@ def castHom {α} [MulZeroOneClass α] [HasDistribNeg α] : SignType →*₀ α
 -/
 
 #print SignType.range_eq /-
-theorem range_eq {α} (f : SignType → α) : Set.range f = {f zero, f neg, f pos} := by
-  classical simpa only [← Finset.coe_singleton, ← Finset.image_singleton, ← Fintype.coe_image_univ,
-    Finset.coe_image, ← Set.image_insert_eq]
+theorem range_eq {α} (f : SignType → α) : Set.range f = {f zero, f neg, f pos} := by classical
 #align sign_type.range_eq SignType.range_eq
 -/
 

mathlib commit https://github.com/leanprover-community/mathlib/commit/ce64cd319bb6b3e82f31c2d38e79080d377be451

@@ -3,10 +3,10 @@ Copyright (c) 2022 Eric Rodriguez. All rights reserved.
 Released under Apache 2.0 license as described in the file LICENSE.
 Authors: Eric Rodriguez
 -/
-import Mathbin.Algebra.BigOperators.Order
-import Mathbin.Data.Fintype.BigOperators
-import Mathbin.Data.Int.Lemmas
-import Mathbin.Tactic.DeriveFintype
+import Algebra.BigOperators.Order
+import Data.Fintype.BigOperators
+import Data.Int.Lemmas
+import Tactic.DeriveFintype
 
 #align_import data.sign from "leanprover-community/mathlib"@"e46da4e335b8671848ac711ccb34b42538c0d800"
 

mathlib commit https://github.com/leanprover-community/mathlib/commit/32a7e535287f9c73f2e4d2aef306a39190f0b504

@@ -126,8 +126,8 @@ instance : BoundedOrder SignType where
 instance : HasDistribNeg SignType :=
   { SignType.hasNeg with
     neg_neg := fun x => by cases x <;> rfl
-    neg_mul := fun x y => by casesm*_ <;> rfl
-    mul_neg := fun x y => by casesm*_ <;> rfl }
+    neg_hMul := fun x y => by casesm*_ <;> rfl
+    hMul_neg := fun x y => by casesm*_ <;> rfl }
 
 #print SignType.fin3Equiv /-
 /-- `sign_type` is equivalent to `fin 3`. -/

mathlib commit https://github.com/leanprover-community/mathlib/commit/63721b2c3eba6c325ecf8ae8cca27155a4f6306f

@@ -74,19 +74,19 @@ instance : Mul SignType :=
     | zero => zero
     | Pos => y⟩
 
-#print SignType.Le /-
+#print SignType.LE /-
 /-- The less-than relation on signs. -/
-inductive Le : SignType → SignType → Prop
+inductive LE : SignType → SignType → Prop
   | of_neg (a) : le neg a
   | zero : le zero zero
   | of_pos (a) : le a pos
-#align sign_type.le SignType.Le
+#align sign_type.le SignType.LE
 -/
 
 instance : LE SignType :=
-  ⟨Le⟩
+  ⟨LE⟩
 
-instance : DecidableRel Le := fun a b => by
+instance : DecidableRel LE := fun a b => by
   cases a <;> cases b <;>
     first
     | exact is_false (by rintro ⟨⟩)
@@ -115,13 +115,13 @@ instance : LinearOrder SignType where
   le_total a b := by casesm*_ <;> decide
   le_antisymm a b ha hb := by casesm*_ <;> rfl
   le_trans a b c hab hbc := by casesm*_ <;> constructor
-  decidableLe := Le.decidableRel
+  decidableLe := LE.decidableRel
 
 instance : BoundedOrder SignType where
   top := 1
-  le_top := Le.of_pos
+  le_top := LE.of_pos
   bot := -1
-  bot_le := Le.of_neg
+  bot_le := LE.of_neg
 
 instance : HasDistribNeg SignType :=
   { SignType.hasNeg with

mathlib commit https://github.com/leanprover-community/mathlib/commit/8ea5598db6caeddde6cb734aa179cc2408dbd345

@@ -2,17 +2,14 @@
 Copyright (c) 2022 Eric Rodriguez. All rights reserved.
 Released under Apache 2.0 license as described in the file LICENSE.
 Authors: Eric Rodriguez
-
-! This file was ported from Lean 3 source module data.sign
-! leanprover-community/mathlib commit e46da4e335b8671848ac711ccb34b42538c0d800
-! Please do not edit these lines, except to modify the commit id
-! if you have ported upstream changes.
 -/
 import Mathbin.Algebra.BigOperators.Order
 import Mathbin.Data.Fintype.BigOperators
 import Mathbin.Data.Int.Lemmas
 import Mathbin.Tactic.DeriveFintype
 
+#align_import data.sign from "leanprover-community/mathlib"@"e46da4e335b8671848ac711ccb34b42538c0d800"
+
 /-!
 # Sign function
 

mathlib commit https://github.com/leanprover-community/mathlib/commit/9240e8be927a0955b9a82c6c85ef499ee3a626b8

@@ -582,7 +582,7 @@ private theorem exists_signed_sum_aux [DecidableEq α] (s : Finset α) (f : α 
       SignType.sign (f a.1), fun a => a.1, fun a => a.1.Prop, _, _⟩
   · simp [@sum_attach _ _ _ _ fun a => (f a).natAbs]
   · intro x hx
-    simp [sum_sigma, hx, ← Int.sign_eq_sign, Int.sign_mul_abs, mul_comm (|f _|),
+    simp [sum_sigma, hx, ← Int.sign_eq_sign, Int.sign_mul_abs, mul_comm |f _|,
       @sum_attach _ _ _ _ fun a => ∑ j in range (f a).natAbs, if a = x then (f a).sign else 0]
 
 #print exists_signed_sum /-

mathlib commit https://github.com/leanprover-community/mathlib/commit/9fb8964792b4237dac6200193a0d533f1b3f7423

@@ -166,8 +166,10 @@ theorem nonneg_iff_ne_neg_one {a : SignType} : 0 ≤ a ↔ a ≠ -1 := by decide
 #align sign_type.nonneg_iff_ne_neg_one SignType.nonneg_iff_ne_neg_one
 -/
 
+#print SignType.neg_one_lt_iff /-
 theorem neg_one_lt_iff {a : SignType} : -1 < a ↔ 0 ≤ a := by decide!
 #align sign_type.neg_one_lt_iff SignType.neg_one_lt_iff
+-/
 
 #print SignType.nonpos_iff /-
 theorem nonpos_iff {a : SignType} : a ≤ 0 ↔ a = -1 ∨ a = 0 := by decide!
@@ -179,12 +181,16 @@ theorem nonpos_iff_ne_one {a : SignType} : a ≤ 0 ↔ a ≠ 1 := by decide!
 #align sign_type.nonpos_iff_ne_one SignType.nonpos_iff_ne_one
 -/
 
+#print SignType.lt_one_iff /-
 theorem lt_one_iff {a : SignType} : a < 1 ↔ a ≤ 0 := by decide!
 #align sign_type.lt_one_iff SignType.lt_one_iff
+-/
 
+#print SignType.neg_iff /-
 @[simp]
 theorem neg_iff {a : SignType} : a < 0 ↔ a = -1 := by decide!
 #align sign_type.neg_iff SignType.neg_iff
+-/
 
 #print SignType.le_neg_one_iff /-
 @[simp]
@@ -193,9 +199,11 @@ theorem le_neg_one_iff {a : SignType} : a ≤ -1 ↔ a = -1 :=
 #align sign_type.le_neg_one_iff SignType.le_neg_one_iff
 -/
 
+#print SignType.pos_iff /-
 @[simp]
 theorem pos_iff {a : SignType} : 0 < a ↔ a = 1 := by decide!
 #align sign_type.pos_iff SignType.pos_iff
+-/
 
 #print SignType.one_le_iff /-
 @[simp]
@@ -218,15 +226,19 @@ theorem le_one (a : SignType) : a ≤ 1 :=
 #align sign_type.le_one SignType.le_one
 -/
 
+#print SignType.not_lt_neg_one /-
 @[simp]
 theorem not_lt_neg_one (a : SignType) : ¬a < -1 :=
   not_lt_bot
 #align sign_type.not_lt_neg_one SignType.not_lt_neg_one
+-/
 
+#print SignType.not_one_lt /-
 @[simp]
 theorem not_one_lt (a : SignType) : ¬1 < a :=
   not_top_lt
 #align sign_type.not_one_lt SignType.not_one_lt
+-/
 
 #print SignType.self_eq_neg_iff /-
 @[simp]
@@ -240,10 +252,12 @@ theorem neg_eq_self_iff (a : SignType) : -a = a ↔ a = 0 := by decide!
 #align sign_type.neg_eq_self_iff SignType.neg_eq_self_iff
 -/
 
+#print SignType.neg_one_lt_one /-
 @[simp]
 theorem neg_one_lt_one : (-1 : SignType) < 1 :=
   bot_lt_top
 #align sign_type.neg_one_lt_one SignType.neg_one_lt_one
+-/
 
 end CaseBashing
 
@@ -292,6 +306,7 @@ theorem coe_neg_one : ↑(-1 : SignType) = (-1 : α) :=
 
 end cast
 
+#print SignType.castHom /-
 /-- `sign_type.cast` as a `mul_with_zero_hom`. -/
 @[simps]
 def castHom {α} [MulZeroOneClass α] [HasDistribNeg α] : SignType →*₀ α
@@ -301,6 +316,7 @@ def castHom {α} [MulZeroOneClass α] [HasDistribNeg α] : SignType →*₀ α
   map_one' := rfl
   map_mul' x y := by cases x <;> cases y <;> simp
 #align sign_type.cast_hom SignType.castHom
+-/
 
 #print SignType.range_eq /-
 theorem range_eq {α} (f : SignType → α) : Set.range f = {f zero, f neg, f pos} := by
@@ -319,6 +335,7 @@ section Preorder
 
 variable [Zero α] [Preorder α] [DecidableRel ((· < ·) : α → α → Prop)] {a : α}
 
+#print SignType.sign /-
 /-- The sign of an element is 1 if it's positive, -1 if negative, 0 otherwise. -/
 def SignType.sign : α →o SignType :=
   ⟨fun a => if 0 < a then 1 else if a < 0 then -1 else 0, fun a b h =>
@@ -329,6 +346,7 @@ def SignType.sign : α →o SignType :=
     · cases h₂ (h₁.trans_le h)
     · cases h₄ (h.trans_lt h₃)⟩
 #align sign SignType.sign
+-/
 
 #print sign_apply /-
 theorem sign_apply : SignType.sign a = ite (0 < a) 1 (ite (a < 0) (-1) 0) :=
@@ -428,10 +446,12 @@ section OrderedSemiring
 
 variable [OrderedSemiring α] [DecidableRel ((· < ·) : α → α → Prop)] [Nontrivial α]
 
+#print sign_one /-
 @[simp]
 theorem sign_one : SignType.sign (1 : α) = 1 :=
   sign_pos zero_lt_one
 #align sign_one sign_one
+-/
 
 end OrderedSemiring
 
@@ -443,13 +463,16 @@ variable [LinearOrderedRing α] {a b : α}
 113488-general/topic/type.20class.20inference.20issues/near/276937942 -/
 attribute [local instance] LinearOrderedRing.decidableLt
 
+#print sign_mul /-
 theorem sign_mul (x y : α) : SignType.sign (x * y) = SignType.sign x * SignType.sign y := by
   rcases lt_trichotomy x 0 with (hx | hx | hx) <;> rcases lt_trichotomy y 0 with (hy | hy | hy) <;>
     simp only [sign_zero, MulZeroClass.mul_zero, MulZeroClass.zero_mul, sign_pos, sign_neg, hx, hy,
       mul_one, neg_one_mul, neg_neg, one_mul, mul_pos_of_neg_of_neg, mul_neg_of_neg_of_pos,
       neg_zero, mul_neg_of_pos_of_neg, mul_pos]
 #align sign_mul sign_mul
+-/
 
+#print signHom /-
 /-- `sign` as a `monoid_with_zero_hom` for a nontrivial ordered semiring. Note that linearity
 is required; consider ℂ with the order `z ≤ w` iff they have the same imaginary part and
 `z - w ≤ 0` in the reals; then `1 + i` and `1 - i` are incomparable to zero, and thus we have:
@@ -460,12 +483,15 @@ def signHom : α →*₀ SignType where
   map_one' := sign_one
   map_mul' := sign_mul
 #align sign_hom signHom
+-/
 
+#print sign_pow /-
 theorem sign_pow (x : α) (n : ℕ) : SignType.sign (x ^ n) = SignType.sign x ^ n :=
   by
   change signHom (x ^ n) = signHom x ^ n
   exact map_pow _ _ _
 #align sign_pow sign_pow
+-/
 
 end LinearOrderedRing
 
@@ -473,6 +499,7 @@ section AddGroup
 
 variable [AddGroup α] [Preorder α] [DecidableRel ((· < ·) : α → α → Prop)]
 
+#print Left.sign_neg /-
 theorem Left.sign_neg [CovariantClass α α (· + ·) (· < ·)] (a : α) :
     SignType.sign (-a) = -SignType.sign a :=
   by
@@ -483,7 +510,9 @@ theorem Left.sign_neg [CovariantClass α α (· + ·) (· < ·)] (a : α) :
   · simp
   · simp
 #align left.sign_neg Left.sign_neg
+-/
 
+#print Right.sign_neg /-
 theorem Right.sign_neg [CovariantClass α α (Function.swap (· + ·)) (· < ·)] (a : α) :
     SignType.sign (-a) = -SignType.sign a :=
   by
@@ -494,6 +523,7 @@ theorem Right.sign_neg [CovariantClass α α (Function.swap (· + ·)) (· < ·)
   · simp
   · simp
 #align right.sign_neg Right.sign_neg
+-/
 
 end AddGroup
 
@@ -507,6 +537,7 @@ variable [LinearOrderedAddCommGroup α]
 https://leanprover.zulipchat.com/#narrow/stream/113488-general/topic/Decidable.20vs.20decidable_rel -/
 attribute [local instance] LinearOrderedAddCommGroup.decidableLt
 
+#print sign_sum /-
 theorem sign_sum {ι : Type _} {s : Finset ι} {f : ι → α} (hs : s.Nonempty) (t : SignType)
     (h : ∀ i ∈ s, SignType.sign (f i) = t) : SignType.sign (∑ i in s, f i) = t :=
   by
@@ -518,6 +549,7 @@ theorem sign_sum {ι : Type _} {s : Finset ι} {f : ι → α} (hs : s.Nonempty)
   · simp_rw [pos_eq_one, sign_eq_one_iff] at h ⊢
     exact Finset.sum_pos h hs
 #align sign_sum sign_sum
+-/
 
 end LinearOrderedAddCommGroup
 
@@ -553,6 +585,7 @@ private theorem exists_signed_sum_aux [DecidableEq α] (s : Finset α) (f : α 
     simp [sum_sigma, hx, ← Int.sign_eq_sign, Int.sign_mul_abs, mul_comm (|f _|),
       @sum_attach _ _ _ _ fun a => ∑ j in range (f a).natAbs, if a = x then (f a).sign else 0]
 
+#print exists_signed_sum /-
 /-- We can decompose a sum of absolute value `n` into a sum of `n` signs. -/
 theorem exists_signed_sum [DecidableEq α] (s : Finset α) (f : α → ℤ) :
     ∃ (β : Type u_1) (_ : Fintype β) (sgn : β → SignType) (g : β → α),
@@ -563,7 +596,9 @@ theorem exists_signed_sum [DecidableEq α] (s : Finset α) (f : α → ℤ) :
   ⟨t, inferInstance, fun b => sgn b, fun b => g b, fun b => hg b, by simp [ht], fun a ha =>
     (@sum_attach _ _ t _ fun b => ite (g b = a) (sgn b : ℤ) 0).trans <| hf _ ha⟩
 #align exists_signed_sum exists_signed_sum
+-/
 
+#print exists_signed_sum' /-
 /-- We can decompose a sum of absolute value less than `n` into a sum of at most `n` signs. -/
 theorem exists_signed_sum' [Nonempty α] [DecidableEq α] (s : Finset α) (f : α → ℤ) (n : ℕ)
     (h : ∑ i in s, (f i).natAbs ≤ n) :
@@ -580,4 +615,5 @@ theorem exists_signed_sum' [Nonempty α] [DecidableEq α] (s : Finset α) (f : 
   · cases hb (hg _)
   · rfl
 #align exists_signed_sum' exists_signed_sum'
+-/
 

mathlib commit https://github.com/leanprover-community/mathlib/commit/a3e83f0fa4391c8740f7d773a7a9b74e311ae2a3

@@ -542,7 +542,7 @@ open scoped BigOperators
 private theorem exists_signed_sum_aux [DecidableEq α] (s : Finset α) (f : α → ℤ) :
     ∃ (β : Type u_1) (t : Finset β) (sgn : β → SignType) (g : β → α),
       (∀ b, g b ∈ s) ∧
-        (t.card = ∑ a in s, (f a).natAbs) ∧
+        t.card = ∑ a in s, (f a).natAbs ∧
           ∀ a ∈ s, (∑ b in t, if g b = a then (sgn b : ℤ) else 0) = f a :=
   by
   refine'
@@ -557,7 +557,7 @@ private theorem exists_signed_sum_aux [DecidableEq α] (s : Finset α) (f : α 
 theorem exists_signed_sum [DecidableEq α] (s : Finset α) (f : α → ℤ) :
     ∃ (β : Type u_1) (_ : Fintype β) (sgn : β → SignType) (g : β → α),
       (∀ b, g b ∈ s) ∧
-        (Fintype.card β = ∑ a in s, (f a).natAbs) ∧
+        Fintype.card β = ∑ a in s, (f a).natAbs ∧
           ∀ a ∈ s, (∑ b, if g b = a then (sgn b : ℤ) else 0) = f a :=
   let ⟨β, t, sgn, g, hg, ht, hf⟩ := exists_signed_sum_aux s f
   ⟨t, inferInstance, fun b => sgn b, fun b => g b, fun b => hg b, by simp [ht], fun a ha =>
@@ -566,7 +566,7 @@ theorem exists_signed_sum [DecidableEq α] (s : Finset α) (f : α → ℤ) :
 
 /-- We can decompose a sum of absolute value less than `n` into a sum of at most `n` signs. -/
 theorem exists_signed_sum' [Nonempty α] [DecidableEq α] (s : Finset α) (f : α → ℤ) (n : ℕ)
-    (h : (∑ i in s, (f i).natAbs) ≤ n) :
+    (h : ∑ i in s, (f i).natAbs ≤ n) :
     ∃ (β : Type u_1) (_ : Fintype β) (sgn : β → SignType) (g : β → α),
       (∀ b, g b ∉ s → sgn b = 0) ∧
         Fintype.card β = n ∧ ∀ a ∈ s, (∑ i, if g i = a then (sgn i : ℤ) else 0) = f a :=

mathlib commit https://github.com/leanprover-community/mathlib/commit/5f25c089cb34db4db112556f23c50d12da81b297

@@ -305,7 +305,7 @@ def castHom {α} [MulZeroOneClass α] [HasDistribNeg α] : SignType →*₀ α
 #print SignType.range_eq /-
 theorem range_eq {α} (f : SignType → α) : Set.range f = {f zero, f neg, f pos} := by
   classical simpa only [← Finset.coe_singleton, ← Finset.image_singleton, ← Fintype.coe_image_univ,
-      Finset.coe_image, ← Set.image_insert_eq]
+    Finset.coe_image, ← Set.image_insert_eq]
 #align sign_type.range_eq SignType.range_eq
 -/
 
@@ -361,7 +361,7 @@ theorem sign_eq_one_iff : SignType.sign a = 1 ↔ 0 < a :=
   refine' ⟨fun h => _, fun h => sign_pos h⟩
   by_contra hn
   rw [sign_apply, if_neg hn] at h 
-  split_ifs  at h  <;> simpa using h
+  split_ifs at h  <;> simpa using h
 #align sign_eq_one_iff sign_eq_one_iff
 -/
 
@@ -370,7 +370,7 @@ theorem sign_eq_neg_one_iff : SignType.sign a = -1 ↔ a < 0 :=
   by
   refine' ⟨fun h => _, fun h => sign_neg h⟩
   rw [sign_apply] at h 
-  split_ifs  at h 
+  split_ifs at h 
   · simpa using h
   · exact h_2
   · simpa using h
@@ -389,7 +389,7 @@ theorem sign_eq_zero_iff : SignType.sign a = 0 ↔ a = 0 :=
   by
   refine' ⟨fun h => _, fun h => h.symm ▸ sign_zero⟩
   rw [sign_apply] at h 
-  split_ifs  at h  <;> cases h
+  split_ifs at h  <;> cases h
   exact (le_of_not_lt h_1).eq_of_not_lt h_2
 #align sign_eq_zero_iff sign_eq_zero_iff
 -/

mathlib commit https://github.com/leanprover-community/mathlib/commit/cca40788df1b8755d5baf17ab2f27dacc2e17acb

@@ -90,7 +90,10 @@ instance : LE SignType :=
   ⟨Le⟩
 
 instance : DecidableRel Le := fun a b => by
-  cases a <;> cases b <;> first |exact is_false (by rintro ⟨⟩)|exact is_true (by constructor)
+  cases a <;> cases b <;>
+    first
+    | exact is_false (by rintro ⟨⟩)
+    | exact is_true (by constructor)
 
 /- We can define a `field` instance on `sign_type`, but it's not mathematically sensible,
 so we only define the `comm_group_with_zero`. -/
@@ -357,8 +360,8 @@ theorem sign_eq_one_iff : SignType.sign a = 1 ↔ 0 < a :=
   by
   refine' ⟨fun h => _, fun h => sign_pos h⟩
   by_contra hn
-  rw [sign_apply, if_neg hn] at h
-  split_ifs  at h <;> simpa using h
+  rw [sign_apply, if_neg hn] at h 
+  split_ifs  at h  <;> simpa using h
 #align sign_eq_one_iff sign_eq_one_iff
 -/
 
@@ -366,8 +369,8 @@ theorem sign_eq_one_iff : SignType.sign a = 1 ↔ 0 < a :=
 theorem sign_eq_neg_one_iff : SignType.sign a = -1 ↔ a < 0 :=
   by
   refine' ⟨fun h => _, fun h => sign_neg h⟩
-  rw [sign_apply] at h
-  split_ifs  at h
+  rw [sign_apply] at h 
+  split_ifs  at h 
   · simpa using h
   · exact h_2
   · simpa using h
@@ -385,8 +388,8 @@ variable [Zero α] [LinearOrder α] {a : α}
 theorem sign_eq_zero_iff : SignType.sign a = 0 ↔ a = 0 :=
   by
   refine' ⟨fun h => _, fun h => h.symm ▸ sign_zero⟩
-  rw [sign_apply] at h
-  split_ifs  at h <;> cases h
+  rw [sign_apply] at h 
+  split_ifs  at h  <;> cases h
   exact (le_of_not_lt h_1).eq_of_not_lt h_2
 #align sign_eq_zero_iff sign_eq_zero_iff
 -/
@@ -508,11 +511,11 @@ theorem sign_sum {ι : Type _} {s : Finset ι} {f : ι → α} (hs : s.Nonempty)
     (h : ∀ i ∈ s, SignType.sign (f i) = t) : SignType.sign (∑ i in s, f i) = t :=
   by
   cases t
-  · simp_rw [zero_eq_zero, sign_eq_zero_iff] at h⊢
+  · simp_rw [zero_eq_zero, sign_eq_zero_iff] at h ⊢
     exact Finset.sum_eq_zero h
-  · simp_rw [neg_eq_neg_one, sign_eq_neg_one_iff] at h⊢
+  · simp_rw [neg_eq_neg_one, sign_eq_neg_one_iff] at h ⊢
     exact Finset.sum_neg h hs
-  · simp_rw [pos_eq_one, sign_eq_one_iff] at h⊢
+  · simp_rw [pos_eq_one, sign_eq_one_iff] at h ⊢
     exact Finset.sum_pos h hs
 #align sign_sum sign_sum
 
@@ -537,13 +540,13 @@ open Finset Nat
 open scoped BigOperators
 
 private theorem exists_signed_sum_aux [DecidableEq α] (s : Finset α) (f : α → ℤ) :
-    ∃ (β : Type u_1)(t : Finset β)(sgn : β → SignType)(g : β → α),
+    ∃ (β : Type u_1) (t : Finset β) (sgn : β → SignType) (g : β → α),
       (∀ b, g b ∈ s) ∧
         (t.card = ∑ a in s, (f a).natAbs) ∧
           ∀ a ∈ s, (∑ b in t, if g b = a then (sgn b : ℤ) else 0) = f a :=
   by
   refine'
-    ⟨Σa : { x // x ∈ s }, ℕ, finset.univ.sigma fun a => range (f a).natAbs, fun a =>
+    ⟨Σ a : { x // x ∈ s }, ℕ, finset.univ.sigma fun a => range (f a).natAbs, fun a =>
       SignType.sign (f a.1), fun a => a.1, fun a => a.1.Prop, _, _⟩
   · simp [@sum_attach _ _ _ _ fun a => (f a).natAbs]
   · intro x hx
@@ -552,7 +555,7 @@ private theorem exists_signed_sum_aux [DecidableEq α] (s : Finset α) (f : α 
 
 /-- We can decompose a sum of absolute value `n` into a sum of `n` signs. -/
 theorem exists_signed_sum [DecidableEq α] (s : Finset α) (f : α → ℤ) :
-    ∃ (β : Type u_1)(_ : Fintype β)(sgn : β → SignType)(g : β → α),
+    ∃ (β : Type u_1) (_ : Fintype β) (sgn : β → SignType) (g : β → α),
       (∀ b, g b ∈ s) ∧
         (Fintype.card β = ∑ a in s, (f a).natAbs) ∧
           ∀ a ∈ s, (∑ b, if g b = a then (sgn b : ℤ) else 0) = f a :=
@@ -564,7 +567,7 @@ theorem exists_signed_sum [DecidableEq α] (s : Finset α) (f : α → ℤ) :
 /-- We can decompose a sum of absolute value less than `n` into a sum of at most `n` signs. -/
 theorem exists_signed_sum' [Nonempty α] [DecidableEq α] (s : Finset α) (f : α → ℤ) (n : ℕ)
     (h : (∑ i in s, (f i).natAbs) ≤ n) :
-    ∃ (β : Type u_1)(_ : Fintype β)(sgn : β → SignType)(g : β → α),
+    ∃ (β : Type u_1) (_ : Fintype β) (sgn : β → SignType) (g : β → α),
       (∀ b, g b ∉ s → sgn b = 0) ∧
         Fintype.card β = n ∧ ∀ a ∈ s, (∑ i, if g i = a then (sgn i : ℤ) else 0) = f a :=
   by

mathlib commit https://github.com/leanprover-community/mathlib/commit/917c3c072e487b3cccdbfeff17e75b40e45f66cb

@@ -327,23 +327,32 @@ def SignType.sign : α →o SignType :=
     · cases h₄ (h.trans_lt h₃)⟩
 #align sign SignType.sign
 
+#print sign_apply /-
 theorem sign_apply : SignType.sign a = ite (0 < a) 1 (ite (a < 0) (-1) 0) :=
   rfl
 #align sign_apply sign_apply
+-/
 
+#print sign_zero /-
 @[simp]
 theorem sign_zero : SignType.sign (0 : α) = 0 := by simp [sign_apply]
 #align sign_zero sign_zero
+-/
 
+#print sign_pos /-
 @[simp]
 theorem sign_pos (ha : 0 < a) : SignType.sign a = 1 := by rwa [sign_apply, if_pos]
 #align sign_pos sign_pos
+-/
 
+#print sign_neg /-
 @[simp]
 theorem sign_neg (ha : a < 0) : SignType.sign a = -1 := by
   rwa [sign_apply, if_neg <| asymm ha, if_pos]
 #align sign_neg sign_neg
+-/
 
+#print sign_eq_one_iff /-
 theorem sign_eq_one_iff : SignType.sign a = 1 ↔ 0 < a :=
   by
   refine' ⟨fun h => _, fun h => sign_pos h⟩
@@ -351,7 +360,9 @@ theorem sign_eq_one_iff : SignType.sign a = 1 ↔ 0 < a :=
   rw [sign_apply, if_neg hn] at h
   split_ifs  at h <;> simpa using h
 #align sign_eq_one_iff sign_eq_one_iff
+-/
 
+#print sign_eq_neg_one_iff /-
 theorem sign_eq_neg_one_iff : SignType.sign a = -1 ↔ a < 0 :=
   by
   refine' ⟨fun h => _, fun h => sign_neg h⟩
@@ -361,6 +372,7 @@ theorem sign_eq_neg_one_iff : SignType.sign a = -1 ↔ a < 0 :=
   · exact h_2
   · simpa using h
 #align sign_eq_neg_one_iff sign_eq_neg_one_iff
+-/
 
 end Preorder
 
@@ -484,7 +496,7 @@ end AddGroup
 
 section LinearOrderedAddCommGroup
 
-open BigOperators
+open scoped BigOperators
 
 variable [LinearOrderedAddCommGroup α]
 
@@ -522,7 +534,7 @@ end Int
 
 open Finset Nat
 
-open BigOperators
+open scoped BigOperators
 
 private theorem exists_signed_sum_aux [DecidableEq α] (s : Finset α) (f : α → ℤ) :
     ∃ (β : Type u_1)(t : Finset β)(sgn : β → SignType)(g : β → α),

mathlib commit https://github.com/leanprover-community/mathlib/commit/917c3c072e487b3cccdbfeff17e75b40e45f66cb

@@ -163,12 +163,6 @@ theorem nonneg_iff_ne_neg_one {a : SignType} : 0 ≤ a ↔ a ≠ -1 := by decide
 #align sign_type.nonneg_iff_ne_neg_one SignType.nonneg_iff_ne_neg_one
 -/
 
-/- warning: sign_type.neg_one_lt_iff -> SignType.neg_one_lt_iff is a dubious translation:
-lean 3 declaration is
-  forall {a : SignType}, Iff (LT.lt.{0} SignType (Preorder.toHasLt.{0} SignType (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) (Neg.neg.{0} SignType SignType.hasNeg (OfNat.ofNat.{0} SignType 1 (OfNat.mk.{0} SignType 1 (One.one.{0} SignType SignType.hasOne)))) a) (LE.le.{0} SignType SignType.hasLe (OfNat.ofNat.{0} SignType 0 (OfNat.mk.{0} SignType 0 (Zero.zero.{0} SignType SignType.hasZero))) a)
-but is expected to have type
-  forall {a : SignType}, Iff (LT.lt.{0} SignType (Preorder.toLT.{0} SignType (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (DistribLattice.toLattice.{0} SignType (instDistribLattice.{0} SignType SignType.instLinearOrderSignType)))))) (Neg.neg.{0} SignType SignType.instNegSignType (OfNat.ofNat.{0} SignType 1 (One.toOfNat1.{0} SignType SignType.instOneSignType))) a) (LE.le.{0} SignType SignType.instLESignType (OfNat.ofNat.{0} SignType 0 (Zero.toOfNat0.{0} SignType SignType.instZeroSignType)) a)
-Case conversion may be inaccurate. Consider using '#align sign_type.neg_one_lt_iff SignType.neg_one_lt_iffₓ'. -/
 theorem neg_one_lt_iff {a : SignType} : -1 < a ↔ 0 ≤ a := by decide!
 #align sign_type.neg_one_lt_iff SignType.neg_one_lt_iff
 
@@ -182,21 +176,9 @@ theorem nonpos_iff_ne_one {a : SignType} : a ≤ 0 ↔ a ≠ 1 := by decide!
 #align sign_type.nonpos_iff_ne_one SignType.nonpos_iff_ne_one
 -/
 
-/- warning: sign_type.lt_one_iff -> SignType.lt_one_iff is a dubious translation:
-lean 3 declaration is
-  forall {a : SignType}, Iff (LT.lt.{0} SignType (Preorder.toHasLt.{0} SignType (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) a (OfNat.ofNat.{0} SignType 1 (OfNat.mk.{0} SignType 1 (One.one.{0} SignType SignType.hasOne)))) (LE.le.{0} SignType SignType.hasLe a (OfNat.ofNat.{0} SignType 0 (OfNat.mk.{0} SignType 0 (Zero.zero.{0} SignType SignType.hasZero))))
-but is expected to have type
-  forall {a : SignType}, Iff (LT.lt.{0} SignType (Preorder.toLT.{0} SignType (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (DistribLattice.toLattice.{0} SignType (instDistribLattice.{0} SignType SignType.instLinearOrderSignType)))))) a (OfNat.ofNat.{0} SignType 1 (One.toOfNat1.{0} SignType SignType.instOneSignType))) (LE.le.{0} SignType SignType.instLESignType a (OfNat.ofNat.{0} SignType 0 (Zero.toOfNat0.{0} SignType SignType.instZeroSignType)))
-Case conversion may be inaccurate. Consider using '#align sign_type.lt_one_iff SignType.lt_one_iffₓ'. -/
 theorem lt_one_iff {a : SignType} : a < 1 ↔ a ≤ 0 := by decide!
 #align sign_type.lt_one_iff SignType.lt_one_iff
 
-/- warning: sign_type.neg_iff -> SignType.neg_iff is a dubious translation:
-lean 3 declaration is
-  forall {a : SignType}, Iff (LT.lt.{0} SignType (Preorder.toHasLt.{0} SignType (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) a (OfNat.ofNat.{0} SignType 0 (OfNat.mk.{0} SignType 0 (Zero.zero.{0} SignType SignType.hasZero)))) (Eq.{1} SignType a (Neg.neg.{0} SignType SignType.hasNeg (OfNat.ofNat.{0} SignType 1 (OfNat.mk.{0} SignType 1 (One.one.{0} SignType SignType.hasOne)))))
-but is expected to have type
-  forall {a : SignType}, Iff (LT.lt.{0} SignType (Preorder.toLT.{0} SignType (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (DistribLattice.toLattice.{0} SignType (instDistribLattice.{0} SignType SignType.instLinearOrderSignType)))))) a (OfNat.ofNat.{0} SignType 0 (Zero.toOfNat0.{0} SignType SignType.instZeroSignType))) (Eq.{1} SignType a (Neg.neg.{0} SignType SignType.instNegSignType (OfNat.ofNat.{0} SignType 1 (One.toOfNat1.{0} SignType SignType.instOneSignType))))
-Case conversion may be inaccurate. Consider using '#align sign_type.neg_iff SignType.neg_iffₓ'. -/
 @[simp]
 theorem neg_iff {a : SignType} : a < 0 ↔ a = -1 := by decide!
 #align sign_type.neg_iff SignType.neg_iff
@@ -208,12 +190,6 @@ theorem le_neg_one_iff {a : SignType} : a ≤ -1 ↔ a = -1 :=
 #align sign_type.le_neg_one_iff SignType.le_neg_one_iff
 -/
 
-/- warning: sign_type.pos_iff -> SignType.pos_iff is a dubious translation:
-lean 3 declaration is
-  forall {a : SignType}, Iff (LT.lt.{0} SignType (Preorder.toHasLt.{0} SignType (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) (OfNat.ofNat.{0} SignType 0 (OfNat.mk.{0} SignType 0 (Zero.zero.{0} SignType SignType.hasZero))) a) (Eq.{1} SignType a (OfNat.ofNat.{0} SignType 1 (OfNat.mk.{0} SignType 1 (One.one.{0} SignType SignType.hasOne))))
-but is expected to have type
-  forall {a : SignType}, Iff (LT.lt.{0} SignType (Preorder.toLT.{0} SignType (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (DistribLattice.toLattice.{0} SignType (instDistribLattice.{0} SignType SignType.instLinearOrderSignType)))))) (OfNat.ofNat.{0} SignType 0 (Zero.toOfNat0.{0} SignType SignType.instZeroSignType)) a) (Eq.{1} SignType a (OfNat.ofNat.{0} SignType 1 (One.toOfNat1.{0} SignType SignType.instOneSignType)))
-Case conversion may be inaccurate. Consider using '#align sign_type.pos_iff SignType.pos_iffₓ'. -/
 @[simp]
 theorem pos_iff {a : SignType} : 0 < a ↔ a = 1 := by decide!
 #align sign_type.pos_iff SignType.pos_iff
@@ -239,23 +215,11 @@ theorem le_one (a : SignType) : a ≤ 1 :=
 #align sign_type.le_one SignType.le_one
 -/
 
-/- warning: sign_type.not_lt_neg_one -> SignType.not_lt_neg_one is a dubious translation:
-lean 3 declaration is
-  forall (a : SignType), Not (LT.lt.{0} SignType (Preorder.toHasLt.{0} SignType (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) a (Neg.neg.{0} SignType SignType.hasNeg (OfNat.ofNat.{0} SignType 1 (OfNat.mk.{0} SignType 1 (One.one.{0} SignType SignType.hasOne)))))
-but is expected to have type
-  forall (a : SignType), Not (LT.lt.{0} SignType (Preorder.toLT.{0} SignType (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (DistribLattice.toLattice.{0} SignType (instDistribLattice.{0} SignType SignType.instLinearOrderSignType)))))) a (Neg.neg.{0} SignType SignType.instNegSignType (OfNat.ofNat.{0} SignType 1 (One.toOfNat1.{0} SignType SignType.instOneSignType))))
-Case conversion may be inaccurate. Consider using '#align sign_type.not_lt_neg_one SignType.not_lt_neg_oneₓ'. -/
 @[simp]
 theorem not_lt_neg_one (a : SignType) : ¬a < -1 :=
   not_lt_bot
 #align sign_type.not_lt_neg_one SignType.not_lt_neg_one
 
-/- warning: sign_type.not_one_lt -> SignType.not_one_lt is a dubious translation:
-lean 3 declaration is
-  forall (a : SignType), Not (LT.lt.{0} SignType (Preorder.toHasLt.{0} SignType (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) (OfNat.ofNat.{0} SignType 1 (OfNat.mk.{0} SignType 1 (One.one.{0} SignType SignType.hasOne))) a)
-but is expected to have type
-  forall (a : SignType), Not (LT.lt.{0} SignType (Preorder.toLT.{0} SignType (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (DistribLattice.toLattice.{0} SignType (instDistribLattice.{0} SignType SignType.instLinearOrderSignType)))))) (OfNat.ofNat.{0} SignType 1 (One.toOfNat1.{0} SignType SignType.instOneSignType)) a)
-Case conversion may be inaccurate. Consider using '#align sign_type.not_one_lt SignType.not_one_ltₓ'. -/
 @[simp]
 theorem not_one_lt (a : SignType) : ¬1 < a :=
   not_top_lt
@@ -273,12 +237,6 @@ theorem neg_eq_self_iff (a : SignType) : -a = a ↔ a = 0 := by decide!
 #align sign_type.neg_eq_self_iff SignType.neg_eq_self_iff
 -/
 
-/- warning: sign_type.neg_one_lt_one -> SignType.neg_one_lt_one is a dubious translation:
-lean 3 declaration is
-  LT.lt.{0} SignType (Preorder.toHasLt.{0} SignType (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) (Neg.neg.{0} SignType SignType.hasNeg (OfNat.ofNat.{0} SignType 1 (OfNat.mk.{0} SignType 1 (One.one.{0} SignType SignType.hasOne)))) (OfNat.ofNat.{0} SignType 1 (OfNat.mk.{0} SignType 1 (One.one.{0} SignType SignType.hasOne)))
-but is expected to have type
-  LT.lt.{0} SignType (Preorder.toLT.{0} SignType (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (DistribLattice.toLattice.{0} SignType (instDistribLattice.{0} SignType SignType.instLinearOrderSignType)))))) (Neg.neg.{0} SignType SignType.instNegSignType (OfNat.ofNat.{0} SignType 1 (One.toOfNat1.{0} SignType SignType.instOneSignType))) (OfNat.ofNat.{0} SignType 1 (One.toOfNat1.{0} SignType SignType.instOneSignType))
-Case conversion may be inaccurate. Consider using '#align sign_type.neg_one_lt_one SignType.neg_one_lt_oneₓ'. -/
 @[simp]
 theorem neg_one_lt_one : (-1 : SignType) < 1 :=
   bot_lt_top
@@ -331,12 +289,6 @@ theorem coe_neg_one : ↑(-1 : SignType) = (-1 : α) :=
 
 end cast
 
-/- warning: sign_type.cast_hom -> SignType.castHom is a dubious translation:
-lean 3 declaration is
-  forall {α : Type.{u1}} [_inst_1 : MulZeroOneClass.{u1} α] [_inst_2 : HasDistribNeg.{u1} α (MulZeroClass.toHasMul.{u1} α (MulZeroOneClass.toMulZeroClass.{u1} α _inst_1))], MonoidWithZeroHom.{0, u1} SignType α (MonoidWithZero.toMulZeroOneClass.{0} SignType (GroupWithZero.toMonoidWithZero.{0} SignType (CommGroupWithZero.toGroupWithZero.{0} SignType SignType.commGroupWithZero))) _inst_1
-but is expected to have type
-  forall {α : Type.{u1}} [_inst_1 : MulZeroOneClass.{u1} α] [_inst_2 : HasDistribNeg.{u1} α (MulZeroClass.toMul.{u1} α (MulZeroOneClass.toMulZeroClass.{u1} α _inst_1))], MonoidWithZeroHom.{0, u1} SignType α (MonoidWithZero.toMulZeroOneClass.{0} SignType (GroupWithZero.toMonoidWithZero.{0} SignType (CommGroupWithZero.toGroupWithZero.{0} SignType SignType.instCommGroupWithZeroSignType))) _inst_1
-Case conversion may be inaccurate. Consider using '#align sign_type.cast_hom SignType.castHomₓ'. -/
 /-- `sign_type.cast` as a `mul_with_zero_hom`. -/
 @[simps]
 def castHom {α} [MulZeroOneClass α] [HasDistribNeg α] : SignType →*₀ α
@@ -364,12 +316,6 @@ section Preorder
 
 variable [Zero α] [Preorder α] [DecidableRel ((· < ·) : α → α → Prop)] {a : α}
 
-/- warning: sign -> SignType.sign is a dubious translation:
-lean 3 declaration is
-  forall {α : Type.{u1}} [_inst_1 : Zero.{u1} α] [_inst_2 : Preorder.{u1} α] [_inst_3 : DecidableRel.{succ u1} α (LT.lt.{u1} α (Preorder.toHasLt.{u1} α _inst_2))], OrderHom.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))
-but is expected to have type
-  forall {α : Type.{u1}} [_inst_1 : Zero.{u1} α] [_inst_2 : Preorder.{u1} α] [_inst_3 : DecidableRel.{succ u1} α (fun (x._@.Mathlib.Data.Sign._hyg.4988 : α) (x._@.Mathlib.Data.Sign._hyg.4990 : α) => LT.lt.{u1} α (Preorder.toLT.{u1} α _inst_2) x._@.Mathlib.Data.Sign._hyg.4988 x._@.Mathlib.Data.Sign._hyg.4990)], OrderHom.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (DistribLattice.toLattice.{0} SignType (instDistribLattice.{0} SignType SignType.instLinearOrderSignType)))))
-Case conversion may be inaccurate. Consider using '#align sign SignType.signₓ'. -/
 /-- The sign of an element is 1 if it's positive, -1 if negative, 0 otherwise. -/
 def SignType.sign : α →o SignType :=
   ⟨fun a => if 0 < a then 1 else if a < 0 then -1 else 0, fun a b h =>
@@ -381,53 +327,23 @@ def SignType.sign : α →o SignType :=
     · cases h₄ (h.trans_lt h₃)⟩
 #align sign SignType.sign
 
-/- warning: sign_apply -> sign_apply is a dubious translation:
-lean 3 declaration is
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-Case conversion may be inaccurate. Consider using '#align sign_apply sign_applyₓ'. -/
 theorem sign_apply : SignType.sign a = ite (0 < a) 1 (ite (a < 0) (-1) 0) :=
   rfl
 #align sign_apply sign_apply
 
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 @[simp]
 theorem sign_zero : SignType.sign (0 : α) = 0 := by simp [sign_apply]
 #align sign_zero sign_zero
 
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-Case conversion may be inaccurate. Consider using '#align sign_pos sign_posₓ'. -/
 @[simp]
 theorem sign_pos (ha : 0 < a) : SignType.sign a = 1 := by rwa [sign_apply, if_pos]
 #align sign_pos sign_pos
 
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-Case conversion may be inaccurate. Consider using '#align sign_neg sign_negₓ'. -/
 @[simp]
 theorem sign_neg (ha : a < 0) : SignType.sign a = -1 := by
   rwa [sign_apply, if_neg <| asymm ha, if_pos]
 #align sign_neg sign_neg
 
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 theorem sign_eq_one_iff : SignType.sign a = 1 ↔ 0 < a :=
   by
   refine' ⟨fun h => _, fun h => sign_pos h⟩
@@ -436,12 +352,6 @@ theorem sign_eq_one_iff : SignType.sign a = 1 ↔ 0 < a :=
   split_ifs  at h <;> simpa using h
 #align sign_eq_one_iff sign_eq_one_iff
 
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 theorem sign_eq_neg_one_iff : SignType.sign a = -1 ↔ a < 0 :=
   by
   refine' ⟨fun h => _, fun h => sign_neg h⟩
@@ -503,12 +413,6 @@ section OrderedSemiring
 
 variable [OrderedSemiring α] [DecidableRel ((· < ·) : α → α → Prop)] [Nontrivial α]
 
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-Case conversion may be inaccurate. Consider using '#align sign_one sign_oneₓ'. -/
 @[simp]
 theorem sign_one : SignType.sign (1 : α) = 1 :=
   sign_pos zero_lt_one
@@ -524,12 +428,6 @@ variable [LinearOrderedRing α] {a b : α}
 113488-general/topic/type.20class.20inference.20issues/near/276937942 -/
 attribute [local instance] LinearOrderedRing.decidableLt
 
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-Case conversion may be inaccurate. Consider using '#align sign_mul sign_mulₓ'. -/
 theorem sign_mul (x y : α) : SignType.sign (x * y) = SignType.sign x * SignType.sign y := by
   rcases lt_trichotomy x 0 with (hx | hx | hx) <;> rcases lt_trichotomy y 0 with (hy | hy | hy) <;>
     simp only [sign_zero, MulZeroClass.mul_zero, MulZeroClass.zero_mul, sign_pos, sign_neg, hx, hy,
@@ -537,12 +435,6 @@ theorem sign_mul (x y : α) : SignType.sign (x * y) = SignType.sign x * SignType
       neg_zero, mul_neg_of_pos_of_neg, mul_pos]
 #align sign_mul sign_mul
 
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-Case conversion may be inaccurate. Consider using '#align sign_hom signHomₓ'. -/
 /-- `sign` as a `monoid_with_zero_hom` for a nontrivial ordered semiring. Note that linearity
 is required; consider ℂ with the order `z ≤ w` iff they have the same imaginary part and
 `z - w ≤ 0` in the reals; then `1 + i` and `1 - i` are incomparable to zero, and thus we have:
@@ -554,12 +446,6 @@ def signHom : α →*₀ SignType where
   map_mul' := sign_mul
 #align sign_hom signHom
 
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-Case conversion may be inaccurate. Consider using '#align sign_pow sign_powₓ'. -/
 theorem sign_pow (x : α) (n : ℕ) : SignType.sign (x ^ n) = SignType.sign x ^ n :=
   by
   change signHom (x ^ n) = signHom x ^ n
@@ -572,12 +458,6 @@ section AddGroup
 
 variable [AddGroup α] [Preorder α] [DecidableRel ((· < ·) : α → α → Prop)]
 
-/- warning: left.sign_neg -> Left.sign_neg is a dubious translation:
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-Case conversion may be inaccurate. Consider using '#align left.sign_neg Left.sign_negₓ'. -/
 theorem Left.sign_neg [CovariantClass α α (· + ·) (· < ·)] (a : α) :
     SignType.sign (-a) = -SignType.sign a :=
   by
@@ -589,12 +469,6 @@ theorem Left.sign_neg [CovariantClass α α (· + ·) (· < ·)] (a : α) :
   · simp
 #align left.sign_neg Left.sign_neg
 
-/- warning: right.sign_neg -> Right.sign_neg is a dubious translation:
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-but is expected to have type
-  forall {α : Type.{u1}} [_inst_1 : AddGroup.{u1} α] [_inst_2 : Preorder.{u1} α] [_inst_3 : DecidableRel.{succ u1} α (fun (x._@.Mathlib.Data.Sign._hyg.6586 : α) (x._@.Mathlib.Data.Sign._hyg.6588 : α) => LT.lt.{u1} α (Preorder.toLT.{u1} α _inst_2) x._@.Mathlib.Data.Sign._hyg.6586 x._@.Mathlib.Data.Sign._hyg.6588)] [_inst_4 : CovariantClass.{u1, u1} α α (Function.swap.{succ u1, succ u1, succ u1} α α (fun (ᾰ : α) (ᾰ : α) => α) (fun (x._@.Mathlib.Data.Sign._hyg.6608 : α) (x._@.Mathlib.Data.Sign._hyg.6610 : α) => HAdd.hAdd.{u1, u1, u1} α α α (instHAdd.{u1} α (AddZeroClass.toAdd.{u1} α (AddMonoid.toAddZeroClass.{u1} α (SubNegMonoid.toAddMonoid.{u1} α (AddGroup.toSubNegMonoid.{u1} α _inst_1))))) x._@.Mathlib.Data.Sign._hyg.6608 x._@.Mathlib.Data.Sign._hyg.6610)) (fun (x._@.Mathlib.Data.Sign._hyg.6623 : α) (x._@.Mathlib.Data.Sign._hyg.6625 : α) => LT.lt.{u1} α (Preorder.toLT.{u1} α _inst_2) x._@.Mathlib.Data.Sign._hyg.6623 x._@.Mathlib.Data.Sign._hyg.6625)] (a : α), Eq.{1} SignType (OrderHom.toFun.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (DistribLattice.toLattice.{0} SignType (instDistribLattice.{0} SignType SignType.instLinearOrderSignType))))) (SignType.sign.{u1} α (NegZeroClass.toZero.{u1} α (SubNegZeroMonoid.toNegZeroClass.{u1} α (SubtractionMonoid.toSubNegZeroMonoid.{u1} α (AddGroup.toSubtractionMonoid.{u1} α _inst_1)))) _inst_2 (fun (a : α) (b : α) => _inst_3 a b)) (Neg.neg.{u1} α (NegZeroClass.toNeg.{u1} α (SubNegZeroMonoid.toNegZeroClass.{u1} α (SubtractionMonoid.toSubNegZeroMonoid.{u1} α (AddGroup.toSubtractionMonoid.{u1} α _inst_1)))) a)) (Neg.neg.{0} SignType SignType.instNegSignType (OrderHom.toFun.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (DistribLattice.toLattice.{0} SignType (instDistribLattice.{0} SignType SignType.instLinearOrderSignType))))) (SignType.sign.{u1} α (NegZeroClass.toZero.{u1} α (SubNegZeroMonoid.toNegZeroClass.{u1} α (SubtractionMonoid.toSubNegZeroMonoid.{u1} α (AddGroup.toSubtractionMonoid.{u1} α _inst_1)))) _inst_2 (fun (a : α) (b : α) => _inst_3 a b)) a))
-Case conversion may be inaccurate. Consider using '#align right.sign_neg Right.sign_negₓ'. -/
 theorem Right.sign_neg [CovariantClass α α (Function.swap (· + ·)) (· < ·)] (a : α) :
     SignType.sign (-a) = -SignType.sign a :=
   by
@@ -618,12 +492,6 @@ variable [LinearOrderedAddCommGroup α]
 https://leanprover.zulipchat.com/#narrow/stream/113488-general/topic/Decidable.20vs.20decidable_rel -/
 attribute [local instance] LinearOrderedAddCommGroup.decidableLt
 
-/- warning: sign_sum -> sign_sum is a dubious translation:
-lean 3 declaration is
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-Case conversion may be inaccurate. Consider using '#align sign_sum sign_sumₓ'. -/
 theorem sign_sum {ι : Type _} {s : Finset ι} {f : ι → α} (hs : s.Nonempty) (t : SignType)
     (h : ∀ i ∈ s, SignType.sign (f i) = t) : SignType.sign (∑ i in s, f i) = t :=
   by
@@ -670,9 +538,6 @@ private theorem exists_signed_sum_aux [DecidableEq α] (s : Finset α) (f : α 
     simp [sum_sigma, hx, ← Int.sign_eq_sign, Int.sign_mul_abs, mul_comm (|f _|),
       @sum_attach _ _ _ _ fun a => ∑ j in range (f a).natAbs, if a = x then (f a).sign else 0]
 
-/- warning: exists_signed_sum -> exists_signed_sum is a dubious translation:
-<too large>
-Case conversion may be inaccurate. Consider using '#align exists_signed_sum exists_signed_sumₓ'. -/
 /-- We can decompose a sum of absolute value `n` into a sum of `n` signs. -/
 theorem exists_signed_sum [DecidableEq α] (s : Finset α) (f : α → ℤ) :
     ∃ (β : Type u_1)(_ : Fintype β)(sgn : β → SignType)(g : β → α),
@@ -684,9 +549,6 @@ theorem exists_signed_sum [DecidableEq α] (s : Finset α) (f : α → ℤ) :
     (@sum_attach _ _ t _ fun b => ite (g b = a) (sgn b : ℤ) 0).trans <| hf _ ha⟩
 #align exists_signed_sum exists_signed_sum
 
-/- warning: exists_signed_sum' -> exists_signed_sum' is a dubious translation:
-<too large>
-Case conversion may be inaccurate. Consider using '#align exists_signed_sum' exists_signed_sum'ₓ'. -/
 /-- We can decompose a sum of absolute value less than `n` into a sum of at most `n` signs. -/
 theorem exists_signed_sum' [Nonempty α] [DecidableEq α] (s : Finset α) (f : α → ℤ) (n : ℕ)
     (h : (∑ i in s, (f i).natAbs) ≤ n) :

mathlib commit https://github.com/leanprover-community/mathlib/commit/917c3c072e487b3cccdbfeff17e75b40e45f66cb

@@ -669,13 +669,9 @@ private theorem exists_signed_sum_aux [DecidableEq α] (s : Finset α) (f : α 
   · intro x hx
     simp [sum_sigma, hx, ← Int.sign_eq_sign, Int.sign_mul_abs, mul_comm (|f _|),
       @sum_attach _ _ _ _ fun a => ∑ j in range (f a).natAbs, if a = x then (f a).sign else 0]
-#align exists_signed_sum_aux exists_signed_sum_aux
 
 /- warning: exists_signed_sum -> exists_signed_sum is a dubious translation:
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+<too large>
 Case conversion may be inaccurate. Consider using '#align exists_signed_sum exists_signed_sumₓ'. -/
 /-- We can decompose a sum of absolute value `n` into a sum of `n` signs. -/
 theorem exists_signed_sum [DecidableEq α] (s : Finset α) (f : α → ℤ) :
@@ -689,10 +685,7 @@ theorem exists_signed_sum [DecidableEq α] (s : Finset α) (f : α → ℤ) :
 #align exists_signed_sum exists_signed_sum
 
 /- warning: exists_signed_sum' -> exists_signed_sum' is a dubious translation:
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+<too large>
 Case conversion may be inaccurate. Consider using '#align exists_signed_sum' exists_signed_sum'ₓ'. -/
 /-- We can decompose a sum of absolute value less than `n` into a sum of at most `n` signs. -/
 theorem exists_signed_sum' [Nonempty α] [DecidableEq α] (s : Finset α) (f : α → ℤ) (n : ℕ)

mathlib commit https://github.com/leanprover-community/mathlib/commit/0b9eaaa7686280fad8cce467f5c3c57ee6ce77f8

@@ -165,7 +165,7 @@ theorem nonneg_iff_ne_neg_one {a : SignType} : 0 ≤ a ↔ a ≠ -1 := by decide
 
 /- warning: sign_type.neg_one_lt_iff -> SignType.neg_one_lt_iff is a dubious translation:
 lean 3 declaration is
-  forall {a : SignType}, Iff (LT.lt.{0} SignType (Preorder.toLT.{0} SignType (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) (Neg.neg.{0} SignType SignType.hasNeg (OfNat.ofNat.{0} SignType 1 (OfNat.mk.{0} SignType 1 (One.one.{0} SignType SignType.hasOne)))) a) (LE.le.{0} SignType SignType.hasLe (OfNat.ofNat.{0} SignType 0 (OfNat.mk.{0} SignType 0 (Zero.zero.{0} SignType SignType.hasZero))) a)
+  forall {a : SignType}, Iff (LT.lt.{0} SignType (Preorder.toHasLt.{0} SignType (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) (Neg.neg.{0} SignType SignType.hasNeg (OfNat.ofNat.{0} SignType 1 (OfNat.mk.{0} SignType 1 (One.one.{0} SignType SignType.hasOne)))) a) (LE.le.{0} SignType SignType.hasLe (OfNat.ofNat.{0} SignType 0 (OfNat.mk.{0} SignType 0 (Zero.zero.{0} SignType SignType.hasZero))) a)
 but is expected to have type
   forall {a : SignType}, Iff (LT.lt.{0} SignType (Preorder.toLT.{0} SignType (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (DistribLattice.toLattice.{0} SignType (instDistribLattice.{0} SignType SignType.instLinearOrderSignType)))))) (Neg.neg.{0} SignType SignType.instNegSignType (OfNat.ofNat.{0} SignType 1 (One.toOfNat1.{0} SignType SignType.instOneSignType))) a) (LE.le.{0} SignType SignType.instLESignType (OfNat.ofNat.{0} SignType 0 (Zero.toOfNat0.{0} SignType SignType.instZeroSignType)) a)
 Case conversion may be inaccurate. Consider using '#align sign_type.neg_one_lt_iff SignType.neg_one_lt_iffₓ'. -/
@@ -184,7 +184,7 @@ theorem nonpos_iff_ne_one {a : SignType} : a ≤ 0 ↔ a ≠ 1 := by decide!
 
 /- warning: sign_type.lt_one_iff -> SignType.lt_one_iff is a dubious translation:
 lean 3 declaration is
-  forall {a : SignType}, Iff (LT.lt.{0} SignType (Preorder.toLT.{0} SignType (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) a (OfNat.ofNat.{0} SignType 1 (OfNat.mk.{0} SignType 1 (One.one.{0} SignType SignType.hasOne)))) (LE.le.{0} SignType SignType.hasLe a (OfNat.ofNat.{0} SignType 0 (OfNat.mk.{0} SignType 0 (Zero.zero.{0} SignType SignType.hasZero))))
+  forall {a : SignType}, Iff (LT.lt.{0} SignType (Preorder.toHasLt.{0} SignType (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) a (OfNat.ofNat.{0} SignType 1 (OfNat.mk.{0} SignType 1 (One.one.{0} SignType SignType.hasOne)))) (LE.le.{0} SignType SignType.hasLe a (OfNat.ofNat.{0} SignType 0 (OfNat.mk.{0} SignType 0 (Zero.zero.{0} SignType SignType.hasZero))))
 but is expected to have type
   forall {a : SignType}, Iff (LT.lt.{0} SignType (Preorder.toLT.{0} SignType (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (DistribLattice.toLattice.{0} SignType (instDistribLattice.{0} SignType SignType.instLinearOrderSignType)))))) a (OfNat.ofNat.{0} SignType 1 (One.toOfNat1.{0} SignType SignType.instOneSignType))) (LE.le.{0} SignType SignType.instLESignType a (OfNat.ofNat.{0} SignType 0 (Zero.toOfNat0.{0} SignType SignType.instZeroSignType)))
 Case conversion may be inaccurate. Consider using '#align sign_type.lt_one_iff SignType.lt_one_iffₓ'. -/
@@ -193,7 +193,7 @@ theorem lt_one_iff {a : SignType} : a < 1 ↔ a ≤ 0 := by decide!
 
 /- warning: sign_type.neg_iff -> SignType.neg_iff is a dubious translation:
 lean 3 declaration is
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+  forall {a : SignType}, Iff (LT.lt.{0} SignType (Preorder.toHasLt.{0} SignType (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) a (OfNat.ofNat.{0} SignType 0 (OfNat.mk.{0} SignType 0 (Zero.zero.{0} SignType SignType.hasZero)))) (Eq.{1} SignType a (Neg.neg.{0} SignType SignType.hasNeg (OfNat.ofNat.{0} SignType 1 (OfNat.mk.{0} SignType 1 (One.one.{0} SignType SignType.hasOne)))))
 but is expected to have type
   forall {a : SignType}, Iff (LT.lt.{0} SignType (Preorder.toLT.{0} SignType (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (DistribLattice.toLattice.{0} SignType (instDistribLattice.{0} SignType SignType.instLinearOrderSignType)))))) a (OfNat.ofNat.{0} SignType 0 (Zero.toOfNat0.{0} SignType SignType.instZeroSignType))) (Eq.{1} SignType a (Neg.neg.{0} SignType SignType.instNegSignType (OfNat.ofNat.{0} SignType 1 (One.toOfNat1.{0} SignType SignType.instOneSignType))))
 Case conversion may be inaccurate. Consider using '#align sign_type.neg_iff SignType.neg_iffₓ'. -/
@@ -210,7 +210,7 @@ theorem le_neg_one_iff {a : SignType} : a ≤ -1 ↔ a = -1 :=
 
 /- warning: sign_type.pos_iff -> SignType.pos_iff is a dubious translation:
 lean 3 declaration is
-  forall {a : SignType}, Iff (LT.lt.{0} SignType (Preorder.toLT.{0} SignType (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) (OfNat.ofNat.{0} SignType 0 (OfNat.mk.{0} SignType 0 (Zero.zero.{0} SignType SignType.hasZero))) a) (Eq.{1} SignType a (OfNat.ofNat.{0} SignType 1 (OfNat.mk.{0} SignType 1 (One.one.{0} SignType SignType.hasOne))))
+  forall {a : SignType}, Iff (LT.lt.{0} SignType (Preorder.toHasLt.{0} SignType (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) (OfNat.ofNat.{0} SignType 0 (OfNat.mk.{0} SignType 0 (Zero.zero.{0} SignType SignType.hasZero))) a) (Eq.{1} SignType a (OfNat.ofNat.{0} SignType 1 (OfNat.mk.{0} SignType 1 (One.one.{0} SignType SignType.hasOne))))
 but is expected to have type
   forall {a : SignType}, Iff (LT.lt.{0} SignType (Preorder.toLT.{0} SignType (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (DistribLattice.toLattice.{0} SignType (instDistribLattice.{0} SignType SignType.instLinearOrderSignType)))))) (OfNat.ofNat.{0} SignType 0 (Zero.toOfNat0.{0} SignType SignType.instZeroSignType)) a) (Eq.{1} SignType a (OfNat.ofNat.{0} SignType 1 (One.toOfNat1.{0} SignType SignType.instOneSignType)))
 Case conversion may be inaccurate. Consider using '#align sign_type.pos_iff SignType.pos_iffₓ'. -/
@@ -241,7 +241,7 @@ theorem le_one (a : SignType) : a ≤ 1 :=
 
 /- warning: sign_type.not_lt_neg_one -> SignType.not_lt_neg_one is a dubious translation:
 lean 3 declaration is
-  forall (a : SignType), Not (LT.lt.{0} SignType (Preorder.toLT.{0} SignType (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) a (Neg.neg.{0} SignType SignType.hasNeg (OfNat.ofNat.{0} SignType 1 (OfNat.mk.{0} SignType 1 (One.one.{0} SignType SignType.hasOne)))))
+  forall (a : SignType), Not (LT.lt.{0} SignType (Preorder.toHasLt.{0} SignType (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) a (Neg.neg.{0} SignType SignType.hasNeg (OfNat.ofNat.{0} SignType 1 (OfNat.mk.{0} SignType 1 (One.one.{0} SignType SignType.hasOne)))))
 but is expected to have type
   forall (a : SignType), Not (LT.lt.{0} SignType (Preorder.toLT.{0} SignType (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (DistribLattice.toLattice.{0} SignType (instDistribLattice.{0} SignType SignType.instLinearOrderSignType)))))) a (Neg.neg.{0} SignType SignType.instNegSignType (OfNat.ofNat.{0} SignType 1 (One.toOfNat1.{0} SignType SignType.instOneSignType))))
 Case conversion may be inaccurate. Consider using '#align sign_type.not_lt_neg_one SignType.not_lt_neg_oneₓ'. -/
@@ -252,7 +252,7 @@ theorem not_lt_neg_one (a : SignType) : ¬a < -1 :=
 
 /- warning: sign_type.not_one_lt -> SignType.not_one_lt is a dubious translation:
 lean 3 declaration is
-  forall (a : SignType), Not (LT.lt.{0} SignType (Preorder.toLT.{0} SignType (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) (OfNat.ofNat.{0} SignType 1 (OfNat.mk.{0} SignType 1 (One.one.{0} SignType SignType.hasOne))) a)
+  forall (a : SignType), Not (LT.lt.{0} SignType (Preorder.toHasLt.{0} SignType (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) (OfNat.ofNat.{0} SignType 1 (OfNat.mk.{0} SignType 1 (One.one.{0} SignType SignType.hasOne))) a)
 but is expected to have type
   forall (a : SignType), Not (LT.lt.{0} SignType (Preorder.toLT.{0} SignType (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (DistribLattice.toLattice.{0} SignType (instDistribLattice.{0} SignType SignType.instLinearOrderSignType)))))) (OfNat.ofNat.{0} SignType 1 (One.toOfNat1.{0} SignType SignType.instOneSignType)) a)
 Case conversion may be inaccurate. Consider using '#align sign_type.not_one_lt SignType.not_one_ltₓ'. -/
@@ -275,7 +275,7 @@ theorem neg_eq_self_iff (a : SignType) : -a = a ↔ a = 0 := by decide!
 
 /- warning: sign_type.neg_one_lt_one -> SignType.neg_one_lt_one is a dubious translation:
 lean 3 declaration is
-  LT.lt.{0} SignType (Preorder.toLT.{0} SignType (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) (Neg.neg.{0} SignType SignType.hasNeg (OfNat.ofNat.{0} SignType 1 (OfNat.mk.{0} SignType 1 (One.one.{0} SignType SignType.hasOne)))) (OfNat.ofNat.{0} SignType 1 (OfNat.mk.{0} SignType 1 (One.one.{0} SignType SignType.hasOne)))
+  LT.lt.{0} SignType (Preorder.toHasLt.{0} SignType (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) (Neg.neg.{0} SignType SignType.hasNeg (OfNat.ofNat.{0} SignType 1 (OfNat.mk.{0} SignType 1 (One.one.{0} SignType SignType.hasOne)))) (OfNat.ofNat.{0} SignType 1 (OfNat.mk.{0} SignType 1 (One.one.{0} SignType SignType.hasOne)))
 but is expected to have type
   LT.lt.{0} SignType (Preorder.toLT.{0} SignType (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (DistribLattice.toLattice.{0} SignType (instDistribLattice.{0} SignType SignType.instLinearOrderSignType)))))) (Neg.neg.{0} SignType SignType.instNegSignType (OfNat.ofNat.{0} SignType 1 (One.toOfNat1.{0} SignType SignType.instOneSignType))) (OfNat.ofNat.{0} SignType 1 (One.toOfNat1.{0} SignType SignType.instOneSignType))
 Case conversion may be inaccurate. Consider using '#align sign_type.neg_one_lt_one SignType.neg_one_lt_oneₓ'. -/
@@ -366,9 +366,9 @@ variable [Zero α] [Preorder α] [DecidableRel ((· < ·) : α → α → Prop)]
 
 /- warning: sign -> SignType.sign is a dubious translation:
 lean 3 declaration is
-  forall {α : Type.{u1}} [_inst_1 : Zero.{u1} α] [_inst_2 : Preorder.{u1} α] [_inst_3 : DecidableRel.{succ u1} α (LT.lt.{u1} α (Preorder.toLT.{u1} α _inst_2))], OrderHom.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))
+  forall {α : Type.{u1}} [_inst_1 : Zero.{u1} α] [_inst_2 : Preorder.{u1} α] [_inst_3 : DecidableRel.{succ u1} α (LT.lt.{u1} α (Preorder.toHasLt.{u1} α _inst_2))], OrderHom.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))
 but is expected to have type
-  forall {α : Type.{u1}} [_inst_1 : Zero.{u1} α] [_inst_2 : Preorder.{u1} α] [_inst_3 : DecidableRel.{succ u1} α (fun (x._@.Mathlib.Data.Sign._hyg.4987 : α) (x._@.Mathlib.Data.Sign._hyg.4989 : α) => LT.lt.{u1} α (Preorder.toLT.{u1} α _inst_2) x._@.Mathlib.Data.Sign._hyg.4987 x._@.Mathlib.Data.Sign._hyg.4989)], OrderHom.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (DistribLattice.toLattice.{0} SignType (instDistribLattice.{0} SignType SignType.instLinearOrderSignType)))))
+  forall {α : Type.{u1}} [_inst_1 : Zero.{u1} α] [_inst_2 : Preorder.{u1} α] [_inst_3 : DecidableRel.{succ u1} α (fun (x._@.Mathlib.Data.Sign._hyg.4988 : α) (x._@.Mathlib.Data.Sign._hyg.4990 : α) => LT.lt.{u1} α (Preorder.toLT.{u1} α _inst_2) x._@.Mathlib.Data.Sign._hyg.4988 x._@.Mathlib.Data.Sign._hyg.4990)], OrderHom.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (DistribLattice.toLattice.{0} SignType (instDistribLattice.{0} SignType SignType.instLinearOrderSignType)))))
 Case conversion may be inaccurate. Consider using '#align sign SignType.signₓ'. -/
 /-- The sign of an element is 1 if it's positive, -1 if negative, 0 otherwise. -/
 def SignType.sign : α →o SignType :=
@@ -381,32 +381,53 @@ def SignType.sign : α →o SignType :=
     · cases h₄ (h.trans_lt h₃)⟩
 #align sign SignType.sign
 
-#print sign_apply /-
+/- warning: sign_apply -> sign_apply is a dubious translation:
+lean 3 declaration is
+  forall {α : Type.{u1}} [_inst_1 : Zero.{u1} α] [_inst_2 : Preorder.{u1} α] [_inst_3 : DecidableRel.{succ u1} α (LT.lt.{u1} α (Preorder.toHasLt.{u1} α _inst_2))] {a : α}, Eq.{1} SignType (coeFn.{succ u1, succ u1} (OrderHom.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) (fun (_x : OrderHom.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) => α -> SignType) (OrderHom.hasCoeToFun.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) (SignType.sign.{u1} α _inst_1 _inst_2 (fun (a : α) (b : α) => _inst_3 a b)) a) (ite.{1} SignType (LT.lt.{u1} α (Preorder.toHasLt.{u1} α _inst_2) (OfNat.ofNat.{u1} α 0 (OfNat.mk.{u1} α 0 (Zero.zero.{u1} α _inst_1))) a) (_inst_3 (OfNat.ofNat.{u1} α 0 (OfNat.mk.{u1} α 0 (Zero.zero.{u1} α _inst_1))) a) (OfNat.ofNat.{0} SignType 1 (OfNat.mk.{0} SignType 1 (One.one.{0} SignType SignType.hasOne))) (ite.{1} SignType (LT.lt.{u1} α (Preorder.toHasLt.{u1} α _inst_2) a (OfNat.ofNat.{u1} α 0 (OfNat.mk.{u1} α 0 (Zero.zero.{u1} α _inst_1)))) (_inst_3 a (OfNat.ofNat.{u1} α 0 (OfNat.mk.{u1} α 0 (Zero.zero.{u1} α _inst_1)))) (Neg.neg.{0} SignType SignType.hasNeg (OfNat.ofNat.{0} SignType 1 (OfNat.mk.{0} SignType 1 (One.one.{0} SignType SignType.hasOne)))) (OfNat.ofNat.{0} SignType 0 (OfNat.mk.{0} SignType 0 (Zero.zero.{0} SignType SignType.hasZero)))))
+but is expected to have type
+  forall {α : Type.{u1}} [_inst_1 : Zero.{u1} α] [_inst_2 : Preorder.{u1} α] [_inst_3 : DecidableRel.{succ u1} α (fun (x._@.Mathlib.Data.Sign._hyg.5196 : α) (x._@.Mathlib.Data.Sign._hyg.5198 : α) => LT.lt.{u1} α (Preorder.toLT.{u1} α _inst_2) x._@.Mathlib.Data.Sign._hyg.5196 x._@.Mathlib.Data.Sign._hyg.5198)] {a : α}, Eq.{1} SignType (OrderHom.toFun.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (DistribLattice.toLattice.{0} SignType (instDistribLattice.{0} SignType SignType.instLinearOrderSignType))))) (SignType.sign.{u1} α _inst_1 _inst_2 (fun (a : α) (b : α) => _inst_3 a b)) a) (ite.{1} SignType (LT.lt.{u1} α (Preorder.toLT.{u1} α _inst_2) (OfNat.ofNat.{u1} α 0 (Zero.toOfNat0.{u1} α _inst_1)) a) (_inst_3 (OfNat.ofNat.{u1} α 0 (Zero.toOfNat0.{u1} α _inst_1)) a) (OfNat.ofNat.{0} SignType 1 (One.toOfNat1.{0} SignType SignType.instOneSignType)) (ite.{1} SignType (LT.lt.{u1} α (Preorder.toLT.{u1} α _inst_2) a (OfNat.ofNat.{u1} α 0 (Zero.toOfNat0.{u1} α _inst_1))) (_inst_3 a (OfNat.ofNat.{u1} α 0 (Zero.toOfNat0.{u1} α _inst_1))) (Neg.neg.{0} SignType SignType.instNegSignType (OfNat.ofNat.{0} SignType 1 (One.toOfNat1.{0} SignType SignType.instOneSignType))) (OfNat.ofNat.{0} SignType 0 (Zero.toOfNat0.{0} SignType SignType.instZeroSignType))))
+Case conversion may be inaccurate. Consider using '#align sign_apply sign_applyₓ'. -/
 theorem sign_apply : SignType.sign a = ite (0 < a) 1 (ite (a < 0) (-1) 0) :=
   rfl
 #align sign_apply sign_apply
--/
 
-#print sign_zero /-
+/- warning: sign_zero -> sign_zero is a dubious translation:
+lean 3 declaration is
+  forall {α : Type.{u1}} [_inst_1 : Zero.{u1} α] [_inst_2 : Preorder.{u1} α] [_inst_3 : DecidableRel.{succ u1} α (LT.lt.{u1} α (Preorder.toHasLt.{u1} α _inst_2))], Eq.{1} SignType (coeFn.{succ u1, succ u1} (OrderHom.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) (fun (_x : OrderHom.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) => α -> SignType) (OrderHom.hasCoeToFun.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) (SignType.sign.{u1} α _inst_1 _inst_2 (fun (a : α) (b : α) => _inst_3 a b)) (OfNat.ofNat.{u1} α 0 (OfNat.mk.{u1} α 0 (Zero.zero.{u1} α _inst_1)))) (OfNat.ofNat.{0} SignType 0 (OfNat.mk.{0} SignType 0 (Zero.zero.{0} SignType SignType.hasZero)))
+but is expected to have type
+  forall {α : Type.{u1}} [_inst_1 : Zero.{u1} α] [_inst_2 : Preorder.{u1} α] [_inst_3 : DecidableRel.{succ u1} α (fun (x._@.Mathlib.Data.Sign._hyg.5263 : α) (x._@.Mathlib.Data.Sign._hyg.5265 : α) => LT.lt.{u1} α (Preorder.toLT.{u1} α _inst_2) x._@.Mathlib.Data.Sign._hyg.5263 x._@.Mathlib.Data.Sign._hyg.5265)], Eq.{1} SignType (OrderHom.toFun.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (DistribLattice.toLattice.{0} SignType (instDistribLattice.{0} SignType SignType.instLinearOrderSignType))))) (SignType.sign.{u1} α _inst_1 _inst_2 (fun (a : α) (b : α) => _inst_3 a b)) (OfNat.ofNat.{u1} α 0 (Zero.toOfNat0.{u1} α _inst_1))) (OfNat.ofNat.{0} SignType 0 (Zero.toOfNat0.{0} SignType SignType.instZeroSignType))
+Case conversion may be inaccurate. Consider using '#align sign_zero sign_zeroₓ'. -/
 @[simp]
 theorem sign_zero : SignType.sign (0 : α) = 0 := by simp [sign_apply]
 #align sign_zero sign_zero
--/
 
-#print sign_pos /-
+/- warning: sign_pos -> sign_pos is a dubious translation:
+lean 3 declaration is
+  forall {α : Type.{u1}} [_inst_1 : Zero.{u1} α] [_inst_2 : Preorder.{u1} α] [_inst_3 : DecidableRel.{succ u1} α (LT.lt.{u1} α (Preorder.toHasLt.{u1} α _inst_2))] {a : α}, (LT.lt.{u1} α (Preorder.toHasLt.{u1} α _inst_2) (OfNat.ofNat.{u1} α 0 (OfNat.mk.{u1} α 0 (Zero.zero.{u1} α _inst_1))) a) -> (Eq.{1} SignType (coeFn.{succ u1, succ u1} (OrderHom.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) (fun (_x : OrderHom.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) => α -> SignType) (OrderHom.hasCoeToFun.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) (SignType.sign.{u1} α _inst_1 _inst_2 (fun (a : α) (b : α) => _inst_3 a b)) a) (OfNat.ofNat.{0} SignType 1 (OfNat.mk.{0} SignType 1 (One.one.{0} SignType SignType.hasOne))))
+but is expected to have type
+  forall {α : Type.{u1}} [_inst_1 : Zero.{u1} α] [_inst_2 : Preorder.{u1} α] [_inst_3 : DecidableRel.{succ u1} α (fun (x._@.Mathlib.Data.Sign._hyg.5311 : α) (x._@.Mathlib.Data.Sign._hyg.5313 : α) => LT.lt.{u1} α (Preorder.toLT.{u1} α _inst_2) x._@.Mathlib.Data.Sign._hyg.5311 x._@.Mathlib.Data.Sign._hyg.5313)] {a : α}, (LT.lt.{u1} α (Preorder.toLT.{u1} α _inst_2) (OfNat.ofNat.{u1} α 0 (Zero.toOfNat0.{u1} α _inst_1)) a) -> (Eq.{1} SignType (OrderHom.toFun.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (DistribLattice.toLattice.{0} SignType (instDistribLattice.{0} SignType SignType.instLinearOrderSignType))))) (SignType.sign.{u1} α _inst_1 _inst_2 (fun (a : α) (b : α) => _inst_3 a b)) a) (OfNat.ofNat.{0} SignType 1 (One.toOfNat1.{0} SignType SignType.instOneSignType)))
+Case conversion may be inaccurate. Consider using '#align sign_pos sign_posₓ'. -/
 @[simp]
 theorem sign_pos (ha : 0 < a) : SignType.sign a = 1 := by rwa [sign_apply, if_pos]
 #align sign_pos sign_pos
--/
 
-#print sign_neg /-
+/- warning: sign_neg -> sign_neg is a dubious translation:
+lean 3 declaration is
+  forall {α : Type.{u1}} [_inst_1 : Zero.{u1} α] [_inst_2 : Preorder.{u1} α] [_inst_3 : DecidableRel.{succ u1} α (LT.lt.{u1} α (Preorder.toHasLt.{u1} α _inst_2))] {a : α}, (LT.lt.{u1} α (Preorder.toHasLt.{u1} α _inst_2) a (OfNat.ofNat.{u1} α 0 (OfNat.mk.{u1} α 0 (Zero.zero.{u1} α _inst_1)))) -> (Eq.{1} SignType (coeFn.{succ u1, succ u1} (OrderHom.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) (fun (_x : OrderHom.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) => α -> SignType) (OrderHom.hasCoeToFun.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) (SignType.sign.{u1} α _inst_1 _inst_2 (fun (a : α) (b : α) => _inst_3 a b)) a) (Neg.neg.{0} SignType SignType.hasNeg (OfNat.ofNat.{0} SignType 1 (OfNat.mk.{0} SignType 1 (One.one.{0} SignType SignType.hasOne)))))
+but is expected to have type
+  forall {α : Type.{u1}} [_inst_1 : Zero.{u1} α] [_inst_2 : Preorder.{u1} α] [_inst_3 : DecidableRel.{succ u1} α (fun (x._@.Mathlib.Data.Sign._hyg.5392 : α) (x._@.Mathlib.Data.Sign._hyg.5394 : α) => LT.lt.{u1} α (Preorder.toLT.{u1} α _inst_2) x._@.Mathlib.Data.Sign._hyg.5392 x._@.Mathlib.Data.Sign._hyg.5394)] {a : α}, (LT.lt.{u1} α (Preorder.toLT.{u1} α _inst_2) a (OfNat.ofNat.{u1} α 0 (Zero.toOfNat0.{u1} α _inst_1))) -> (Eq.{1} SignType (OrderHom.toFun.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (DistribLattice.toLattice.{0} SignType (instDistribLattice.{0} SignType SignType.instLinearOrderSignType))))) (SignType.sign.{u1} α _inst_1 _inst_2 (fun (a : α) (b : α) => _inst_3 a b)) a) (Neg.neg.{0} SignType SignType.instNegSignType (OfNat.ofNat.{0} SignType 1 (One.toOfNat1.{0} SignType SignType.instOneSignType))))
+Case conversion may be inaccurate. Consider using '#align sign_neg sign_negₓ'. -/
 @[simp]
 theorem sign_neg (ha : a < 0) : SignType.sign a = -1 := by
   rwa [sign_apply, if_neg <| asymm ha, if_pos]
 #align sign_neg sign_neg
--/
 
-#print sign_eq_one_iff /-
+/- warning: sign_eq_one_iff -> sign_eq_one_iff is a dubious translation:
+lean 3 declaration is
+  forall {α : Type.{u1}} [_inst_1 : Zero.{u1} α] [_inst_2 : Preorder.{u1} α] [_inst_3 : DecidableRel.{succ u1} α (LT.lt.{u1} α (Preorder.toHasLt.{u1} α _inst_2))] {a : α}, Iff (Eq.{1} SignType (coeFn.{succ u1, succ u1} (OrderHom.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) (fun (_x : OrderHom.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) => α -> SignType) (OrderHom.hasCoeToFun.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) (SignType.sign.{u1} α _inst_1 _inst_2 (fun (a : α) (b : α) => _inst_3 a b)) a) (OfNat.ofNat.{0} SignType 1 (OfNat.mk.{0} SignType 1 (One.one.{0} SignType SignType.hasOne)))) (LT.lt.{u1} α (Preorder.toHasLt.{u1} α _inst_2) (OfNat.ofNat.{u1} α 0 (OfNat.mk.{u1} α 0 (Zero.zero.{u1} α _inst_1))) a)
+but is expected to have type
+  forall {α : Type.{u1}} [_inst_1 : Zero.{u1} α] [_inst_2 : Preorder.{u1} α] [_inst_3 : DecidableRel.{succ u1} α (fun (x._@.Mathlib.Data.Sign._hyg.5479 : α) (x._@.Mathlib.Data.Sign._hyg.5481 : α) => LT.lt.{u1} α (Preorder.toLT.{u1} α _inst_2) x._@.Mathlib.Data.Sign._hyg.5479 x._@.Mathlib.Data.Sign._hyg.5481)] {a : α}, Iff (Eq.{1} SignType (OrderHom.toFun.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (DistribLattice.toLattice.{0} SignType (instDistribLattice.{0} SignType SignType.instLinearOrderSignType))))) (SignType.sign.{u1} α _inst_1 _inst_2 (fun (a : α) (b : α) => _inst_3 a b)) a) (OfNat.ofNat.{0} SignType 1 (One.toOfNat1.{0} SignType SignType.instOneSignType))) (LT.lt.{u1} α (Preorder.toLT.{u1} α _inst_2) (OfNat.ofNat.{u1} α 0 (Zero.toOfNat0.{u1} α _inst_1)) a)
+Case conversion may be inaccurate. Consider using '#align sign_eq_one_iff sign_eq_one_iffₓ'. -/
 theorem sign_eq_one_iff : SignType.sign a = 1 ↔ 0 < a :=
   by
   refine' ⟨fun h => _, fun h => sign_pos h⟩
@@ -414,9 +435,13 @@ theorem sign_eq_one_iff : SignType.sign a = 1 ↔ 0 < a :=
   rw [sign_apply, if_neg hn] at h
   split_ifs  at h <;> simpa using h
 #align sign_eq_one_iff sign_eq_one_iff
--/
 
-#print sign_eq_neg_one_iff /-
+/- warning: sign_eq_neg_one_iff -> sign_eq_neg_one_iff is a dubious translation:
+lean 3 declaration is
+  forall {α : Type.{u1}} [_inst_1 : Zero.{u1} α] [_inst_2 : Preorder.{u1} α] [_inst_3 : DecidableRel.{succ u1} α (LT.lt.{u1} α (Preorder.toHasLt.{u1} α _inst_2))] {a : α}, Iff (Eq.{1} SignType (coeFn.{succ u1, succ u1} (OrderHom.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) (fun (_x : OrderHom.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) => α -> SignType) (OrderHom.hasCoeToFun.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) (SignType.sign.{u1} α _inst_1 _inst_2 (fun (a : α) (b : α) => _inst_3 a b)) a) (Neg.neg.{0} SignType SignType.hasNeg (OfNat.ofNat.{0} SignType 1 (OfNat.mk.{0} SignType 1 (One.one.{0} SignType SignType.hasOne))))) (LT.lt.{u1} α (Preorder.toHasLt.{u1} α _inst_2) a (OfNat.ofNat.{u1} α 0 (OfNat.mk.{u1} α 0 (Zero.zero.{u1} α _inst_1))))
+but is expected to have type
+  forall {α : Type.{u1}} [_inst_1 : Zero.{u1} α] [_inst_2 : Preorder.{u1} α] [_inst_3 : DecidableRel.{succ u1} α (fun (x._@.Mathlib.Data.Sign._hyg.5592 : α) (x._@.Mathlib.Data.Sign._hyg.5594 : α) => LT.lt.{u1} α (Preorder.toLT.{u1} α _inst_2) x._@.Mathlib.Data.Sign._hyg.5592 x._@.Mathlib.Data.Sign._hyg.5594)] {a : α}, Iff (Eq.{1} SignType (OrderHom.toFun.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (DistribLattice.toLattice.{0} SignType (instDistribLattice.{0} SignType SignType.instLinearOrderSignType))))) (SignType.sign.{u1} α _inst_1 _inst_2 (fun (a : α) (b : α) => _inst_3 a b)) a) (Neg.neg.{0} SignType SignType.instNegSignType (OfNat.ofNat.{0} SignType 1 (One.toOfNat1.{0} SignType SignType.instOneSignType)))) (LT.lt.{u1} α (Preorder.toLT.{u1} α _inst_2) a (OfNat.ofNat.{u1} α 0 (Zero.toOfNat0.{u1} α _inst_1)))
+Case conversion may be inaccurate. Consider using '#align sign_eq_neg_one_iff sign_eq_neg_one_iffₓ'. -/
 theorem sign_eq_neg_one_iff : SignType.sign a = -1 ↔ a < 0 :=
   by
   refine' ⟨fun h => _, fun h => sign_neg h⟩
@@ -426,7 +451,6 @@ theorem sign_eq_neg_one_iff : SignType.sign a = -1 ↔ a < 0 :=
   · exact h_2
   · simpa using h
 #align sign_eq_neg_one_iff sign_eq_neg_one_iff
--/
 
 end Preorder
 
@@ -481,9 +505,9 @@ variable [OrderedSemiring α] [DecidableRel ((· < ·) : α → α → Prop)] [N
 
 /- warning: sign_one -> sign_one is a dubious translation:
 lean 3 declaration is
-  forall {α : Type.{u1}} [_inst_1 : OrderedSemiring.{u1} α] [_inst_2 : DecidableRel.{succ u1} α (LT.lt.{u1} α (Preorder.toLT.{u1} α (PartialOrder.toPreorder.{u1} α (OrderedAddCommMonoid.toPartialOrder.{u1} α (OrderedSemiring.toOrderedAddCommMonoid.{u1} α _inst_1)))))] [_inst_3 : Nontrivial.{u1} α], Eq.{1} SignType (coeFn.{succ u1, succ u1} (OrderHom.{u1, 0} α SignType (PartialOrder.toPreorder.{u1} α (OrderedAddCommMonoid.toPartialOrder.{u1} α (OrderedSemiring.toOrderedAddCommMonoid.{u1} α _inst_1))) (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) (fun (_x : OrderHom.{u1, 0} α SignType (PartialOrder.toPreorder.{u1} α (OrderedAddCommMonoid.toPartialOrder.{u1} α (OrderedSemiring.toOrderedAddCommMonoid.{u1} α _inst_1))) (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) => α -> SignType) (OrderHom.hasCoeToFun.{u1, 0} α SignType (PartialOrder.toPreorder.{u1} α (OrderedAddCommMonoid.toPartialOrder.{u1} α (OrderedSemiring.toOrderedAddCommMonoid.{u1} α _inst_1))) (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) (SignType.sign.{u1} α (MulZeroClass.toHasZero.{u1} α (NonUnitalNonAssocSemiring.toMulZeroClass.{u1} α (NonAssocSemiring.toNonUnitalNonAssocSemiring.{u1} α (Semiring.toNonAssocSemiring.{u1} α (OrderedSemiring.toSemiring.{u1} α _inst_1))))) (PartialOrder.toPreorder.{u1} α (OrderedAddCommMonoid.toPartialOrder.{u1} α (OrderedSemiring.toOrderedAddCommMonoid.{u1} α _inst_1))) (fun (a : α) (b : α) => _inst_2 a b)) (OfNat.ofNat.{u1} α 1 (OfNat.mk.{u1} α 1 (One.one.{u1} α (AddMonoidWithOne.toOne.{u1} α (AddCommMonoidWithOne.toAddMonoidWithOne.{u1} α (NonAssocSemiring.toAddCommMonoidWithOne.{u1} α (Semiring.toNonAssocSemiring.{u1} α (OrderedSemiring.toSemiring.{u1} α _inst_1))))))))) (OfNat.ofNat.{0} SignType 1 (OfNat.mk.{0} SignType 1 (One.one.{0} SignType SignType.hasOne)))
+  forall {α : Type.{u1}} [_inst_1 : OrderedSemiring.{u1} α] [_inst_2 : DecidableRel.{succ u1} α (LT.lt.{u1} α (Preorder.toHasLt.{u1} α (PartialOrder.toPreorder.{u1} α (OrderedAddCommMonoid.toPartialOrder.{u1} α (OrderedSemiring.toOrderedAddCommMonoid.{u1} α _inst_1)))))] [_inst_3 : Nontrivial.{u1} α], Eq.{1} SignType (coeFn.{succ u1, succ u1} (OrderHom.{u1, 0} α SignType (PartialOrder.toPreorder.{u1} α (OrderedAddCommMonoid.toPartialOrder.{u1} α (OrderedSemiring.toOrderedAddCommMonoid.{u1} α _inst_1))) (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) (fun (_x : OrderHom.{u1, 0} α SignType (PartialOrder.toPreorder.{u1} α (OrderedAddCommMonoid.toPartialOrder.{u1} α (OrderedSemiring.toOrderedAddCommMonoid.{u1} α _inst_1))) (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) => α -> SignType) (OrderHom.hasCoeToFun.{u1, 0} α SignType (PartialOrder.toPreorder.{u1} α (OrderedAddCommMonoid.toPartialOrder.{u1} α (OrderedSemiring.toOrderedAddCommMonoid.{u1} α _inst_1))) (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) (SignType.sign.{u1} α (MulZeroClass.toHasZero.{u1} α (NonUnitalNonAssocSemiring.toMulZeroClass.{u1} α (NonAssocSemiring.toNonUnitalNonAssocSemiring.{u1} α (Semiring.toNonAssocSemiring.{u1} α (OrderedSemiring.toSemiring.{u1} α _inst_1))))) (PartialOrder.toPreorder.{u1} α (OrderedAddCommMonoid.toPartialOrder.{u1} α (OrderedSemiring.toOrderedAddCommMonoid.{u1} α _inst_1))) (fun (a : α) (b : α) => _inst_2 a b)) (OfNat.ofNat.{u1} α 1 (OfNat.mk.{u1} α 1 (One.one.{u1} α (AddMonoidWithOne.toOne.{u1} α (AddCommMonoidWithOne.toAddMonoidWithOne.{u1} α (NonAssocSemiring.toAddCommMonoidWithOne.{u1} α (Semiring.toNonAssocSemiring.{u1} α (OrderedSemiring.toSemiring.{u1} α _inst_1))))))))) (OfNat.ofNat.{0} SignType 1 (OfNat.mk.{0} SignType 1 (One.one.{0} SignType SignType.hasOne)))
 but is expected to have type
-  forall {α : Type.{u1}} [_inst_1 : OrderedSemiring.{u1} α] [_inst_2 : DecidableRel.{succ u1} α (fun (x._@.Mathlib.Data.Sign._hyg.5946 : α) (x._@.Mathlib.Data.Sign._hyg.5948 : α) => LT.lt.{u1} α (Preorder.toLT.{u1} α (PartialOrder.toPreorder.{u1} α (OrderedSemiring.toPartialOrder.{u1} α _inst_1))) x._@.Mathlib.Data.Sign._hyg.5946 x._@.Mathlib.Data.Sign._hyg.5948)] [_inst_3 : Nontrivial.{u1} α], Eq.{1} SignType (OrderHom.toFun.{u1, 0} α SignType (PartialOrder.toPreorder.{u1} α (OrderedSemiring.toPartialOrder.{u1} α _inst_1)) (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (DistribLattice.toLattice.{0} SignType (instDistribLattice.{0} SignType SignType.instLinearOrderSignType))))) (SignType.sign.{u1} α (MonoidWithZero.toZero.{u1} α (Semiring.toMonoidWithZero.{u1} α (OrderedSemiring.toSemiring.{u1} α _inst_1))) (PartialOrder.toPreorder.{u1} α (OrderedSemiring.toPartialOrder.{u1} α _inst_1)) (fun (a : α) (b : α) => _inst_2 a b)) (OfNat.ofNat.{u1} α 1 (One.toOfNat1.{u1} α (Semiring.toOne.{u1} α (OrderedSemiring.toSemiring.{u1} α _inst_1))))) (OfNat.ofNat.{0} SignType 1 (One.toOfNat1.{0} SignType SignType.instOneSignType))
+  forall {α : Type.{u1}} [_inst_1 : OrderedSemiring.{u1} α] [_inst_2 : DecidableRel.{succ u1} α (fun (x._@.Mathlib.Data.Sign._hyg.5947 : α) (x._@.Mathlib.Data.Sign._hyg.5949 : α) => LT.lt.{u1} α (Preorder.toLT.{u1} α (PartialOrder.toPreorder.{u1} α (OrderedSemiring.toPartialOrder.{u1} α _inst_1))) x._@.Mathlib.Data.Sign._hyg.5947 x._@.Mathlib.Data.Sign._hyg.5949)] [_inst_3 : Nontrivial.{u1} α], Eq.{1} SignType (OrderHom.toFun.{u1, 0} α SignType (PartialOrder.toPreorder.{u1} α (OrderedSemiring.toPartialOrder.{u1} α _inst_1)) (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (DistribLattice.toLattice.{0} SignType (instDistribLattice.{0} SignType SignType.instLinearOrderSignType))))) (SignType.sign.{u1} α (MonoidWithZero.toZero.{u1} α (Semiring.toMonoidWithZero.{u1} α (OrderedSemiring.toSemiring.{u1} α _inst_1))) (PartialOrder.toPreorder.{u1} α (OrderedSemiring.toPartialOrder.{u1} α _inst_1)) (fun (a : α) (b : α) => _inst_2 a b)) (OfNat.ofNat.{u1} α 1 (One.toOfNat1.{u1} α (Semiring.toOne.{u1} α (OrderedSemiring.toSemiring.{u1} α _inst_1))))) (OfNat.ofNat.{0} SignType 1 (One.toOfNat1.{0} SignType SignType.instOneSignType))
 Case conversion may be inaccurate. Consider using '#align sign_one sign_oneₓ'. -/
 @[simp]
 theorem sign_one : SignType.sign (1 : α) = 1 :=
@@ -550,9 +574,9 @@ variable [AddGroup α] [Preorder α] [DecidableRel ((· < ·) : α → α → Pr
 
 /- warning: left.sign_neg -> Left.sign_neg is a dubious translation:
 lean 3 declaration is
-  forall {α : Type.{u1}} [_inst_1 : AddGroup.{u1} α] [_inst_2 : Preorder.{u1} α] [_inst_3 : DecidableRel.{succ u1} α (LT.lt.{u1} α (Preorder.toLT.{u1} α _inst_2))] [_inst_4 : CovariantClass.{u1, u1} α α (HAdd.hAdd.{u1, u1, u1} α α α (instHAdd.{u1} α (AddZeroClass.toHasAdd.{u1} α (AddMonoid.toAddZeroClass.{u1} α (SubNegMonoid.toAddMonoid.{u1} α (AddGroup.toSubNegMonoid.{u1} α _inst_1)))))) (LT.lt.{u1} α (Preorder.toLT.{u1} α _inst_2))] (a : α), Eq.{1} SignType (coeFn.{succ u1, succ u1} (OrderHom.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) (fun (_x : OrderHom.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) => α -> SignType) (OrderHom.hasCoeToFun.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) (SignType.sign.{u1} α (AddZeroClass.toHasZero.{u1} α (AddMonoid.toAddZeroClass.{u1} α (SubNegMonoid.toAddMonoid.{u1} α (AddGroup.toSubNegMonoid.{u1} α _inst_1)))) _inst_2 (fun (a : α) (b : α) => _inst_3 a b)) (Neg.neg.{u1} α (SubNegMonoid.toHasNeg.{u1} α (AddGroup.toSubNegMonoid.{u1} α _inst_1)) a)) (Neg.neg.{0} SignType SignType.hasNeg (coeFn.{succ u1, succ u1} (OrderHom.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) (fun (_x : OrderHom.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) => α -> SignType) (OrderHom.hasCoeToFun.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) (SignType.sign.{u1} α (AddZeroClass.toHasZero.{u1} α (AddMonoid.toAddZeroClass.{u1} α (SubNegMonoid.toAddMonoid.{u1} α (AddGroup.toSubNegMonoid.{u1} α _inst_1)))) _inst_2 (fun (a : α) (b : α) => _inst_3 a b)) a))
+  forall {α : Type.{u1}} [_inst_1 : AddGroup.{u1} α] [_inst_2 : Preorder.{u1} α] [_inst_3 : DecidableRel.{succ u1} α (LT.lt.{u1} α (Preorder.toHasLt.{u1} α _inst_2))] [_inst_4 : CovariantClass.{u1, u1} α α (HAdd.hAdd.{u1, u1, u1} α α α (instHAdd.{u1} α (AddZeroClass.toHasAdd.{u1} α (AddMonoid.toAddZeroClass.{u1} α (SubNegMonoid.toAddMonoid.{u1} α (AddGroup.toSubNegMonoid.{u1} α _inst_1)))))) (LT.lt.{u1} α (Preorder.toHasLt.{u1} α _inst_2))] (a : α), Eq.{1} SignType (coeFn.{succ u1, succ u1} (OrderHom.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) (fun (_x : OrderHom.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) => α -> SignType) (OrderHom.hasCoeToFun.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) (SignType.sign.{u1} α (AddZeroClass.toHasZero.{u1} α (AddMonoid.toAddZeroClass.{u1} α (SubNegMonoid.toAddMonoid.{u1} α (AddGroup.toSubNegMonoid.{u1} α _inst_1)))) _inst_2 (fun (a : α) (b : α) => _inst_3 a b)) (Neg.neg.{u1} α (SubNegMonoid.toHasNeg.{u1} α (AddGroup.toSubNegMonoid.{u1} α _inst_1)) a)) (Neg.neg.{0} SignType SignType.hasNeg (coeFn.{succ u1, succ u1} (OrderHom.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) (fun (_x : OrderHom.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) => α -> SignType) (OrderHom.hasCoeToFun.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) (SignType.sign.{u1} α (AddZeroClass.toHasZero.{u1} α (AddMonoid.toAddZeroClass.{u1} α (SubNegMonoid.toAddMonoid.{u1} α (AddGroup.toSubNegMonoid.{u1} α _inst_1)))) _inst_2 (fun (a : α) (b : α) => _inst_3 a b)) a))
 but is expected to have type
-  forall {α : Type.{u1}} [_inst_1 : AddGroup.{u1} α] [_inst_2 : Preorder.{u1} α] [_inst_3 : DecidableRel.{succ u1} α (fun (x._@.Mathlib.Data.Sign._hyg.6467 : α) (x._@.Mathlib.Data.Sign._hyg.6469 : α) => LT.lt.{u1} α (Preorder.toLT.{u1} α _inst_2) x._@.Mathlib.Data.Sign._hyg.6467 x._@.Mathlib.Data.Sign._hyg.6469)] [_inst_4 : CovariantClass.{u1, u1} α α (fun (x._@.Mathlib.Data.Sign._hyg.6486 : α) (x._@.Mathlib.Data.Sign._hyg.6488 : α) => HAdd.hAdd.{u1, u1, u1} α α α (instHAdd.{u1} α (AddZeroClass.toAdd.{u1} α (AddMonoid.toAddZeroClass.{u1} α (SubNegMonoid.toAddMonoid.{u1} α (AddGroup.toSubNegMonoid.{u1} α _inst_1))))) x._@.Mathlib.Data.Sign._hyg.6486 x._@.Mathlib.Data.Sign._hyg.6488) (fun (x._@.Mathlib.Data.Sign._hyg.6501 : α) (x._@.Mathlib.Data.Sign._hyg.6503 : α) => LT.lt.{u1} α (Preorder.toLT.{u1} α _inst_2) x._@.Mathlib.Data.Sign._hyg.6501 x._@.Mathlib.Data.Sign._hyg.6503)] (a : α), Eq.{1} SignType (OrderHom.toFun.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (DistribLattice.toLattice.{0} SignType (instDistribLattice.{0} SignType SignType.instLinearOrderSignType))))) (SignType.sign.{u1} α (NegZeroClass.toZero.{u1} α (SubNegZeroMonoid.toNegZeroClass.{u1} α (SubtractionMonoid.toSubNegZeroMonoid.{u1} α (AddGroup.toSubtractionMonoid.{u1} α _inst_1)))) _inst_2 (fun (a : α) (b : α) => _inst_3 a b)) (Neg.neg.{u1} α (NegZeroClass.toNeg.{u1} α (SubNegZeroMonoid.toNegZeroClass.{u1} α (SubtractionMonoid.toSubNegZeroMonoid.{u1} α (AddGroup.toSubtractionMonoid.{u1} α _inst_1)))) a)) (Neg.neg.{0} SignType SignType.instNegSignType (OrderHom.toFun.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (DistribLattice.toLattice.{0} SignType (instDistribLattice.{0} SignType SignType.instLinearOrderSignType))))) (SignType.sign.{u1} α (NegZeroClass.toZero.{u1} α (SubNegZeroMonoid.toNegZeroClass.{u1} α (SubtractionMonoid.toSubNegZeroMonoid.{u1} α (AddGroup.toSubtractionMonoid.{u1} α _inst_1)))) _inst_2 (fun (a : α) (b : α) => _inst_3 a b)) a))
+  forall {α : Type.{u1}} [_inst_1 : AddGroup.{u1} α] [_inst_2 : Preorder.{u1} α] [_inst_3 : DecidableRel.{succ u1} α (fun (x._@.Mathlib.Data.Sign._hyg.6468 : α) (x._@.Mathlib.Data.Sign._hyg.6470 : α) => LT.lt.{u1} α (Preorder.toLT.{u1} α _inst_2) x._@.Mathlib.Data.Sign._hyg.6468 x._@.Mathlib.Data.Sign._hyg.6470)] [_inst_4 : CovariantClass.{u1, u1} α α (fun (x._@.Mathlib.Data.Sign._hyg.6487 : α) (x._@.Mathlib.Data.Sign._hyg.6489 : α) => HAdd.hAdd.{u1, u1, u1} α α α (instHAdd.{u1} α (AddZeroClass.toAdd.{u1} α (AddMonoid.toAddZeroClass.{u1} α (SubNegMonoid.toAddMonoid.{u1} α (AddGroup.toSubNegMonoid.{u1} α _inst_1))))) x._@.Mathlib.Data.Sign._hyg.6487 x._@.Mathlib.Data.Sign._hyg.6489) (fun (x._@.Mathlib.Data.Sign._hyg.6502 : α) (x._@.Mathlib.Data.Sign._hyg.6504 : α) => LT.lt.{u1} α (Preorder.toLT.{u1} α _inst_2) x._@.Mathlib.Data.Sign._hyg.6502 x._@.Mathlib.Data.Sign._hyg.6504)] (a : α), Eq.{1} SignType (OrderHom.toFun.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (DistribLattice.toLattice.{0} SignType (instDistribLattice.{0} SignType SignType.instLinearOrderSignType))))) (SignType.sign.{u1} α (NegZeroClass.toZero.{u1} α (SubNegZeroMonoid.toNegZeroClass.{u1} α (SubtractionMonoid.toSubNegZeroMonoid.{u1} α (AddGroup.toSubtractionMonoid.{u1} α _inst_1)))) _inst_2 (fun (a : α) (b : α) => _inst_3 a b)) (Neg.neg.{u1} α (NegZeroClass.toNeg.{u1} α (SubNegZeroMonoid.toNegZeroClass.{u1} α (SubtractionMonoid.toSubNegZeroMonoid.{u1} α (AddGroup.toSubtractionMonoid.{u1} α _inst_1)))) a)) (Neg.neg.{0} SignType SignType.instNegSignType (OrderHom.toFun.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (DistribLattice.toLattice.{0} SignType (instDistribLattice.{0} SignType SignType.instLinearOrderSignType))))) (SignType.sign.{u1} α (NegZeroClass.toZero.{u1} α (SubNegZeroMonoid.toNegZeroClass.{u1} α (SubtractionMonoid.toSubNegZeroMonoid.{u1} α (AddGroup.toSubtractionMonoid.{u1} α _inst_1)))) _inst_2 (fun (a : α) (b : α) => _inst_3 a b)) a))
 Case conversion may be inaccurate. Consider using '#align left.sign_neg Left.sign_negₓ'. -/
 theorem Left.sign_neg [CovariantClass α α (· + ·) (· < ·)] (a : α) :
     SignType.sign (-a) = -SignType.sign a :=
@@ -567,9 +591,9 @@ theorem Left.sign_neg [CovariantClass α α (· + ·) (· < ·)] (a : α) :
 
 /- warning: right.sign_neg -> Right.sign_neg is a dubious translation:
 lean 3 declaration is
-  forall {α : Type.{u1}} [_inst_1 : AddGroup.{u1} α] [_inst_2 : Preorder.{u1} α] [_inst_3 : DecidableRel.{succ u1} α (LT.lt.{u1} α (Preorder.toLT.{u1} α _inst_2))] [_inst_4 : CovariantClass.{u1, u1} α α (Function.swap.{succ u1, succ u1, succ u1} α α (fun (ᾰ : α) (ᾰ : α) => α) (HAdd.hAdd.{u1, u1, u1} α α α (instHAdd.{u1} α (AddZeroClass.toHasAdd.{u1} α (AddMonoid.toAddZeroClass.{u1} α (SubNegMonoid.toAddMonoid.{u1} α (AddGroup.toSubNegMonoid.{u1} α _inst_1))))))) (LT.lt.{u1} α (Preorder.toLT.{u1} α _inst_2))] (a : α), Eq.{1} SignType (coeFn.{succ u1, succ u1} (OrderHom.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) (fun (_x : OrderHom.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) => α -> SignType) (OrderHom.hasCoeToFun.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) (SignType.sign.{u1} α (AddZeroClass.toHasZero.{u1} α (AddMonoid.toAddZeroClass.{u1} α (SubNegMonoid.toAddMonoid.{u1} α (AddGroup.toSubNegMonoid.{u1} α _inst_1)))) _inst_2 (fun (a : α) (b : α) => _inst_3 a b)) (Neg.neg.{u1} α (SubNegMonoid.toHasNeg.{u1} α (AddGroup.toSubNegMonoid.{u1} α _inst_1)) a)) (Neg.neg.{0} SignType SignType.hasNeg (coeFn.{succ u1, succ u1} (OrderHom.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) (fun (_x : OrderHom.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) => α -> SignType) (OrderHom.hasCoeToFun.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) (SignType.sign.{u1} α (AddZeroClass.toHasZero.{u1} α (AddMonoid.toAddZeroClass.{u1} α (SubNegMonoid.toAddMonoid.{u1} α (AddGroup.toSubNegMonoid.{u1} α _inst_1)))) _inst_2 (fun (a : α) (b : α) => _inst_3 a b)) a))
+  forall {α : Type.{u1}} [_inst_1 : AddGroup.{u1} α] [_inst_2 : Preorder.{u1} α] [_inst_3 : DecidableRel.{succ u1} α (LT.lt.{u1} α (Preorder.toHasLt.{u1} α _inst_2))] [_inst_4 : CovariantClass.{u1, u1} α α (Function.swap.{succ u1, succ u1, succ u1} α α (fun (ᾰ : α) (ᾰ : α) => α) (HAdd.hAdd.{u1, u1, u1} α α α (instHAdd.{u1} α (AddZeroClass.toHasAdd.{u1} α (AddMonoid.toAddZeroClass.{u1} α (SubNegMonoid.toAddMonoid.{u1} α (AddGroup.toSubNegMonoid.{u1} α _inst_1))))))) (LT.lt.{u1} α (Preorder.toHasLt.{u1} α _inst_2))] (a : α), Eq.{1} SignType (coeFn.{succ u1, succ u1} (OrderHom.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) (fun (_x : OrderHom.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) => α -> SignType) (OrderHom.hasCoeToFun.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) (SignType.sign.{u1} α (AddZeroClass.toHasZero.{u1} α (AddMonoid.toAddZeroClass.{u1} α (SubNegMonoid.toAddMonoid.{u1} α (AddGroup.toSubNegMonoid.{u1} α _inst_1)))) _inst_2 (fun (a : α) (b : α) => _inst_3 a b)) (Neg.neg.{u1} α (SubNegMonoid.toHasNeg.{u1} α (AddGroup.toSubNegMonoid.{u1} α _inst_1)) a)) (Neg.neg.{0} SignType SignType.hasNeg (coeFn.{succ u1, succ u1} (OrderHom.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) (fun (_x : OrderHom.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) => α -> SignType) (OrderHom.hasCoeToFun.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) (SignType.sign.{u1} α (AddZeroClass.toHasZero.{u1} α (AddMonoid.toAddZeroClass.{u1} α (SubNegMonoid.toAddMonoid.{u1} α (AddGroup.toSubNegMonoid.{u1} α _inst_1)))) _inst_2 (fun (a : α) (b : α) => _inst_3 a b)) a))
 but is expected to have type
-  forall {α : Type.{u1}} [_inst_1 : AddGroup.{u1} α] [_inst_2 : Preorder.{u1} α] [_inst_3 : DecidableRel.{succ u1} α (fun (x._@.Mathlib.Data.Sign._hyg.6585 : α) (x._@.Mathlib.Data.Sign._hyg.6587 : α) => LT.lt.{u1} α (Preorder.toLT.{u1} α _inst_2) x._@.Mathlib.Data.Sign._hyg.6585 x._@.Mathlib.Data.Sign._hyg.6587)] [_inst_4 : CovariantClass.{u1, u1} α α (Function.swap.{succ u1, succ u1, succ u1} α α (fun (ᾰ : α) (ᾰ : α) => α) (fun (x._@.Mathlib.Data.Sign._hyg.6607 : α) (x._@.Mathlib.Data.Sign._hyg.6609 : α) => HAdd.hAdd.{u1, u1, u1} α α α (instHAdd.{u1} α (AddZeroClass.toAdd.{u1} α (AddMonoid.toAddZeroClass.{u1} α (SubNegMonoid.toAddMonoid.{u1} α (AddGroup.toSubNegMonoid.{u1} α _inst_1))))) x._@.Mathlib.Data.Sign._hyg.6607 x._@.Mathlib.Data.Sign._hyg.6609)) (fun (x._@.Mathlib.Data.Sign._hyg.6622 : α) (x._@.Mathlib.Data.Sign._hyg.6624 : α) => LT.lt.{u1} α (Preorder.toLT.{u1} α _inst_2) x._@.Mathlib.Data.Sign._hyg.6622 x._@.Mathlib.Data.Sign._hyg.6624)] (a : α), Eq.{1} SignType (OrderHom.toFun.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (DistribLattice.toLattice.{0} SignType (instDistribLattice.{0} SignType SignType.instLinearOrderSignType))))) (SignType.sign.{u1} α (NegZeroClass.toZero.{u1} α (SubNegZeroMonoid.toNegZeroClass.{u1} α (SubtractionMonoid.toSubNegZeroMonoid.{u1} α (AddGroup.toSubtractionMonoid.{u1} α _inst_1)))) _inst_2 (fun (a : α) (b : α) => _inst_3 a b)) (Neg.neg.{u1} α (NegZeroClass.toNeg.{u1} α (SubNegZeroMonoid.toNegZeroClass.{u1} α (SubtractionMonoid.toSubNegZeroMonoid.{u1} α (AddGroup.toSubtractionMonoid.{u1} α _inst_1)))) a)) (Neg.neg.{0} SignType SignType.instNegSignType (OrderHom.toFun.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (DistribLattice.toLattice.{0} SignType (instDistribLattice.{0} SignType SignType.instLinearOrderSignType))))) (SignType.sign.{u1} α (NegZeroClass.toZero.{u1} α (SubNegZeroMonoid.toNegZeroClass.{u1} α (SubtractionMonoid.toSubNegZeroMonoid.{u1} α (AddGroup.toSubtractionMonoid.{u1} α _inst_1)))) _inst_2 (fun (a : α) (b : α) => _inst_3 a b)) a))
+  forall {α : Type.{u1}} [_inst_1 : AddGroup.{u1} α] [_inst_2 : Preorder.{u1} α] [_inst_3 : DecidableRel.{succ u1} α (fun (x._@.Mathlib.Data.Sign._hyg.6586 : α) (x._@.Mathlib.Data.Sign._hyg.6588 : α) => LT.lt.{u1} α (Preorder.toLT.{u1} α _inst_2) x._@.Mathlib.Data.Sign._hyg.6586 x._@.Mathlib.Data.Sign._hyg.6588)] [_inst_4 : CovariantClass.{u1, u1} α α (Function.swap.{succ u1, succ u1, succ u1} α α (fun (ᾰ : α) (ᾰ : α) => α) (fun (x._@.Mathlib.Data.Sign._hyg.6608 : α) (x._@.Mathlib.Data.Sign._hyg.6610 : α) => HAdd.hAdd.{u1, u1, u1} α α α (instHAdd.{u1} α (AddZeroClass.toAdd.{u1} α (AddMonoid.toAddZeroClass.{u1} α (SubNegMonoid.toAddMonoid.{u1} α (AddGroup.toSubNegMonoid.{u1} α _inst_1))))) x._@.Mathlib.Data.Sign._hyg.6608 x._@.Mathlib.Data.Sign._hyg.6610)) (fun (x._@.Mathlib.Data.Sign._hyg.6623 : α) (x._@.Mathlib.Data.Sign._hyg.6625 : α) => LT.lt.{u1} α (Preorder.toLT.{u1} α _inst_2) x._@.Mathlib.Data.Sign._hyg.6623 x._@.Mathlib.Data.Sign._hyg.6625)] (a : α), Eq.{1} SignType (OrderHom.toFun.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (DistribLattice.toLattice.{0} SignType (instDistribLattice.{0} SignType SignType.instLinearOrderSignType))))) (SignType.sign.{u1} α (NegZeroClass.toZero.{u1} α (SubNegZeroMonoid.toNegZeroClass.{u1} α (SubtractionMonoid.toSubNegZeroMonoid.{u1} α (AddGroup.toSubtractionMonoid.{u1} α _inst_1)))) _inst_2 (fun (a : α) (b : α) => _inst_3 a b)) (Neg.neg.{u1} α (NegZeroClass.toNeg.{u1} α (SubNegZeroMonoid.toNegZeroClass.{u1} α (SubtractionMonoid.toSubNegZeroMonoid.{u1} α (AddGroup.toSubtractionMonoid.{u1} α _inst_1)))) a)) (Neg.neg.{0} SignType SignType.instNegSignType (OrderHom.toFun.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (DistribLattice.toLattice.{0} SignType (instDistribLattice.{0} SignType SignType.instLinearOrderSignType))))) (SignType.sign.{u1} α (NegZeroClass.toZero.{u1} α (SubNegZeroMonoid.toNegZeroClass.{u1} α (SubtractionMonoid.toSubNegZeroMonoid.{u1} α (AddGroup.toSubtractionMonoid.{u1} α _inst_1)))) _inst_2 (fun (a : α) (b : α) => _inst_3 a b)) a))
 Case conversion may be inaccurate. Consider using '#align right.sign_neg Right.sign_negₓ'. -/
 theorem Right.sign_neg [CovariantClass α α (Function.swap (· + ·)) (· < ·)] (a : α) :
     SignType.sign (-a) = -SignType.sign a :=

mathlib commit https://github.com/leanprover-community/mathlib/commit/7ad820c4997738e2f542f8a20f32911f52020e26

@@ -504,7 +504,7 @@ attribute [local instance] LinearOrderedRing.decidableLt
 lean 3 declaration is
   forall {α : Type.{u1}} [_inst_1 : LinearOrderedRing.{u1} α] (x : α) (y : α), Eq.{1} SignType (coeFn.{succ u1, succ u1} (OrderHom.{u1, 0} α SignType (PartialOrder.toPreorder.{u1} α (OrderedAddCommGroup.toPartialOrder.{u1} α (StrictOrderedRing.toOrderedAddCommGroup.{u1} α (LinearOrderedRing.toStrictOrderedRing.{u1} α _inst_1)))) (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) (fun (_x : OrderHom.{u1, 0} α SignType (PartialOrder.toPreorder.{u1} α (OrderedAddCommGroup.toPartialOrder.{u1} α (StrictOrderedRing.toOrderedAddCommGroup.{u1} α (LinearOrderedRing.toStrictOrderedRing.{u1} α _inst_1)))) (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) => α -> SignType) (OrderHom.hasCoeToFun.{u1, 0} α SignType (PartialOrder.toPreorder.{u1} α (OrderedAddCommGroup.toPartialOrder.{u1} α (StrictOrderedRing.toOrderedAddCommGroup.{u1} α (LinearOrderedRing.toStrictOrderedRing.{u1} α _inst_1)))) (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) (SignType.sign.{u1} α (MulZeroClass.toHasZero.{u1} α (NonUnitalNonAssocSemiring.toMulZeroClass.{u1} α (NonUnitalNonAssocRing.toNonUnitalNonAssocSemiring.{u1} α (NonAssocRing.toNonUnitalNonAssocRing.{u1} α (Ring.toNonAssocRing.{u1} α (StrictOrderedRing.toRing.{u1} α (LinearOrderedRing.toStrictOrderedRing.{u1} α _inst_1))))))) (PartialOrder.toPreorder.{u1} α (OrderedAddCommGroup.toPartialOrder.{u1} α (StrictOrderedRing.toOrderedAddCommGroup.{u1} α (LinearOrderedRing.toStrictOrderedRing.{u1} α _inst_1)))) (fun (a : α) (b : α) => LinearOrderedRing.decidableLt.{u1} α _inst_1 a b)) (HMul.hMul.{u1, u1, u1} α α α (instHMul.{u1} α (Distrib.toHasMul.{u1} α (Ring.toDistrib.{u1} α (StrictOrderedRing.toRing.{u1} α (LinearOrderedRing.toStrictOrderedRing.{u1} α _inst_1))))) x y)) (HMul.hMul.{0, 0, 0} SignType SignType SignType (instHMul.{0} SignType SignType.hasMul) (coeFn.{succ u1, succ u1} (OrderHom.{u1, 0} α SignType (PartialOrder.toPreorder.{u1} α (OrderedAddCommGroup.toPartialOrder.{u1} α (StrictOrderedRing.toOrderedAddCommGroup.{u1} α (LinearOrderedRing.toStrictOrderedRing.{u1} α _inst_1)))) (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) (fun (_x : OrderHom.{u1, 0} α SignType (PartialOrder.toPreorder.{u1} α (OrderedAddCommGroup.toPartialOrder.{u1} α (StrictOrderedRing.toOrderedAddCommGroup.{u1} α (LinearOrderedRing.toStrictOrderedRing.{u1} α _inst_1)))) (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) => α -> SignType) (OrderHom.hasCoeToFun.{u1, 0} α SignType (PartialOrder.toPreorder.{u1} α (OrderedAddCommGroup.toPartialOrder.{u1} α (StrictOrderedRing.toOrderedAddCommGroup.{u1} α (LinearOrderedRing.toStrictOrderedRing.{u1} α _inst_1)))) (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) (SignType.sign.{u1} α (MulZeroClass.toHasZero.{u1} α (NonUnitalNonAssocSemiring.toMulZeroClass.{u1} α (NonUnitalNonAssocRing.toNonUnitalNonAssocSemiring.{u1} α (NonAssocRing.toNonUnitalNonAssocRing.{u1} α (Ring.toNonAssocRing.{u1} α (StrictOrderedRing.toRing.{u1} α (LinearOrderedRing.toStrictOrderedRing.{u1} α _inst_1))))))) (PartialOrder.toPreorder.{u1} α (OrderedAddCommGroup.toPartialOrder.{u1} α (StrictOrderedRing.toOrderedAddCommGroup.{u1} α (LinearOrderedRing.toStrictOrderedRing.{u1} α _inst_1)))) (fun (a : α) (b : α) => LinearOrderedRing.decidableLt.{u1} α _inst_1 a b)) x) (coeFn.{succ u1, succ u1} (OrderHom.{u1, 0} α SignType (PartialOrder.toPreorder.{u1} α (OrderedAddCommGroup.toPartialOrder.{u1} α (StrictOrderedRing.toOrderedAddCommGroup.{u1} α (LinearOrderedRing.toStrictOrderedRing.{u1} α _inst_1)))) (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) (fun (_x : OrderHom.{u1, 0} α SignType (PartialOrder.toPreorder.{u1} α (OrderedAddCommGroup.toPartialOrder.{u1} α (StrictOrderedRing.toOrderedAddCommGroup.{u1} α (LinearOrderedRing.toStrictOrderedRing.{u1} α _inst_1)))) (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) => α -> SignType) (OrderHom.hasCoeToFun.{u1, 0} α SignType (PartialOrder.toPreorder.{u1} α (OrderedAddCommGroup.toPartialOrder.{u1} α (StrictOrderedRing.toOrderedAddCommGroup.{u1} α (LinearOrderedRing.toStrictOrderedRing.{u1} α _inst_1)))) (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) (SignType.sign.{u1} α (MulZeroClass.toHasZero.{u1} α (NonUnitalNonAssocSemiring.toMulZeroClass.{u1} α (NonUnitalNonAssocRing.toNonUnitalNonAssocSemiring.{u1} α (NonAssocRing.toNonUnitalNonAssocRing.{u1} α (Ring.toNonAssocRing.{u1} α (StrictOrderedRing.toRing.{u1} α (LinearOrderedRing.toStrictOrderedRing.{u1} α _inst_1))))))) (PartialOrder.toPreorder.{u1} α (OrderedAddCommGroup.toPartialOrder.{u1} α (StrictOrderedRing.toOrderedAddCommGroup.{u1} α (LinearOrderedRing.toStrictOrderedRing.{u1} α _inst_1)))) (fun (a : α) (b : α) => LinearOrderedRing.decidableLt.{u1} α _inst_1 a b)) y))
 but is expected to have type
-  forall {α : Type.{u1}} [_inst_1 : LinearOrderedRing.{u1} α] (x : α) (y : α), Eq.{1} SignType (OrderHom.toFun.{u1, 0} α SignType (PartialOrder.toPreorder.{u1} α (StrictOrderedRing.toPartialOrder.{u1} α (LinearOrderedRing.toStrictOrderedRing.{u1} α _inst_1))) (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (DistribLattice.toLattice.{0} SignType (instDistribLattice.{0} SignType SignType.instLinearOrderSignType))))) (SignType.sign.{u1} α (MonoidWithZero.toZero.{u1} α (Semiring.toMonoidWithZero.{u1} α (StrictOrderedSemiring.toSemiring.{u1} α (LinearOrderedSemiring.toStrictOrderedSemiring.{u1} α (LinearOrderedRing.toLinearOrderedSemiring.{u1} α _inst_1))))) (PartialOrder.toPreorder.{u1} α (StrictOrderedRing.toPartialOrder.{u1} α (LinearOrderedRing.toStrictOrderedRing.{u1} α _inst_1))) (fun (a : α) (b : α) => LinearOrderedRing.decidable_lt.{u1} α _inst_1 a b)) (HMul.hMul.{u1, u1, u1} α α α (instHMul.{u1} α (NonUnitalNonAssocRing.toMul.{u1} α (NonAssocRing.toNonUnitalNonAssocRing.{u1} α (Ring.toNonAssocRing.{u1} α (StrictOrderedRing.toRing.{u1} α (LinearOrderedRing.toStrictOrderedRing.{u1} α _inst_1)))))) x y)) (HMul.hMul.{0, 0, 0} SignType SignType SignType (instHMul.{0} SignType SignType.instMulSignType) (OrderHom.toFun.{u1, 0} α SignType (PartialOrder.toPreorder.{u1} α (StrictOrderedRing.toPartialOrder.{u1} α (LinearOrderedRing.toStrictOrderedRing.{u1} α _inst_1))) (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (DistribLattice.toLattice.{0} SignType (instDistribLattice.{0} SignType SignType.instLinearOrderSignType))))) (SignType.sign.{u1} α (MonoidWithZero.toZero.{u1} α (Semiring.toMonoidWithZero.{u1} α (StrictOrderedSemiring.toSemiring.{u1} α (LinearOrderedSemiring.toStrictOrderedSemiring.{u1} α (LinearOrderedRing.toLinearOrderedSemiring.{u1} α _inst_1))))) (PartialOrder.toPreorder.{u1} α (StrictOrderedRing.toPartialOrder.{u1} α (LinearOrderedRing.toStrictOrderedRing.{u1} α _inst_1))) (fun (a : α) (b : α) => LinearOrderedRing.decidable_lt.{u1} α _inst_1 a b)) x) (OrderHom.toFun.{u1, 0} α SignType (PartialOrder.toPreorder.{u1} α (StrictOrderedRing.toPartialOrder.{u1} α (LinearOrderedRing.toStrictOrderedRing.{u1} α _inst_1))) (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (DistribLattice.toLattice.{0} SignType (instDistribLattice.{0} SignType SignType.instLinearOrderSignType))))) (SignType.sign.{u1} α (MonoidWithZero.toZero.{u1} α (Semiring.toMonoidWithZero.{u1} α (StrictOrderedSemiring.toSemiring.{u1} α (LinearOrderedSemiring.toStrictOrderedSemiring.{u1} α (LinearOrderedRing.toLinearOrderedSemiring.{u1} α _inst_1))))) (PartialOrder.toPreorder.{u1} α (StrictOrderedRing.toPartialOrder.{u1} α (LinearOrderedRing.toStrictOrderedRing.{u1} α _inst_1))) (fun (a : α) (b : α) => LinearOrderedRing.decidable_lt.{u1} α _inst_1 a b)) y))
+  forall {α : Type.{u1}} [_inst_1 : LinearOrderedRing.{u1} α] (x : α) (y : α), Eq.{1} SignType (OrderHom.toFun.{u1, 0} α SignType (PartialOrder.toPreorder.{u1} α (StrictOrderedRing.toPartialOrder.{u1} α (LinearOrderedRing.toStrictOrderedRing.{u1} α _inst_1))) (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (DistribLattice.toLattice.{0} SignType (instDistribLattice.{0} SignType SignType.instLinearOrderSignType))))) (SignType.sign.{u1} α (MonoidWithZero.toZero.{u1} α (Semiring.toMonoidWithZero.{u1} α (StrictOrderedSemiring.toSemiring.{u1} α (LinearOrderedSemiring.toStrictOrderedSemiring.{u1} α (LinearOrderedRing.toLinearOrderedSemiring.{u1} α _inst_1))))) (PartialOrder.toPreorder.{u1} α (StrictOrderedRing.toPartialOrder.{u1} α (LinearOrderedRing.toStrictOrderedRing.{u1} α _inst_1))) (fun (a : α) (b : α) => LinearOrderedRing.decidableLT.{u1} α _inst_1 a b)) (HMul.hMul.{u1, u1, u1} α α α (instHMul.{u1} α (NonUnitalNonAssocRing.toMul.{u1} α (NonAssocRing.toNonUnitalNonAssocRing.{u1} α (Ring.toNonAssocRing.{u1} α (StrictOrderedRing.toRing.{u1} α (LinearOrderedRing.toStrictOrderedRing.{u1} α _inst_1)))))) x y)) (HMul.hMul.{0, 0, 0} SignType SignType SignType (instHMul.{0} SignType SignType.instMulSignType) (OrderHom.toFun.{u1, 0} α SignType (PartialOrder.toPreorder.{u1} α (StrictOrderedRing.toPartialOrder.{u1} α (LinearOrderedRing.toStrictOrderedRing.{u1} α _inst_1))) (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (DistribLattice.toLattice.{0} SignType (instDistribLattice.{0} SignType SignType.instLinearOrderSignType))))) (SignType.sign.{u1} α (MonoidWithZero.toZero.{u1} α (Semiring.toMonoidWithZero.{u1} α (StrictOrderedSemiring.toSemiring.{u1} α (LinearOrderedSemiring.toStrictOrderedSemiring.{u1} α (LinearOrderedRing.toLinearOrderedSemiring.{u1} α _inst_1))))) (PartialOrder.toPreorder.{u1} α (StrictOrderedRing.toPartialOrder.{u1} α (LinearOrderedRing.toStrictOrderedRing.{u1} α _inst_1))) (fun (a : α) (b : α) => LinearOrderedRing.decidableLT.{u1} α _inst_1 a b)) x) (OrderHom.toFun.{u1, 0} α SignType (PartialOrder.toPreorder.{u1} α (StrictOrderedRing.toPartialOrder.{u1} α (LinearOrderedRing.toStrictOrderedRing.{u1} α _inst_1))) (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (DistribLattice.toLattice.{0} SignType (instDistribLattice.{0} SignType SignType.instLinearOrderSignType))))) (SignType.sign.{u1} α (MonoidWithZero.toZero.{u1} α (Semiring.toMonoidWithZero.{u1} α (StrictOrderedSemiring.toSemiring.{u1} α (LinearOrderedSemiring.toStrictOrderedSemiring.{u1} α (LinearOrderedRing.toLinearOrderedSemiring.{u1} α _inst_1))))) (PartialOrder.toPreorder.{u1} α (StrictOrderedRing.toPartialOrder.{u1} α (LinearOrderedRing.toStrictOrderedRing.{u1} α _inst_1))) (fun (a : α) (b : α) => LinearOrderedRing.decidableLT.{u1} α _inst_1 a b)) y))
 Case conversion may be inaccurate. Consider using '#align sign_mul sign_mulₓ'. -/
 theorem sign_mul (x y : α) : SignType.sign (x * y) = SignType.sign x * SignType.sign y := by
   rcases lt_trichotomy x 0 with (hx | hx | hx) <;> rcases lt_trichotomy y 0 with (hy | hy | hy) <;>
@@ -534,7 +534,7 @@ def signHom : α →*₀ SignType where
 lean 3 declaration is
   forall {α : Type.{u1}} [_inst_1 : LinearOrderedRing.{u1} α] (x : α) (n : Nat), Eq.{1} SignType (coeFn.{succ u1, succ u1} (OrderHom.{u1, 0} α SignType (PartialOrder.toPreorder.{u1} α (OrderedAddCommGroup.toPartialOrder.{u1} α (StrictOrderedRing.toOrderedAddCommGroup.{u1} α (LinearOrderedRing.toStrictOrderedRing.{u1} α _inst_1)))) (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) (fun (_x : OrderHom.{u1, 0} α SignType (PartialOrder.toPreorder.{u1} α (OrderedAddCommGroup.toPartialOrder.{u1} α (StrictOrderedRing.toOrderedAddCommGroup.{u1} α (LinearOrderedRing.toStrictOrderedRing.{u1} α _inst_1)))) (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) => α -> SignType) (OrderHom.hasCoeToFun.{u1, 0} α SignType (PartialOrder.toPreorder.{u1} α (OrderedAddCommGroup.toPartialOrder.{u1} α (StrictOrderedRing.toOrderedAddCommGroup.{u1} α (LinearOrderedRing.toStrictOrderedRing.{u1} α _inst_1)))) (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) (SignType.sign.{u1} α (MulZeroClass.toHasZero.{u1} α (NonUnitalNonAssocSemiring.toMulZeroClass.{u1} α (NonUnitalNonAssocRing.toNonUnitalNonAssocSemiring.{u1} α (NonAssocRing.toNonUnitalNonAssocRing.{u1} α (Ring.toNonAssocRing.{u1} α (StrictOrderedRing.toRing.{u1} α (LinearOrderedRing.toStrictOrderedRing.{u1} α _inst_1))))))) (PartialOrder.toPreorder.{u1} α (OrderedAddCommGroup.toPartialOrder.{u1} α (StrictOrderedRing.toOrderedAddCommGroup.{u1} α (LinearOrderedRing.toStrictOrderedRing.{u1} α _inst_1)))) (fun (a : α) (b : α) => LinearOrderedRing.decidableLt.{u1} α _inst_1 a b)) (HPow.hPow.{u1, 0, u1} α Nat α (instHPow.{u1, 0} α Nat (Monoid.Pow.{u1} α (Ring.toMonoid.{u1} α (StrictOrderedRing.toRing.{u1} α (LinearOrderedRing.toStrictOrderedRing.{u1} α _inst_1))))) x n)) (HPow.hPow.{0, 0, 0} SignType Nat SignType (instHPow.{0, 0} SignType Nat (Monoid.Pow.{0} SignType (MonoidWithZero.toMonoid.{0} SignType (GroupWithZero.toMonoidWithZero.{0} SignType (CommGroupWithZero.toGroupWithZero.{0} SignType SignType.commGroupWithZero))))) (coeFn.{succ u1, succ u1} (OrderHom.{u1, 0} α SignType (PartialOrder.toPreorder.{u1} α (OrderedAddCommGroup.toPartialOrder.{u1} α (StrictOrderedRing.toOrderedAddCommGroup.{u1} α (LinearOrderedRing.toStrictOrderedRing.{u1} α _inst_1)))) (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) (fun (_x : OrderHom.{u1, 0} α SignType (PartialOrder.toPreorder.{u1} α (OrderedAddCommGroup.toPartialOrder.{u1} α (StrictOrderedRing.toOrderedAddCommGroup.{u1} α (LinearOrderedRing.toStrictOrderedRing.{u1} α _inst_1)))) (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) => α -> SignType) (OrderHom.hasCoeToFun.{u1, 0} α SignType (PartialOrder.toPreorder.{u1} α (OrderedAddCommGroup.toPartialOrder.{u1} α (StrictOrderedRing.toOrderedAddCommGroup.{u1} α (LinearOrderedRing.toStrictOrderedRing.{u1} α _inst_1)))) (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) (SignType.sign.{u1} α (MulZeroClass.toHasZero.{u1} α (NonUnitalNonAssocSemiring.toMulZeroClass.{u1} α (NonUnitalNonAssocRing.toNonUnitalNonAssocSemiring.{u1} α (NonAssocRing.toNonUnitalNonAssocRing.{u1} α (Ring.toNonAssocRing.{u1} α (StrictOrderedRing.toRing.{u1} α (LinearOrderedRing.toStrictOrderedRing.{u1} α _inst_1))))))) (PartialOrder.toPreorder.{u1} α (OrderedAddCommGroup.toPartialOrder.{u1} α (StrictOrderedRing.toOrderedAddCommGroup.{u1} α (LinearOrderedRing.toStrictOrderedRing.{u1} α _inst_1)))) (fun (a : α) (b : α) => LinearOrderedRing.decidableLt.{u1} α _inst_1 a b)) x) n)
 but is expected to have type
-  forall {α : Type.{u1}} [_inst_1 : LinearOrderedRing.{u1} α] (x : α) (n : Nat), Eq.{1} SignType (OrderHom.toFun.{u1, 0} α SignType (PartialOrder.toPreorder.{u1} α (StrictOrderedRing.toPartialOrder.{u1} α (LinearOrderedRing.toStrictOrderedRing.{u1} α _inst_1))) (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (DistribLattice.toLattice.{0} SignType (instDistribLattice.{0} SignType SignType.instLinearOrderSignType))))) (SignType.sign.{u1} α (MonoidWithZero.toZero.{u1} α (Semiring.toMonoidWithZero.{u1} α (StrictOrderedSemiring.toSemiring.{u1} α (LinearOrderedSemiring.toStrictOrderedSemiring.{u1} α (LinearOrderedRing.toLinearOrderedSemiring.{u1} α _inst_1))))) (PartialOrder.toPreorder.{u1} α (StrictOrderedRing.toPartialOrder.{u1} α (LinearOrderedRing.toStrictOrderedRing.{u1} α _inst_1))) (fun (a : α) (b : α) => LinearOrderedRing.decidable_lt.{u1} α _inst_1 a b)) (HPow.hPow.{u1, 0, u1} α Nat α (instHPow.{u1, 0} α Nat (Monoid.Pow.{u1} α (MonoidWithZero.toMonoid.{u1} α (Semiring.toMonoidWithZero.{u1} α (StrictOrderedSemiring.toSemiring.{u1} α (LinearOrderedSemiring.toStrictOrderedSemiring.{u1} α (LinearOrderedRing.toLinearOrderedSemiring.{u1} α _inst_1))))))) x n)) (HPow.hPow.{0, 0, 0} SignType Nat SignType (instHPow.{0, 0} SignType Nat (Monoid.Pow.{0} SignType (MonoidWithZero.toMonoid.{0} SignType (GroupWithZero.toMonoidWithZero.{0} SignType (CommGroupWithZero.toGroupWithZero.{0} SignType SignType.instCommGroupWithZeroSignType))))) (OrderHom.toFun.{u1, 0} α SignType (PartialOrder.toPreorder.{u1} α (StrictOrderedRing.toPartialOrder.{u1} α (LinearOrderedRing.toStrictOrderedRing.{u1} α _inst_1))) (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (DistribLattice.toLattice.{0} SignType (instDistribLattice.{0} SignType SignType.instLinearOrderSignType))))) (SignType.sign.{u1} α (MonoidWithZero.toZero.{u1} α (Semiring.toMonoidWithZero.{u1} α (StrictOrderedSemiring.toSemiring.{u1} α (LinearOrderedSemiring.toStrictOrderedSemiring.{u1} α (LinearOrderedRing.toLinearOrderedSemiring.{u1} α _inst_1))))) (PartialOrder.toPreorder.{u1} α (StrictOrderedRing.toPartialOrder.{u1} α (LinearOrderedRing.toStrictOrderedRing.{u1} α _inst_1))) (fun (a : α) (b : α) => LinearOrderedRing.decidable_lt.{u1} α _inst_1 a b)) x) n)
+  forall {α : Type.{u1}} [_inst_1 : LinearOrderedRing.{u1} α] (x : α) (n : Nat), Eq.{1} SignType (OrderHom.toFun.{u1, 0} α SignType (PartialOrder.toPreorder.{u1} α (StrictOrderedRing.toPartialOrder.{u1} α (LinearOrderedRing.toStrictOrderedRing.{u1} α _inst_1))) (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (DistribLattice.toLattice.{0} SignType (instDistribLattice.{0} SignType SignType.instLinearOrderSignType))))) (SignType.sign.{u1} α (MonoidWithZero.toZero.{u1} α (Semiring.toMonoidWithZero.{u1} α (StrictOrderedSemiring.toSemiring.{u1} α (LinearOrderedSemiring.toStrictOrderedSemiring.{u1} α (LinearOrderedRing.toLinearOrderedSemiring.{u1} α _inst_1))))) (PartialOrder.toPreorder.{u1} α (StrictOrderedRing.toPartialOrder.{u1} α (LinearOrderedRing.toStrictOrderedRing.{u1} α _inst_1))) (fun (a : α) (b : α) => LinearOrderedRing.decidableLT.{u1} α _inst_1 a b)) (HPow.hPow.{u1, 0, u1} α Nat α (instHPow.{u1, 0} α Nat (Monoid.Pow.{u1} α (MonoidWithZero.toMonoid.{u1} α (Semiring.toMonoidWithZero.{u1} α (StrictOrderedSemiring.toSemiring.{u1} α (LinearOrderedSemiring.toStrictOrderedSemiring.{u1} α (LinearOrderedRing.toLinearOrderedSemiring.{u1} α _inst_1))))))) x n)) (HPow.hPow.{0, 0, 0} SignType Nat SignType (instHPow.{0, 0} SignType Nat (Monoid.Pow.{0} SignType (MonoidWithZero.toMonoid.{0} SignType (GroupWithZero.toMonoidWithZero.{0} SignType (CommGroupWithZero.toGroupWithZero.{0} SignType SignType.instCommGroupWithZeroSignType))))) (OrderHom.toFun.{u1, 0} α SignType (PartialOrder.toPreorder.{u1} α (StrictOrderedRing.toPartialOrder.{u1} α (LinearOrderedRing.toStrictOrderedRing.{u1} α _inst_1))) (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (DistribLattice.toLattice.{0} SignType (instDistribLattice.{0} SignType SignType.instLinearOrderSignType))))) (SignType.sign.{u1} α (MonoidWithZero.toZero.{u1} α (Semiring.toMonoidWithZero.{u1} α (StrictOrderedSemiring.toSemiring.{u1} α (LinearOrderedSemiring.toStrictOrderedSemiring.{u1} α (LinearOrderedRing.toLinearOrderedSemiring.{u1} α _inst_1))))) (PartialOrder.toPreorder.{u1} α (StrictOrderedRing.toPartialOrder.{u1} α (LinearOrderedRing.toStrictOrderedRing.{u1} α _inst_1))) (fun (a : α) (b : α) => LinearOrderedRing.decidableLT.{u1} α _inst_1 a b)) x) n)
 Case conversion may be inaccurate. Consider using '#align sign_pow sign_powₓ'. -/
 theorem sign_pow (x : α) (n : ℕ) : SignType.sign (x ^ n) = SignType.sign x ^ n :=
   by
@@ -598,7 +598,7 @@ attribute [local instance] LinearOrderedAddCommGroup.decidableLt
 lean 3 declaration is
   forall {α : Type.{u1}} [_inst_1 : LinearOrderedAddCommGroup.{u1} α] {ι : Type.{u2}} {s : Finset.{u2} ι} {f : ι -> α}, (Finset.Nonempty.{u2} ι s) -> (forall (t : SignType), (forall (i : ι), (Membership.Mem.{u2, u2} ι (Finset.{u2} ι) (Finset.hasMem.{u2} ι) i s) -> (Eq.{1} SignType (coeFn.{succ u1, succ u1} (OrderHom.{u1, 0} α SignType (PartialOrder.toPreorder.{u1} α (OrderedAddCommGroup.toPartialOrder.{u1} α (LinearOrderedAddCommGroup.toOrderedAddCommGroup.{u1} α _inst_1))) (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) (fun (_x : OrderHom.{u1, 0} α SignType (PartialOrder.toPreorder.{u1} α (OrderedAddCommGroup.toPartialOrder.{u1} α (LinearOrderedAddCommGroup.toOrderedAddCommGroup.{u1} α _inst_1))) (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) => α -> SignType) (OrderHom.hasCoeToFun.{u1, 0} α SignType (PartialOrder.toPreorder.{u1} α (OrderedAddCommGroup.toPartialOrder.{u1} α (LinearOrderedAddCommGroup.toOrderedAddCommGroup.{u1} α _inst_1))) (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) (SignType.sign.{u1} α (AddZeroClass.toHasZero.{u1} α (AddMonoid.toAddZeroClass.{u1} α (SubNegMonoid.toAddMonoid.{u1} α (AddGroup.toSubNegMonoid.{u1} α (AddCommGroup.toAddGroup.{u1} α (OrderedAddCommGroup.toAddCommGroup.{u1} α (LinearOrderedAddCommGroup.toOrderedAddCommGroup.{u1} α _inst_1))))))) (PartialOrder.toPreorder.{u1} α (OrderedAddCommGroup.toPartialOrder.{u1} α (LinearOrderedAddCommGroup.toOrderedAddCommGroup.{u1} α _inst_1))) (fun (a : α) (b : α) => LinearOrderedAddCommGroup.decidableLt.{u1} α _inst_1 a b)) (f i)) t)) -> (Eq.{1} SignType (coeFn.{succ u1, succ u1} (OrderHom.{u1, 0} α SignType (PartialOrder.toPreorder.{u1} α (OrderedAddCommGroup.toPartialOrder.{u1} α (LinearOrderedAddCommGroup.toOrderedAddCommGroup.{u1} α _inst_1))) (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) (fun (_x : OrderHom.{u1, 0} α SignType (PartialOrder.toPreorder.{u1} α (OrderedAddCommGroup.toPartialOrder.{u1} α (LinearOrderedAddCommGroup.toOrderedAddCommGroup.{u1} α _inst_1))) (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) => α -> SignType) (OrderHom.hasCoeToFun.{u1, 0} α SignType (PartialOrder.toPreorder.{u1} α (OrderedAddCommGroup.toPartialOrder.{u1} α (LinearOrderedAddCommGroup.toOrderedAddCommGroup.{u1} α _inst_1))) (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) (SignType.sign.{u1} α (AddZeroClass.toHasZero.{u1} α (AddMonoid.toAddZeroClass.{u1} α (SubNegMonoid.toAddMonoid.{u1} α (AddGroup.toSubNegMonoid.{u1} α (AddCommGroup.toAddGroup.{u1} α (OrderedAddCommGroup.toAddCommGroup.{u1} α (LinearOrderedAddCommGroup.toOrderedAddCommGroup.{u1} α _inst_1))))))) (PartialOrder.toPreorder.{u1} α (OrderedAddCommGroup.toPartialOrder.{u1} α (LinearOrderedAddCommGroup.toOrderedAddCommGroup.{u1} α _inst_1))) (fun (a : α) (b : α) => LinearOrderedAddCommGroup.decidableLt.{u1} α _inst_1 a b)) (Finset.sum.{u1, u2} α ι (AddCommGroup.toAddCommMonoid.{u1} α (OrderedAddCommGroup.toAddCommGroup.{u1} α (LinearOrderedAddCommGroup.toOrderedAddCommGroup.{u1} α _inst_1))) s (fun (i : ι) => f i))) t))
 but is expected to have type
-  forall {α : Type.{u1}} [_inst_1 : LinearOrderedAddCommGroup.{u1} α] {ι : Type.{u2}} {s : Finset.{u2} ι} {f : ι -> α}, (Finset.Nonempty.{u2} ι s) -> (forall (t : SignType), (forall (i : ι), (Membership.mem.{u2, u2} ι (Finset.{u2} ι) (Finset.instMembershipFinset.{u2} ι) i s) -> (Eq.{1} SignType (OrderHom.toFun.{u1, 0} α SignType (PartialOrder.toPreorder.{u1} α (OrderedAddCommGroup.toPartialOrder.{u1} α (LinearOrderedAddCommGroup.toOrderedAddCommGroup.{u1} α _inst_1))) (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (DistribLattice.toLattice.{0} SignType (instDistribLattice.{0} SignType SignType.instLinearOrderSignType))))) (SignType.sign.{u1} α (NegZeroClass.toZero.{u1} α (SubNegZeroMonoid.toNegZeroClass.{u1} α (SubtractionMonoid.toSubNegZeroMonoid.{u1} α (SubtractionCommMonoid.toSubtractionMonoid.{u1} α (AddCommGroup.toDivisionAddCommMonoid.{u1} α (OrderedAddCommGroup.toAddCommGroup.{u1} α (LinearOrderedAddCommGroup.toOrderedAddCommGroup.{u1} α _inst_1))))))) (PartialOrder.toPreorder.{u1} α (OrderedAddCommGroup.toPartialOrder.{u1} α (LinearOrderedAddCommGroup.toOrderedAddCommGroup.{u1} α _inst_1))) (fun (a : α) (b : α) => LinearOrderedAddCommGroup.decidable_lt.{u1} α _inst_1 a b)) (f i)) t)) -> (Eq.{1} SignType (OrderHom.toFun.{u1, 0} α SignType (PartialOrder.toPreorder.{u1} α (OrderedAddCommGroup.toPartialOrder.{u1} α (LinearOrderedAddCommGroup.toOrderedAddCommGroup.{u1} α _inst_1))) (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (DistribLattice.toLattice.{0} SignType (instDistribLattice.{0} SignType SignType.instLinearOrderSignType))))) (SignType.sign.{u1} α (NegZeroClass.toZero.{u1} α (SubNegZeroMonoid.toNegZeroClass.{u1} α (SubtractionMonoid.toSubNegZeroMonoid.{u1} α (SubtractionCommMonoid.toSubtractionMonoid.{u1} α (AddCommGroup.toDivisionAddCommMonoid.{u1} α (OrderedAddCommGroup.toAddCommGroup.{u1} α (LinearOrderedAddCommGroup.toOrderedAddCommGroup.{u1} α _inst_1))))))) (PartialOrder.toPreorder.{u1} α (OrderedAddCommGroup.toPartialOrder.{u1} α (LinearOrderedAddCommGroup.toOrderedAddCommGroup.{u1} α _inst_1))) (fun (a : α) (b : α) => LinearOrderedAddCommGroup.decidable_lt.{u1} α _inst_1 a b)) (Finset.sum.{u1, u2} α ι (OrderedCancelAddCommMonoid.toAddCommMonoid.{u1} α (LinearOrderedCancelAddCommMonoid.toOrderedCancelAddCommMonoid.{u1} α (LinearOrderedAddCommGroup.toLinearOrderedAddCancelCommMonoid.{u1} α _inst_1))) s (fun (i : ι) => f i))) t))
+  forall {α : Type.{u1}} [_inst_1 : LinearOrderedAddCommGroup.{u1} α] {ι : Type.{u2}} {s : Finset.{u2} ι} {f : ι -> α}, (Finset.Nonempty.{u2} ι s) -> (forall (t : SignType), (forall (i : ι), (Membership.mem.{u2, u2} ι (Finset.{u2} ι) (Finset.instMembershipFinset.{u2} ι) i s) -> (Eq.{1} SignType (OrderHom.toFun.{u1, 0} α SignType (PartialOrder.toPreorder.{u1} α (OrderedAddCommGroup.toPartialOrder.{u1} α (LinearOrderedAddCommGroup.toOrderedAddCommGroup.{u1} α _inst_1))) (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (DistribLattice.toLattice.{0} SignType (instDistribLattice.{0} SignType SignType.instLinearOrderSignType))))) (SignType.sign.{u1} α (NegZeroClass.toZero.{u1} α (SubNegZeroMonoid.toNegZeroClass.{u1} α (SubtractionMonoid.toSubNegZeroMonoid.{u1} α (SubtractionCommMonoid.toSubtractionMonoid.{u1} α (AddCommGroup.toDivisionAddCommMonoid.{u1} α (OrderedAddCommGroup.toAddCommGroup.{u1} α (LinearOrderedAddCommGroup.toOrderedAddCommGroup.{u1} α _inst_1))))))) (PartialOrder.toPreorder.{u1} α (OrderedAddCommGroup.toPartialOrder.{u1} α (LinearOrderedAddCommGroup.toOrderedAddCommGroup.{u1} α _inst_1))) (fun (a : α) (b : α) => LinearOrderedAddCommGroup.decidableLT.{u1} α _inst_1 a b)) (f i)) t)) -> (Eq.{1} SignType (OrderHom.toFun.{u1, 0} α SignType (PartialOrder.toPreorder.{u1} α (OrderedAddCommGroup.toPartialOrder.{u1} α (LinearOrderedAddCommGroup.toOrderedAddCommGroup.{u1} α _inst_1))) (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (DistribLattice.toLattice.{0} SignType (instDistribLattice.{0} SignType SignType.instLinearOrderSignType))))) (SignType.sign.{u1} α (NegZeroClass.toZero.{u1} α (SubNegZeroMonoid.toNegZeroClass.{u1} α (SubtractionMonoid.toSubNegZeroMonoid.{u1} α (SubtractionCommMonoid.toSubtractionMonoid.{u1} α (AddCommGroup.toDivisionAddCommMonoid.{u1} α (OrderedAddCommGroup.toAddCommGroup.{u1} α (LinearOrderedAddCommGroup.toOrderedAddCommGroup.{u1} α _inst_1))))))) (PartialOrder.toPreorder.{u1} α (OrderedAddCommGroup.toPartialOrder.{u1} α (LinearOrderedAddCommGroup.toOrderedAddCommGroup.{u1} α _inst_1))) (fun (a : α) (b : α) => LinearOrderedAddCommGroup.decidableLT.{u1} α _inst_1 a b)) (Finset.sum.{u1, u2} α ι (OrderedCancelAddCommMonoid.toAddCommMonoid.{u1} α (LinearOrderedCancelAddCommMonoid.toOrderedCancelAddCommMonoid.{u1} α (LinearOrderedAddCommGroup.toLinearOrderedAddCancelCommMonoid.{u1} α _inst_1))) s (fun (i : ι) => f i))) t))
 Case conversion may be inaccurate. Consider using '#align sign_sum sign_sumₓ'. -/
 theorem sign_sum {ι : Type _} {s : Finset ι} {f : ι → α} (hs : s.Nonempty) (t : SignType)
     (h : ∀ i ∈ s, SignType.sign (f i) = t) : SignType.sign (∑ i in s, f i) = t :=

mathlib commit https://github.com/leanprover-community/mathlib/commit/08e1d8d4d989df3a6df86f385e9053ec8a372cc1

@@ -517,7 +517,7 @@ theorem sign_mul (x y : α) : SignType.sign (x * y) = SignType.sign x * SignType
 lean 3 declaration is
   forall {α : Type.{u1}} [_inst_1 : LinearOrderedRing.{u1} α], MonoidWithZeroHom.{u1, 0} α SignType (NonAssocSemiring.toMulZeroOneClass.{u1} α (NonAssocRing.toNonAssocSemiring.{u1} α (Ring.toNonAssocRing.{u1} α (StrictOrderedRing.toRing.{u1} α (LinearOrderedRing.toStrictOrderedRing.{u1} α _inst_1))))) (MonoidWithZero.toMulZeroOneClass.{0} SignType (GroupWithZero.toMonoidWithZero.{0} SignType (CommGroupWithZero.toGroupWithZero.{0} SignType SignType.commGroupWithZero)))
 but is expected to have type
-  forall {α : Type.{u1}} [_inst_1 : LinearOrderedRing.{u1} α], MonoidWithZeroHom.{u1, 0} α SignType (NonAssocSemiring.toMulZeroOneClass.{u1} α (NonAssocRing.toNonAssocSemiring.{u1} α (Ring.toNonAssocRing.{u1} α (StrictOrderedRing.toRing.{u1} α (LinearOrderedRing.toStrictOrderedRing.{u1} α _inst_1))))) (MonoidWithZero.toMulZeroOneClass.{0} SignType (GroupWithZero.toMonoidWithZero.{0} SignType (CommGroupWithZero.toGroupWithZero.{0} SignType SignType.instCommGroupWithZeroSignType)))
+  forall {α : Type.{u1}} [_inst_1 : LinearOrderedRing.{u1} α], MonoidWithZeroHom.{u1, 0} α SignType (NonAssocSemiring.toMulZeroOneClass.{u1} α (Semiring.toNonAssocSemiring.{u1} α (StrictOrderedSemiring.toSemiring.{u1} α (LinearOrderedSemiring.toStrictOrderedSemiring.{u1} α (LinearOrderedRing.toLinearOrderedSemiring.{u1} α _inst_1))))) (MonoidWithZero.toMulZeroOneClass.{0} SignType (GroupWithZero.toMonoidWithZero.{0} SignType (CommGroupWithZero.toGroupWithZero.{0} SignType SignType.instCommGroupWithZeroSignType)))
 Case conversion may be inaccurate. Consider using '#align sign_hom signHomₓ'. -/
 /-- `sign` as a `monoid_with_zero_hom` for a nontrivial ordered semiring. Note that linearity
 is required; consider ℂ with the order `z ≤ w` iff they have the same imaginary part and
@@ -651,7 +651,7 @@ private theorem exists_signed_sum_aux [DecidableEq α] (s : Finset α) (f : α 
 lean 3 declaration is
   forall {α : Type.{u1}} [_inst_1 : DecidableEq.{succ u1} α] (s : Finset.{u1} α) (f : α -> Int), Exists.{succ (succ u1)} Type.{u1} (fun (β : Type.{u1}) => Exists.{succ u1} (Fintype.{u1} β) (fun (_x : Fintype.{u1} β) => Exists.{succ u1} (β -> SignType) (fun (sgn : β -> SignType) => Exists.{succ u1} (β -> α) (fun (g : β -> α) => And (forall (b : β), Membership.Mem.{u1, u1} α (Finset.{u1} α) (Finset.hasMem.{u1} α) (g b) s) (And (Eq.{1} Nat (Fintype.card.{u1} β _x) (Finset.sum.{0, u1} Nat α Nat.addCommMonoid s (fun (a : α) => Int.natAbs (f a)))) (forall (a : α), (Membership.Mem.{u1, u1} α (Finset.{u1} α) (Finset.hasMem.{u1} α) a s) -> (Eq.{1} Int (Finset.sum.{0, u1} Int β Int.addCommMonoid (Finset.univ.{u1} β _x) (fun (b : β) => ite.{1} Int (Eq.{succ u1} α (g b) a) (_inst_1 (g b) a) ((fun (a : Type) (b : Type) [self : HasLiftT.{1, 1} a b] => self.0) SignType Int (HasLiftT.mk.{1, 1} SignType Int (CoeTCₓ.coe.{1, 1} SignType Int (SignType.hasCoeT.{0} Int Int.hasZero Int.hasOne Int.hasNeg))) (sgn b)) (OfNat.ofNat.{0} Int 0 (OfNat.mk.{0} Int 0 (Zero.zero.{0} Int Int.hasZero))))) (f a))))))))
 but is expected to have type
-  forall {α : Type.{u1}} [_inst_1 : DecidableEq.{succ u1} α] (s : Finset.{u1} α) (f : α -> Int), Exists.{succ (succ u1)} Type.{u1} (fun (β : Type.{u1}) => Exists.{succ u1} (Fintype.{u1} β) (fun (_x : Fintype.{u1} β) => Exists.{succ u1} (β -> SignType) (fun (sgn : β -> SignType) => Exists.{succ u1} (β -> α) (fun (g : β -> α) => And (forall (b : β), Membership.mem.{u1, u1} α (Finset.{u1} α) (Finset.instMembershipFinset.{u1} α) (g b) s) (And (Eq.{1} Nat (Fintype.card.{u1} β _x) (Finset.sum.{0, u1} Nat α Nat.addCommMonoid s (fun (a : α) => Int.natAbs (f a)))) (forall (a : α), (Membership.mem.{u1, u1} α (Finset.{u1} α) (Finset.instMembershipFinset.{u1} α) a s) -> (Eq.{1} Int (Finset.sum.{0, u1} Int β Int.instAddCommMonoidInt (Finset.univ.{u1} β _x) (fun (b : β) => ite.{1} Int (Eq.{succ u1} α (g b) a) (_inst_1 (g b) a) (SignType.cast.{0} Int (CommMonoidWithZero.toZero.{0} Int (CancelCommMonoidWithZero.toCommMonoidWithZero.{0} Int (IsDomain.toCancelCommMonoidWithZero.{0} Int Int.instCommSemiringInt (LinearOrderedRing.isDomain.{0} Int (LinearOrderedCommRing.toLinearOrderedRing.{0} Int Int.linearOrderedCommRing))))) (NonAssocRing.toOne.{0} Int (Ring.toNonAssocRing.{0} Int Int.instRingInt)) Int.instNegInt (sgn b)) (OfNat.ofNat.{0} Int 0 (instOfNatInt 0)))) (f a))))))))
+  forall {α : Type.{u1}} [_inst_1 : DecidableEq.{succ u1} α] (s : Finset.{u1} α) (f : α -> Int), Exists.{succ (succ u1)} Type.{u1} (fun (β : Type.{u1}) => Exists.{succ u1} (Fintype.{u1} β) (fun (_x : Fintype.{u1} β) => Exists.{succ u1} (β -> SignType) (fun (sgn : β -> SignType) => Exists.{succ u1} (β -> α) (fun (g : β -> α) => And (forall (b : β), Membership.mem.{u1, u1} α (Finset.{u1} α) (Finset.instMembershipFinset.{u1} α) (g b) s) (And (Eq.{1} Nat (Fintype.card.{u1} β _x) (Finset.sum.{0, u1} Nat α Nat.addCommMonoid s (fun (a : α) => Int.natAbs (f a)))) (forall (a : α), (Membership.mem.{u1, u1} α (Finset.{u1} α) (Finset.instMembershipFinset.{u1} α) a s) -> (Eq.{1} Int (Finset.sum.{0, u1} Int β Int.instAddCommMonoidInt (Finset.univ.{u1} β _x) (fun (b : β) => ite.{1} Int (Eq.{succ u1} α (g b) a) (_inst_1 (g b) a) (SignType.cast.{0} Int (CommMonoidWithZero.toZero.{0} Int (CancelCommMonoidWithZero.toCommMonoidWithZero.{0} Int (IsDomain.toCancelCommMonoidWithZero.{0} Int Int.instCommSemiringInt (LinearOrderedRing.isDomain.{0} Int (LinearOrderedCommRing.toLinearOrderedRing.{0} Int Int.linearOrderedCommRing))))) (Semiring.toOne.{0} Int Int.instSemiringInt) Int.instNegInt (sgn b)) (OfNat.ofNat.{0} Int 0 (instOfNatInt 0)))) (f a))))))))
 Case conversion may be inaccurate. Consider using '#align exists_signed_sum exists_signed_sumₓ'. -/
 /-- We can decompose a sum of absolute value `n` into a sum of `n` signs. -/
 theorem exists_signed_sum [DecidableEq α] (s : Finset α) (f : α → ℤ) :
@@ -668,7 +668,7 @@ theorem exists_signed_sum [DecidableEq α] (s : Finset α) (f : α → ℤ) :
 lean 3 declaration is
   forall {α : Type.{u1}} [_inst_1 : Nonempty.{succ u1} α] [_inst_2 : DecidableEq.{succ u1} α] (s : Finset.{u1} α) (f : α -> Int) (n : Nat), (LE.le.{0} Nat Nat.hasLe (Finset.sum.{0, u1} Nat α Nat.addCommMonoid s (fun (i : α) => Int.natAbs (f i))) n) -> (Exists.{succ (succ u1)} Type.{u1} (fun (β : Type.{u1}) => Exists.{succ u1} (Fintype.{u1} β) (fun (_x : Fintype.{u1} β) => Exists.{succ u1} (β -> SignType) (fun (sgn : β -> SignType) => Exists.{succ u1} (β -> α) (fun (g : β -> α) => And (forall (b : β), (Not (Membership.Mem.{u1, u1} α (Finset.{u1} α) (Finset.hasMem.{u1} α) (g b) s)) -> (Eq.{1} SignType (sgn b) (OfNat.ofNat.{0} SignType 0 (OfNat.mk.{0} SignType 0 (Zero.zero.{0} SignType SignType.hasZero))))) (And (Eq.{1} Nat (Fintype.card.{u1} β _x) n) (forall (a : α), (Membership.Mem.{u1, u1} α (Finset.{u1} α) (Finset.hasMem.{u1} α) a s) -> (Eq.{1} Int (Finset.sum.{0, u1} Int β Int.addCommMonoid (Finset.univ.{u1} β _x) (fun (i : β) => ite.{1} Int (Eq.{succ u1} α (g i) a) (_inst_2 (g i) a) ((fun (a : Type) (b : Type) [self : HasLiftT.{1, 1} a b] => self.0) SignType Int (HasLiftT.mk.{1, 1} SignType Int (CoeTCₓ.coe.{1, 1} SignType Int (SignType.hasCoeT.{0} Int Int.hasZero Int.hasOne Int.hasNeg))) (sgn i)) (OfNat.ofNat.{0} Int 0 (OfNat.mk.{0} Int 0 (Zero.zero.{0} Int Int.hasZero))))) (f a)))))))))
 but is expected to have type
-  forall {α : Type.{u1}} [_inst_1 : Nonempty.{succ u1} α] [_inst_2 : DecidableEq.{succ u1} α] (s : Finset.{u1} α) (f : α -> Int) (n : Nat), (LE.le.{0} Nat instLENat (Finset.sum.{0, u1} Nat α Nat.addCommMonoid s (fun (i : α) => Int.natAbs (f i))) n) -> (Exists.{succ (succ u1)} Type.{u1} (fun (β : Type.{u1}) => Exists.{succ u1} (Fintype.{u1} β) (fun (_x : Fintype.{u1} β) => Exists.{succ u1} (β -> SignType) (fun (sgn : β -> SignType) => Exists.{succ u1} (β -> α) (fun (g : β -> α) => And (forall (b : β), (Not (Membership.mem.{u1, u1} α (Finset.{u1} α) (Finset.instMembershipFinset.{u1} α) (g b) s)) -> (Eq.{1} SignType (sgn b) (OfNat.ofNat.{0} SignType 0 (Zero.toOfNat0.{0} SignType SignType.instZeroSignType)))) (And (Eq.{1} Nat (Fintype.card.{u1} β _x) n) (forall (a : α), (Membership.mem.{u1, u1} α (Finset.{u1} α) (Finset.instMembershipFinset.{u1} α) a s) -> (Eq.{1} Int (Finset.sum.{0, u1} Int β Int.instAddCommMonoidInt (Finset.univ.{u1} β _x) (fun (i : β) => ite.{1} Int (Eq.{succ u1} α (g i) a) (_inst_2 (g i) a) (SignType.cast.{0} Int (CommMonoidWithZero.toZero.{0} Int (CancelCommMonoidWithZero.toCommMonoidWithZero.{0} Int (IsDomain.toCancelCommMonoidWithZero.{0} Int Int.instCommSemiringInt (LinearOrderedRing.isDomain.{0} Int (LinearOrderedCommRing.toLinearOrderedRing.{0} Int Int.linearOrderedCommRing))))) (NonAssocRing.toOne.{0} Int (Ring.toNonAssocRing.{0} Int Int.instRingInt)) Int.instNegInt (sgn i)) (OfNat.ofNat.{0} Int 0 (instOfNatInt 0)))) (f a)))))))))
+  forall {α : Type.{u1}} [_inst_1 : Nonempty.{succ u1} α] [_inst_2 : DecidableEq.{succ u1} α] (s : Finset.{u1} α) (f : α -> Int) (n : Nat), (LE.le.{0} Nat instLENat (Finset.sum.{0, u1} Nat α Nat.addCommMonoid s (fun (i : α) => Int.natAbs (f i))) n) -> (Exists.{succ (succ u1)} Type.{u1} (fun (β : Type.{u1}) => Exists.{succ u1} (Fintype.{u1} β) (fun (_x : Fintype.{u1} β) => Exists.{succ u1} (β -> SignType) (fun (sgn : β -> SignType) => Exists.{succ u1} (β -> α) (fun (g : β -> α) => And (forall (b : β), (Not (Membership.mem.{u1, u1} α (Finset.{u1} α) (Finset.instMembershipFinset.{u1} α) (g b) s)) -> (Eq.{1} SignType (sgn b) (OfNat.ofNat.{0} SignType 0 (Zero.toOfNat0.{0} SignType SignType.instZeroSignType)))) (And (Eq.{1} Nat (Fintype.card.{u1} β _x) n) (forall (a : α), (Membership.mem.{u1, u1} α (Finset.{u1} α) (Finset.instMembershipFinset.{u1} α) a s) -> (Eq.{1} Int (Finset.sum.{0, u1} Int β Int.instAddCommMonoidInt (Finset.univ.{u1} β _x) (fun (i : β) => ite.{1} Int (Eq.{succ u1} α (g i) a) (_inst_2 (g i) a) (SignType.cast.{0} Int (CommMonoidWithZero.toZero.{0} Int (CancelCommMonoidWithZero.toCommMonoidWithZero.{0} Int (IsDomain.toCancelCommMonoidWithZero.{0} Int Int.instCommSemiringInt (LinearOrderedRing.isDomain.{0} Int (LinearOrderedCommRing.toLinearOrderedRing.{0} Int Int.linearOrderedCommRing))))) (Semiring.toOne.{0} Int Int.instSemiringInt) Int.instNegInt (sgn i)) (OfNat.ofNat.{0} Int 0 (instOfNatInt 0)))) (f a)))))))))
 Case conversion may be inaccurate. Consider using '#align exists_signed_sum' exists_signed_sum'ₓ'. -/
 /-- We can decompose a sum of absolute value less than `n` into a sum of at most `n` signs. -/
 theorem exists_signed_sum' [Nonempty α] [DecidableEq α] (s : Finset α) (f : α → ℤ) (n : ℕ)

mathlib commit https://github.com/leanprover-community/mathlib/commit/36b8aa61ea7c05727161f96a0532897bd72aedab

@@ -569,7 +569,7 @@ theorem Left.sign_neg [CovariantClass α α (· + ·) (· < ·)] (a : α) :
 lean 3 declaration is
   forall {α : Type.{u1}} [_inst_1 : AddGroup.{u1} α] [_inst_2 : Preorder.{u1} α] [_inst_3 : DecidableRel.{succ u1} α (LT.lt.{u1} α (Preorder.toLT.{u1} α _inst_2))] [_inst_4 : CovariantClass.{u1, u1} α α (Function.swap.{succ u1, succ u1, succ u1} α α (fun (ᾰ : α) (ᾰ : α) => α) (HAdd.hAdd.{u1, u1, u1} α α α (instHAdd.{u1} α (AddZeroClass.toHasAdd.{u1} α (AddMonoid.toAddZeroClass.{u1} α (SubNegMonoid.toAddMonoid.{u1} α (AddGroup.toSubNegMonoid.{u1} α _inst_1))))))) (LT.lt.{u1} α (Preorder.toLT.{u1} α _inst_2))] (a : α), Eq.{1} SignType (coeFn.{succ u1, succ u1} (OrderHom.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) (fun (_x : OrderHom.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) => α -> SignType) (OrderHom.hasCoeToFun.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) (SignType.sign.{u1} α (AddZeroClass.toHasZero.{u1} α (AddMonoid.toAddZeroClass.{u1} α (SubNegMonoid.toAddMonoid.{u1} α (AddGroup.toSubNegMonoid.{u1} α _inst_1)))) _inst_2 (fun (a : α) (b : α) => _inst_3 a b)) (Neg.neg.{u1} α (SubNegMonoid.toHasNeg.{u1} α (AddGroup.toSubNegMonoid.{u1} α _inst_1)) a)) (Neg.neg.{0} SignType SignType.hasNeg (coeFn.{succ u1, succ u1} (OrderHom.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) (fun (_x : OrderHom.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) => α -> SignType) (OrderHom.hasCoeToFun.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) (SignType.sign.{u1} α (AddZeroClass.toHasZero.{u1} α (AddMonoid.toAddZeroClass.{u1} α (SubNegMonoid.toAddMonoid.{u1} α (AddGroup.toSubNegMonoid.{u1} α _inst_1)))) _inst_2 (fun (a : α) (b : α) => _inst_3 a b)) a))
 but is expected to have type
-  forall {α : Type.{u1}} [_inst_1 : AddGroup.{u1} α] [_inst_2 : Preorder.{u1} α] [_inst_3 : DecidableRel.{succ u1} α (fun (x._@.Mathlib.Data.Sign._hyg.6587 : α) (x._@.Mathlib.Data.Sign._hyg.6589 : α) => LT.lt.{u1} α (Preorder.toLT.{u1} α _inst_2) x._@.Mathlib.Data.Sign._hyg.6587 x._@.Mathlib.Data.Sign._hyg.6589)] [_inst_4 : CovariantClass.{u1, u1} α α (Function.swap.{succ u1, succ u1, succ u1} α α (fun (ᾰ : α) (ᾰ : α) => α) (fun (x._@.Mathlib.Data.Sign._hyg.6609 : α) (x._@.Mathlib.Data.Sign._hyg.6611 : α) => HAdd.hAdd.{u1, u1, u1} α α α (instHAdd.{u1} α (AddZeroClass.toAdd.{u1} α (AddMonoid.toAddZeroClass.{u1} α (SubNegMonoid.toAddMonoid.{u1} α (AddGroup.toSubNegMonoid.{u1} α _inst_1))))) x._@.Mathlib.Data.Sign._hyg.6609 x._@.Mathlib.Data.Sign._hyg.6611)) (fun (x._@.Mathlib.Data.Sign._hyg.6624 : α) (x._@.Mathlib.Data.Sign._hyg.6626 : α) => LT.lt.{u1} α (Preorder.toLT.{u1} α _inst_2) x._@.Mathlib.Data.Sign._hyg.6624 x._@.Mathlib.Data.Sign._hyg.6626)] (a : α), Eq.{1} SignType (OrderHom.toFun.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (DistribLattice.toLattice.{0} SignType (instDistribLattice.{0} SignType SignType.instLinearOrderSignType))))) (SignType.sign.{u1} α (NegZeroClass.toZero.{u1} α (SubNegZeroMonoid.toNegZeroClass.{u1} α (SubtractionMonoid.toSubNegZeroMonoid.{u1} α (AddGroup.toSubtractionMonoid.{u1} α _inst_1)))) _inst_2 (fun (a : α) (b : α) => _inst_3 a b)) (Neg.neg.{u1} α (NegZeroClass.toNeg.{u1} α (SubNegZeroMonoid.toNegZeroClass.{u1} α (SubtractionMonoid.toSubNegZeroMonoid.{u1} α (AddGroup.toSubtractionMonoid.{u1} α _inst_1)))) a)) (Neg.neg.{0} SignType SignType.instNegSignType (OrderHom.toFun.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (DistribLattice.toLattice.{0} SignType (instDistribLattice.{0} SignType SignType.instLinearOrderSignType))))) (SignType.sign.{u1} α (NegZeroClass.toZero.{u1} α (SubNegZeroMonoid.toNegZeroClass.{u1} α (SubtractionMonoid.toSubNegZeroMonoid.{u1} α (AddGroup.toSubtractionMonoid.{u1} α _inst_1)))) _inst_2 (fun (a : α) (b : α) => _inst_3 a b)) a))
+  forall {α : Type.{u1}} [_inst_1 : AddGroup.{u1} α] [_inst_2 : Preorder.{u1} α] [_inst_3 : DecidableRel.{succ u1} α (fun (x._@.Mathlib.Data.Sign._hyg.6585 : α) (x._@.Mathlib.Data.Sign._hyg.6587 : α) => LT.lt.{u1} α (Preorder.toLT.{u1} α _inst_2) x._@.Mathlib.Data.Sign._hyg.6585 x._@.Mathlib.Data.Sign._hyg.6587)] [_inst_4 : CovariantClass.{u1, u1} α α (Function.swap.{succ u1, succ u1, succ u1} α α (fun (ᾰ : α) (ᾰ : α) => α) (fun (x._@.Mathlib.Data.Sign._hyg.6607 : α) (x._@.Mathlib.Data.Sign._hyg.6609 : α) => HAdd.hAdd.{u1, u1, u1} α α α (instHAdd.{u1} α (AddZeroClass.toAdd.{u1} α (AddMonoid.toAddZeroClass.{u1} α (SubNegMonoid.toAddMonoid.{u1} α (AddGroup.toSubNegMonoid.{u1} α _inst_1))))) x._@.Mathlib.Data.Sign._hyg.6607 x._@.Mathlib.Data.Sign._hyg.6609)) (fun (x._@.Mathlib.Data.Sign._hyg.6622 : α) (x._@.Mathlib.Data.Sign._hyg.6624 : α) => LT.lt.{u1} α (Preorder.toLT.{u1} α _inst_2) x._@.Mathlib.Data.Sign._hyg.6622 x._@.Mathlib.Data.Sign._hyg.6624)] (a : α), Eq.{1} SignType (OrderHom.toFun.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (DistribLattice.toLattice.{0} SignType (instDistribLattice.{0} SignType SignType.instLinearOrderSignType))))) (SignType.sign.{u1} α (NegZeroClass.toZero.{u1} α (SubNegZeroMonoid.toNegZeroClass.{u1} α (SubtractionMonoid.toSubNegZeroMonoid.{u1} α (AddGroup.toSubtractionMonoid.{u1} α _inst_1)))) _inst_2 (fun (a : α) (b : α) => _inst_3 a b)) (Neg.neg.{u1} α (NegZeroClass.toNeg.{u1} α (SubNegZeroMonoid.toNegZeroClass.{u1} α (SubtractionMonoid.toSubNegZeroMonoid.{u1} α (AddGroup.toSubtractionMonoid.{u1} α _inst_1)))) a)) (Neg.neg.{0} SignType SignType.instNegSignType (OrderHom.toFun.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (DistribLattice.toLattice.{0} SignType (instDistribLattice.{0} SignType SignType.instLinearOrderSignType))))) (SignType.sign.{u1} α (NegZeroClass.toZero.{u1} α (SubNegZeroMonoid.toNegZeroClass.{u1} α (SubtractionMonoid.toSubNegZeroMonoid.{u1} α (AddGroup.toSubtractionMonoid.{u1} α _inst_1)))) _inst_2 (fun (a : α) (b : α) => _inst_3 a b)) a))
 Case conversion may be inaccurate. Consider using '#align right.sign_neg Right.sign_negₓ'. -/
 theorem Right.sign_neg [CovariantClass α α (Function.swap (· + ·)) (· < ·)] (a : α) :
     SignType.sign (-a) = -SignType.sign a :=

mathlib commit https://github.com/leanprover-community/mathlib/commit/728baa2f54e6062c5879a3e397ac6bac323e506f

@@ -368,7 +368,7 @@ variable [Zero α] [Preorder α] [DecidableRel ((· < ·) : α → α → Prop)]
 lean 3 declaration is
   forall {α : Type.{u1}} [_inst_1 : Zero.{u1} α] [_inst_2 : Preorder.{u1} α] [_inst_3 : DecidableRel.{succ u1} α (LT.lt.{u1} α (Preorder.toLT.{u1} α _inst_2))], OrderHom.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))
 but is expected to have type
-  forall {α : Type.{u1}} [_inst_1 : Zero.{u1} α] [_inst_2 : Preorder.{u1} α] [_inst_3 : DecidableRel.{succ u1} α (fun (x._@.Mathlib.Data.Sign._hyg.4949 : α) (x._@.Mathlib.Data.Sign._hyg.4951 : α) => LT.lt.{u1} α (Preorder.toLT.{u1} α _inst_2) x._@.Mathlib.Data.Sign._hyg.4949 x._@.Mathlib.Data.Sign._hyg.4951)], OrderHom.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (DistribLattice.toLattice.{0} SignType (instDistribLattice.{0} SignType SignType.instLinearOrderSignType)))))
+  forall {α : Type.{u1}} [_inst_1 : Zero.{u1} α] [_inst_2 : Preorder.{u1} α] [_inst_3 : DecidableRel.{succ u1} α (fun (x._@.Mathlib.Data.Sign._hyg.4987 : α) (x._@.Mathlib.Data.Sign._hyg.4989 : α) => LT.lt.{u1} α (Preorder.toLT.{u1} α _inst_2) x._@.Mathlib.Data.Sign._hyg.4987 x._@.Mathlib.Data.Sign._hyg.4989)], OrderHom.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (DistribLattice.toLattice.{0} SignType (instDistribLattice.{0} SignType SignType.instLinearOrderSignType)))))
 Case conversion may be inaccurate. Consider using '#align sign SignType.signₓ'. -/
 /-- The sign of an element is 1 if it's positive, -1 if negative, 0 otherwise. -/
 def SignType.sign : α →o SignType :=
@@ -483,7 +483,7 @@ variable [OrderedSemiring α] [DecidableRel ((· < ·) : α → α → Prop)] [N
 lean 3 declaration is
   forall {α : Type.{u1}} [_inst_1 : OrderedSemiring.{u1} α] [_inst_2 : DecidableRel.{succ u1} α (LT.lt.{u1} α (Preorder.toLT.{u1} α (PartialOrder.toPreorder.{u1} α (OrderedAddCommMonoid.toPartialOrder.{u1} α (OrderedSemiring.toOrderedAddCommMonoid.{u1} α _inst_1)))))] [_inst_3 : Nontrivial.{u1} α], Eq.{1} SignType (coeFn.{succ u1, succ u1} (OrderHom.{u1, 0} α SignType (PartialOrder.toPreorder.{u1} α (OrderedAddCommMonoid.toPartialOrder.{u1} α (OrderedSemiring.toOrderedAddCommMonoid.{u1} α _inst_1))) (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) (fun (_x : OrderHom.{u1, 0} α SignType (PartialOrder.toPreorder.{u1} α (OrderedAddCommMonoid.toPartialOrder.{u1} α (OrderedSemiring.toOrderedAddCommMonoid.{u1} α _inst_1))) (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) => α -> SignType) (OrderHom.hasCoeToFun.{u1, 0} α SignType (PartialOrder.toPreorder.{u1} α (OrderedAddCommMonoid.toPartialOrder.{u1} α (OrderedSemiring.toOrderedAddCommMonoid.{u1} α _inst_1))) (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) (SignType.sign.{u1} α (MulZeroClass.toHasZero.{u1} α (NonUnitalNonAssocSemiring.toMulZeroClass.{u1} α (NonAssocSemiring.toNonUnitalNonAssocSemiring.{u1} α (Semiring.toNonAssocSemiring.{u1} α (OrderedSemiring.toSemiring.{u1} α _inst_1))))) (PartialOrder.toPreorder.{u1} α (OrderedAddCommMonoid.toPartialOrder.{u1} α (OrderedSemiring.toOrderedAddCommMonoid.{u1} α _inst_1))) (fun (a : α) (b : α) => _inst_2 a b)) (OfNat.ofNat.{u1} α 1 (OfNat.mk.{u1} α 1 (One.one.{u1} α (AddMonoidWithOne.toOne.{u1} α (AddCommMonoidWithOne.toAddMonoidWithOne.{u1} α (NonAssocSemiring.toAddCommMonoidWithOne.{u1} α (Semiring.toNonAssocSemiring.{u1} α (OrderedSemiring.toSemiring.{u1} α _inst_1))))))))) (OfNat.ofNat.{0} SignType 1 (OfNat.mk.{0} SignType 1 (One.one.{0} SignType SignType.hasOne)))
 but is expected to have type
-  forall {α : Type.{u1}} [_inst_1 : OrderedSemiring.{u1} α] [_inst_2 : DecidableRel.{succ u1} α (fun (x._@.Mathlib.Data.Sign._hyg.5908 : α) (x._@.Mathlib.Data.Sign._hyg.5910 : α) => LT.lt.{u1} α (Preorder.toLT.{u1} α (PartialOrder.toPreorder.{u1} α (OrderedSemiring.toPartialOrder.{u1} α _inst_1))) x._@.Mathlib.Data.Sign._hyg.5908 x._@.Mathlib.Data.Sign._hyg.5910)] [_inst_3 : Nontrivial.{u1} α], Eq.{1} SignType (OrderHom.toFun.{u1, 0} α SignType (PartialOrder.toPreorder.{u1} α (OrderedSemiring.toPartialOrder.{u1} α _inst_1)) (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (DistribLattice.toLattice.{0} SignType (instDistribLattice.{0} SignType SignType.instLinearOrderSignType))))) (SignType.sign.{u1} α (MonoidWithZero.toZero.{u1} α (Semiring.toMonoidWithZero.{u1} α (OrderedSemiring.toSemiring.{u1} α _inst_1))) (PartialOrder.toPreorder.{u1} α (OrderedSemiring.toPartialOrder.{u1} α _inst_1)) (fun (a : α) (b : α) => _inst_2 a b)) (OfNat.ofNat.{u1} α 1 (One.toOfNat1.{u1} α (Semiring.toOne.{u1} α (OrderedSemiring.toSemiring.{u1} α _inst_1))))) (OfNat.ofNat.{0} SignType 1 (One.toOfNat1.{0} SignType SignType.instOneSignType))
+  forall {α : Type.{u1}} [_inst_1 : OrderedSemiring.{u1} α] [_inst_2 : DecidableRel.{succ u1} α (fun (x._@.Mathlib.Data.Sign._hyg.5946 : α) (x._@.Mathlib.Data.Sign._hyg.5948 : α) => LT.lt.{u1} α (Preorder.toLT.{u1} α (PartialOrder.toPreorder.{u1} α (OrderedSemiring.toPartialOrder.{u1} α _inst_1))) x._@.Mathlib.Data.Sign._hyg.5946 x._@.Mathlib.Data.Sign._hyg.5948)] [_inst_3 : Nontrivial.{u1} α], Eq.{1} SignType (OrderHom.toFun.{u1, 0} α SignType (PartialOrder.toPreorder.{u1} α (OrderedSemiring.toPartialOrder.{u1} α _inst_1)) (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (DistribLattice.toLattice.{0} SignType (instDistribLattice.{0} SignType SignType.instLinearOrderSignType))))) (SignType.sign.{u1} α (MonoidWithZero.toZero.{u1} α (Semiring.toMonoidWithZero.{u1} α (OrderedSemiring.toSemiring.{u1} α _inst_1))) (PartialOrder.toPreorder.{u1} α (OrderedSemiring.toPartialOrder.{u1} α _inst_1)) (fun (a : α) (b : α) => _inst_2 a b)) (OfNat.ofNat.{u1} α 1 (One.toOfNat1.{u1} α (Semiring.toOne.{u1} α (OrderedSemiring.toSemiring.{u1} α _inst_1))))) (OfNat.ofNat.{0} SignType 1 (One.toOfNat1.{0} SignType SignType.instOneSignType))
 Case conversion may be inaccurate. Consider using '#align sign_one sign_oneₓ'. -/
 @[simp]
 theorem sign_one : SignType.sign (1 : α) = 1 :=
@@ -552,7 +552,7 @@ variable [AddGroup α] [Preorder α] [DecidableRel ((· < ·) : α → α → Pr
 lean 3 declaration is
   forall {α : Type.{u1}} [_inst_1 : AddGroup.{u1} α] [_inst_2 : Preorder.{u1} α] [_inst_3 : DecidableRel.{succ u1} α (LT.lt.{u1} α (Preorder.toLT.{u1} α _inst_2))] [_inst_4 : CovariantClass.{u1, u1} α α (HAdd.hAdd.{u1, u1, u1} α α α (instHAdd.{u1} α (AddZeroClass.toHasAdd.{u1} α (AddMonoid.toAddZeroClass.{u1} α (SubNegMonoid.toAddMonoid.{u1} α (AddGroup.toSubNegMonoid.{u1} α _inst_1)))))) (LT.lt.{u1} α (Preorder.toLT.{u1} α _inst_2))] (a : α), Eq.{1} SignType (coeFn.{succ u1, succ u1} (OrderHom.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) (fun (_x : OrderHom.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) => α -> SignType) (OrderHom.hasCoeToFun.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) (SignType.sign.{u1} α (AddZeroClass.toHasZero.{u1} α (AddMonoid.toAddZeroClass.{u1} α (SubNegMonoid.toAddMonoid.{u1} α (AddGroup.toSubNegMonoid.{u1} α _inst_1)))) _inst_2 (fun (a : α) (b : α) => _inst_3 a b)) (Neg.neg.{u1} α (SubNegMonoid.toHasNeg.{u1} α (AddGroup.toSubNegMonoid.{u1} α _inst_1)) a)) (Neg.neg.{0} SignType SignType.hasNeg (coeFn.{succ u1, succ u1} (OrderHom.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) (fun (_x : OrderHom.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) => α -> SignType) (OrderHom.hasCoeToFun.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) (SignType.sign.{u1} α (AddZeroClass.toHasZero.{u1} α (AddMonoid.toAddZeroClass.{u1} α (SubNegMonoid.toAddMonoid.{u1} α (AddGroup.toSubNegMonoid.{u1} α _inst_1)))) _inst_2 (fun (a : α) (b : α) => _inst_3 a b)) a))
 but is expected to have type
-  forall {α : Type.{u1}} [_inst_1 : AddGroup.{u1} α] [_inst_2 : Preorder.{u1} α] [_inst_3 : DecidableRel.{succ u1} α (fun (x._@.Mathlib.Data.Sign._hyg.6429 : α) (x._@.Mathlib.Data.Sign._hyg.6431 : α) => LT.lt.{u1} α (Preorder.toLT.{u1} α _inst_2) x._@.Mathlib.Data.Sign._hyg.6429 x._@.Mathlib.Data.Sign._hyg.6431)] [_inst_4 : CovariantClass.{u1, u1} α α (fun (x._@.Mathlib.Data.Sign._hyg.6448 : α) (x._@.Mathlib.Data.Sign._hyg.6450 : α) => HAdd.hAdd.{u1, u1, u1} α α α (instHAdd.{u1} α (AddZeroClass.toAdd.{u1} α (AddMonoid.toAddZeroClass.{u1} α (SubNegMonoid.toAddMonoid.{u1} α (AddGroup.toSubNegMonoid.{u1} α _inst_1))))) x._@.Mathlib.Data.Sign._hyg.6448 x._@.Mathlib.Data.Sign._hyg.6450) (fun (x._@.Mathlib.Data.Sign._hyg.6463 : α) (x._@.Mathlib.Data.Sign._hyg.6465 : α) => LT.lt.{u1} α (Preorder.toLT.{u1} α _inst_2) x._@.Mathlib.Data.Sign._hyg.6463 x._@.Mathlib.Data.Sign._hyg.6465)] (a : α), Eq.{1} SignType (OrderHom.toFun.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (DistribLattice.toLattice.{0} SignType (instDistribLattice.{0} SignType SignType.instLinearOrderSignType))))) (SignType.sign.{u1} α (NegZeroClass.toZero.{u1} α (SubNegZeroMonoid.toNegZeroClass.{u1} α (SubtractionMonoid.toSubNegZeroMonoid.{u1} α (AddGroup.toSubtractionMonoid.{u1} α _inst_1)))) _inst_2 (fun (a : α) (b : α) => _inst_3 a b)) (Neg.neg.{u1} α (NegZeroClass.toNeg.{u1} α (SubNegZeroMonoid.toNegZeroClass.{u1} α (SubtractionMonoid.toSubNegZeroMonoid.{u1} α (AddGroup.toSubtractionMonoid.{u1} α _inst_1)))) a)) (Neg.neg.{0} SignType SignType.instNegSignType (OrderHom.toFun.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (DistribLattice.toLattice.{0} SignType (instDistribLattice.{0} SignType SignType.instLinearOrderSignType))))) (SignType.sign.{u1} α (NegZeroClass.toZero.{u1} α (SubNegZeroMonoid.toNegZeroClass.{u1} α (SubtractionMonoid.toSubNegZeroMonoid.{u1} α (AddGroup.toSubtractionMonoid.{u1} α _inst_1)))) _inst_2 (fun (a : α) (b : α) => _inst_3 a b)) a))
+  forall {α : Type.{u1}} [_inst_1 : AddGroup.{u1} α] [_inst_2 : Preorder.{u1} α] [_inst_3 : DecidableRel.{succ u1} α (fun (x._@.Mathlib.Data.Sign._hyg.6467 : α) (x._@.Mathlib.Data.Sign._hyg.6469 : α) => LT.lt.{u1} α (Preorder.toLT.{u1} α _inst_2) x._@.Mathlib.Data.Sign._hyg.6467 x._@.Mathlib.Data.Sign._hyg.6469)] [_inst_4 : CovariantClass.{u1, u1} α α (fun (x._@.Mathlib.Data.Sign._hyg.6486 : α) (x._@.Mathlib.Data.Sign._hyg.6488 : α) => HAdd.hAdd.{u1, u1, u1} α α α (instHAdd.{u1} α (AddZeroClass.toAdd.{u1} α (AddMonoid.toAddZeroClass.{u1} α (SubNegMonoid.toAddMonoid.{u1} α (AddGroup.toSubNegMonoid.{u1} α _inst_1))))) x._@.Mathlib.Data.Sign._hyg.6486 x._@.Mathlib.Data.Sign._hyg.6488) (fun (x._@.Mathlib.Data.Sign._hyg.6501 : α) (x._@.Mathlib.Data.Sign._hyg.6503 : α) => LT.lt.{u1} α (Preorder.toLT.{u1} α _inst_2) x._@.Mathlib.Data.Sign._hyg.6501 x._@.Mathlib.Data.Sign._hyg.6503)] (a : α), Eq.{1} SignType (OrderHom.toFun.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (DistribLattice.toLattice.{0} SignType (instDistribLattice.{0} SignType SignType.instLinearOrderSignType))))) (SignType.sign.{u1} α (NegZeroClass.toZero.{u1} α (SubNegZeroMonoid.toNegZeroClass.{u1} α (SubtractionMonoid.toSubNegZeroMonoid.{u1} α (AddGroup.toSubtractionMonoid.{u1} α _inst_1)))) _inst_2 (fun (a : α) (b : α) => _inst_3 a b)) (Neg.neg.{u1} α (NegZeroClass.toNeg.{u1} α (SubNegZeroMonoid.toNegZeroClass.{u1} α (SubtractionMonoid.toSubNegZeroMonoid.{u1} α (AddGroup.toSubtractionMonoid.{u1} α _inst_1)))) a)) (Neg.neg.{0} SignType SignType.instNegSignType (OrderHom.toFun.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (DistribLattice.toLattice.{0} SignType (instDistribLattice.{0} SignType SignType.instLinearOrderSignType))))) (SignType.sign.{u1} α (NegZeroClass.toZero.{u1} α (SubNegZeroMonoid.toNegZeroClass.{u1} α (SubtractionMonoid.toSubNegZeroMonoid.{u1} α (AddGroup.toSubtractionMonoid.{u1} α _inst_1)))) _inst_2 (fun (a : α) (b : α) => _inst_3 a b)) a))
 Case conversion may be inaccurate. Consider using '#align left.sign_neg Left.sign_negₓ'. -/
 theorem Left.sign_neg [CovariantClass α α (· + ·) (· < ·)] (a : α) :
     SignType.sign (-a) = -SignType.sign a :=
@@ -569,7 +569,7 @@ theorem Left.sign_neg [CovariantClass α α (· + ·) (· < ·)] (a : α) :
 lean 3 declaration is
   forall {α : Type.{u1}} [_inst_1 : AddGroup.{u1} α] [_inst_2 : Preorder.{u1} α] [_inst_3 : DecidableRel.{succ u1} α (LT.lt.{u1} α (Preorder.toLT.{u1} α _inst_2))] [_inst_4 : CovariantClass.{u1, u1} α α (Function.swap.{succ u1, succ u1, succ u1} α α (fun (ᾰ : α) (ᾰ : α) => α) (HAdd.hAdd.{u1, u1, u1} α α α (instHAdd.{u1} α (AddZeroClass.toHasAdd.{u1} α (AddMonoid.toAddZeroClass.{u1} α (SubNegMonoid.toAddMonoid.{u1} α (AddGroup.toSubNegMonoid.{u1} α _inst_1))))))) (LT.lt.{u1} α (Preorder.toLT.{u1} α _inst_2))] (a : α), Eq.{1} SignType (coeFn.{succ u1, succ u1} (OrderHom.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) (fun (_x : OrderHom.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) => α -> SignType) (OrderHom.hasCoeToFun.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) (SignType.sign.{u1} α (AddZeroClass.toHasZero.{u1} α (AddMonoid.toAddZeroClass.{u1} α (SubNegMonoid.toAddMonoid.{u1} α (AddGroup.toSubNegMonoid.{u1} α _inst_1)))) _inst_2 (fun (a : α) (b : α) => _inst_3 a b)) (Neg.neg.{u1} α (SubNegMonoid.toHasNeg.{u1} α (AddGroup.toSubNegMonoid.{u1} α _inst_1)) a)) (Neg.neg.{0} SignType SignType.hasNeg (coeFn.{succ u1, succ u1} (OrderHom.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) (fun (_x : OrderHom.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) => α -> SignType) (OrderHom.hasCoeToFun.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) (SignType.sign.{u1} α (AddZeroClass.toHasZero.{u1} α (AddMonoid.toAddZeroClass.{u1} α (SubNegMonoid.toAddMonoid.{u1} α (AddGroup.toSubNegMonoid.{u1} α _inst_1)))) _inst_2 (fun (a : α) (b : α) => _inst_3 a b)) a))
 but is expected to have type
-  forall {α : Type.{u1}} [_inst_1 : AddGroup.{u1} α] [_inst_2 : Preorder.{u1} α] [_inst_3 : DecidableRel.{succ u1} α (fun (x._@.Mathlib.Data.Sign._hyg.6549 : α) (x._@.Mathlib.Data.Sign._hyg.6551 : α) => LT.lt.{u1} α (Preorder.toLT.{u1} α _inst_2) x._@.Mathlib.Data.Sign._hyg.6549 x._@.Mathlib.Data.Sign._hyg.6551)] [_inst_4 : CovariantClass.{u1, u1} α α (Function.swap.{succ u1, succ u1, succ u1} α α (fun (ᾰ : α) (ᾰ : α) => α) (fun (x._@.Mathlib.Data.Sign._hyg.6571 : α) (x._@.Mathlib.Data.Sign._hyg.6573 : α) => HAdd.hAdd.{u1, u1, u1} α α α (instHAdd.{u1} α (AddZeroClass.toAdd.{u1} α (AddMonoid.toAddZeroClass.{u1} α (SubNegMonoid.toAddMonoid.{u1} α (AddGroup.toSubNegMonoid.{u1} α _inst_1))))) x._@.Mathlib.Data.Sign._hyg.6571 x._@.Mathlib.Data.Sign._hyg.6573)) (fun (x._@.Mathlib.Data.Sign._hyg.6586 : α) (x._@.Mathlib.Data.Sign._hyg.6588 : α) => LT.lt.{u1} α (Preorder.toLT.{u1} α _inst_2) x._@.Mathlib.Data.Sign._hyg.6586 x._@.Mathlib.Data.Sign._hyg.6588)] (a : α), Eq.{1} SignType (OrderHom.toFun.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (DistribLattice.toLattice.{0} SignType (instDistribLattice.{0} SignType SignType.instLinearOrderSignType))))) (SignType.sign.{u1} α (NegZeroClass.toZero.{u1} α (SubNegZeroMonoid.toNegZeroClass.{u1} α (SubtractionMonoid.toSubNegZeroMonoid.{u1} α (AddGroup.toSubtractionMonoid.{u1} α _inst_1)))) _inst_2 (fun (a : α) (b : α) => _inst_3 a b)) (Neg.neg.{u1} α (NegZeroClass.toNeg.{u1} α (SubNegZeroMonoid.toNegZeroClass.{u1} α (SubtractionMonoid.toSubNegZeroMonoid.{u1} α (AddGroup.toSubtractionMonoid.{u1} α _inst_1)))) a)) (Neg.neg.{0} SignType SignType.instNegSignType (OrderHom.toFun.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (DistribLattice.toLattice.{0} SignType (instDistribLattice.{0} SignType SignType.instLinearOrderSignType))))) (SignType.sign.{u1} α (NegZeroClass.toZero.{u1} α (SubNegZeroMonoid.toNegZeroClass.{u1} α (SubtractionMonoid.toSubNegZeroMonoid.{u1} α (AddGroup.toSubtractionMonoid.{u1} α _inst_1)))) _inst_2 (fun (a : α) (b : α) => _inst_3 a b)) a))
+  forall {α : Type.{u1}} [_inst_1 : AddGroup.{u1} α] [_inst_2 : Preorder.{u1} α] [_inst_3 : DecidableRel.{succ u1} α (fun (x._@.Mathlib.Data.Sign._hyg.6587 : α) (x._@.Mathlib.Data.Sign._hyg.6589 : α) => LT.lt.{u1} α (Preorder.toLT.{u1} α _inst_2) x._@.Mathlib.Data.Sign._hyg.6587 x._@.Mathlib.Data.Sign._hyg.6589)] [_inst_4 : CovariantClass.{u1, u1} α α (Function.swap.{succ u1, succ u1, succ u1} α α (fun (ᾰ : α) (ᾰ : α) => α) (fun (x._@.Mathlib.Data.Sign._hyg.6609 : α) (x._@.Mathlib.Data.Sign._hyg.6611 : α) => HAdd.hAdd.{u1, u1, u1} α α α (instHAdd.{u1} α (AddZeroClass.toAdd.{u1} α (AddMonoid.toAddZeroClass.{u1} α (SubNegMonoid.toAddMonoid.{u1} α (AddGroup.toSubNegMonoid.{u1} α _inst_1))))) x._@.Mathlib.Data.Sign._hyg.6609 x._@.Mathlib.Data.Sign._hyg.6611)) (fun (x._@.Mathlib.Data.Sign._hyg.6624 : α) (x._@.Mathlib.Data.Sign._hyg.6626 : α) => LT.lt.{u1} α (Preorder.toLT.{u1} α _inst_2) x._@.Mathlib.Data.Sign._hyg.6624 x._@.Mathlib.Data.Sign._hyg.6626)] (a : α), Eq.{1} SignType (OrderHom.toFun.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (DistribLattice.toLattice.{0} SignType (instDistribLattice.{0} SignType SignType.instLinearOrderSignType))))) (SignType.sign.{u1} α (NegZeroClass.toZero.{u1} α (SubNegZeroMonoid.toNegZeroClass.{u1} α (SubtractionMonoid.toSubNegZeroMonoid.{u1} α (AddGroup.toSubtractionMonoid.{u1} α _inst_1)))) _inst_2 (fun (a : α) (b : α) => _inst_3 a b)) (Neg.neg.{u1} α (NegZeroClass.toNeg.{u1} α (SubNegZeroMonoid.toNegZeroClass.{u1} α (SubtractionMonoid.toSubNegZeroMonoid.{u1} α (AddGroup.toSubtractionMonoid.{u1} α _inst_1)))) a)) (Neg.neg.{0} SignType SignType.instNegSignType (OrderHom.toFun.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (DistribLattice.toLattice.{0} SignType (instDistribLattice.{0} SignType SignType.instLinearOrderSignType))))) (SignType.sign.{u1} α (NegZeroClass.toZero.{u1} α (SubNegZeroMonoid.toNegZeroClass.{u1} α (SubtractionMonoid.toSubNegZeroMonoid.{u1} α (AddGroup.toSubtractionMonoid.{u1} α _inst_1)))) _inst_2 (fun (a : α) (b : α) => _inst_3 a b)) a))
 Case conversion may be inaccurate. Consider using '#align right.sign_neg Right.sign_negₓ'. -/
 theorem Right.sign_neg [CovariantClass α α (Function.swap (· + ·)) (· < ·)] (a : α) :
     SignType.sign (-a) = -SignType.sign a :=

mathlib commit https://github.com/leanprover-community/mathlib/commit/57e09a1296bfb4330ddf6624f1028ba186117d82

@@ -368,7 +368,7 @@ variable [Zero α] [Preorder α] [DecidableRel ((· < ·) : α → α → Prop)]
 lean 3 declaration is
   forall {α : Type.{u1}} [_inst_1 : Zero.{u1} α] [_inst_2 : Preorder.{u1} α] [_inst_3 : DecidableRel.{succ u1} α (LT.lt.{u1} α (Preorder.toLT.{u1} α _inst_2))], OrderHom.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))
 but is expected to have type
-  forall {α : Type.{u1}} [_inst_1 : Zero.{u1} α] [_inst_2 : Preorder.{u1} α] [_inst_3 : DecidableRel.{succ u1} α (fun (x._@.Mathlib.Data.Sign._hyg.5020 : α) (x._@.Mathlib.Data.Sign._hyg.5022 : α) => LT.lt.{u1} α (Preorder.toLT.{u1} α _inst_2) x._@.Mathlib.Data.Sign._hyg.5020 x._@.Mathlib.Data.Sign._hyg.5022)], OrderHom.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (DistribLattice.toLattice.{0} SignType (instDistribLattice.{0} SignType SignType.instLinearOrderSignType)))))
+  forall {α : Type.{u1}} [_inst_1 : Zero.{u1} α] [_inst_2 : Preorder.{u1} α] [_inst_3 : DecidableRel.{succ u1} α (fun (x._@.Mathlib.Data.Sign._hyg.4949 : α) (x._@.Mathlib.Data.Sign._hyg.4951 : α) => LT.lt.{u1} α (Preorder.toLT.{u1} α _inst_2) x._@.Mathlib.Data.Sign._hyg.4949 x._@.Mathlib.Data.Sign._hyg.4951)], OrderHom.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (DistribLattice.toLattice.{0} SignType (instDistribLattice.{0} SignType SignType.instLinearOrderSignType)))))
 Case conversion may be inaccurate. Consider using '#align sign SignType.signₓ'. -/
 /-- The sign of an element is 1 if it's positive, -1 if negative, 0 otherwise. -/
 def SignType.sign : α →o SignType :=
@@ -483,7 +483,7 @@ variable [OrderedSemiring α] [DecidableRel ((· < ·) : α → α → Prop)] [N
 lean 3 declaration is
   forall {α : Type.{u1}} [_inst_1 : OrderedSemiring.{u1} α] [_inst_2 : DecidableRel.{succ u1} α (LT.lt.{u1} α (Preorder.toLT.{u1} α (PartialOrder.toPreorder.{u1} α (OrderedAddCommMonoid.toPartialOrder.{u1} α (OrderedSemiring.toOrderedAddCommMonoid.{u1} α _inst_1)))))] [_inst_3 : Nontrivial.{u1} α], Eq.{1} SignType (coeFn.{succ u1, succ u1} (OrderHom.{u1, 0} α SignType (PartialOrder.toPreorder.{u1} α (OrderedAddCommMonoid.toPartialOrder.{u1} α (OrderedSemiring.toOrderedAddCommMonoid.{u1} α _inst_1))) (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) (fun (_x : OrderHom.{u1, 0} α SignType (PartialOrder.toPreorder.{u1} α (OrderedAddCommMonoid.toPartialOrder.{u1} α (OrderedSemiring.toOrderedAddCommMonoid.{u1} α _inst_1))) (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) => α -> SignType) (OrderHom.hasCoeToFun.{u1, 0} α SignType (PartialOrder.toPreorder.{u1} α (OrderedAddCommMonoid.toPartialOrder.{u1} α (OrderedSemiring.toOrderedAddCommMonoid.{u1} α _inst_1))) (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) (SignType.sign.{u1} α (MulZeroClass.toHasZero.{u1} α (NonUnitalNonAssocSemiring.toMulZeroClass.{u1} α (NonAssocSemiring.toNonUnitalNonAssocSemiring.{u1} α (Semiring.toNonAssocSemiring.{u1} α (OrderedSemiring.toSemiring.{u1} α _inst_1))))) (PartialOrder.toPreorder.{u1} α (OrderedAddCommMonoid.toPartialOrder.{u1} α (OrderedSemiring.toOrderedAddCommMonoid.{u1} α _inst_1))) (fun (a : α) (b : α) => _inst_2 a b)) (OfNat.ofNat.{u1} α 1 (OfNat.mk.{u1} α 1 (One.one.{u1} α (AddMonoidWithOne.toOne.{u1} α (AddCommMonoidWithOne.toAddMonoidWithOne.{u1} α (NonAssocSemiring.toAddCommMonoidWithOne.{u1} α (Semiring.toNonAssocSemiring.{u1} α (OrderedSemiring.toSemiring.{u1} α _inst_1))))))))) (OfNat.ofNat.{0} SignType 1 (OfNat.mk.{0} SignType 1 (One.one.{0} SignType SignType.hasOne)))
 but is expected to have type
-  forall {α : Type.{u1}} [_inst_1 : OrderedSemiring.{u1} α] [_inst_2 : DecidableRel.{succ u1} α (fun (x._@.Mathlib.Data.Sign._hyg.5979 : α) (x._@.Mathlib.Data.Sign._hyg.5981 : α) => LT.lt.{u1} α (Preorder.toLT.{u1} α (PartialOrder.toPreorder.{u1} α (OrderedSemiring.toPartialOrder.{u1} α _inst_1))) x._@.Mathlib.Data.Sign._hyg.5979 x._@.Mathlib.Data.Sign._hyg.5981)] [_inst_3 : Nontrivial.{u1} α], Eq.{1} SignType (OrderHom.toFun.{u1, 0} α SignType (PartialOrder.toPreorder.{u1} α (OrderedSemiring.toPartialOrder.{u1} α _inst_1)) (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (DistribLattice.toLattice.{0} SignType (instDistribLattice.{0} SignType SignType.instLinearOrderSignType))))) (SignType.sign.{u1} α (MonoidWithZero.toZero.{u1} α (Semiring.toMonoidWithZero.{u1} α (OrderedSemiring.toSemiring.{u1} α _inst_1))) (PartialOrder.toPreorder.{u1} α (OrderedSemiring.toPartialOrder.{u1} α _inst_1)) (fun (a : α) (b : α) => _inst_2 a b)) (OfNat.ofNat.{u1} α 1 (One.toOfNat1.{u1} α (Semiring.toOne.{u1} α (OrderedSemiring.toSemiring.{u1} α _inst_1))))) (OfNat.ofNat.{0} SignType 1 (One.toOfNat1.{0} SignType SignType.instOneSignType))
+  forall {α : Type.{u1}} [_inst_1 : OrderedSemiring.{u1} α] [_inst_2 : DecidableRel.{succ u1} α (fun (x._@.Mathlib.Data.Sign._hyg.5908 : α) (x._@.Mathlib.Data.Sign._hyg.5910 : α) => LT.lt.{u1} α (Preorder.toLT.{u1} α (PartialOrder.toPreorder.{u1} α (OrderedSemiring.toPartialOrder.{u1} α _inst_1))) x._@.Mathlib.Data.Sign._hyg.5908 x._@.Mathlib.Data.Sign._hyg.5910)] [_inst_3 : Nontrivial.{u1} α], Eq.{1} SignType (OrderHom.toFun.{u1, 0} α SignType (PartialOrder.toPreorder.{u1} α (OrderedSemiring.toPartialOrder.{u1} α _inst_1)) (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (DistribLattice.toLattice.{0} SignType (instDistribLattice.{0} SignType SignType.instLinearOrderSignType))))) (SignType.sign.{u1} α (MonoidWithZero.toZero.{u1} α (Semiring.toMonoidWithZero.{u1} α (OrderedSemiring.toSemiring.{u1} α _inst_1))) (PartialOrder.toPreorder.{u1} α (OrderedSemiring.toPartialOrder.{u1} α _inst_1)) (fun (a : α) (b : α) => _inst_2 a b)) (OfNat.ofNat.{u1} α 1 (One.toOfNat1.{u1} α (Semiring.toOne.{u1} α (OrderedSemiring.toSemiring.{u1} α _inst_1))))) (OfNat.ofNat.{0} SignType 1 (One.toOfNat1.{0} SignType SignType.instOneSignType))
 Case conversion may be inaccurate. Consider using '#align sign_one sign_oneₓ'. -/
 @[simp]
 theorem sign_one : SignType.sign (1 : α) = 1 :=
@@ -552,7 +552,7 @@ variable [AddGroup α] [Preorder α] [DecidableRel ((· < ·) : α → α → Pr
 lean 3 declaration is
   forall {α : Type.{u1}} [_inst_1 : AddGroup.{u1} α] [_inst_2 : Preorder.{u1} α] [_inst_3 : DecidableRel.{succ u1} α (LT.lt.{u1} α (Preorder.toLT.{u1} α _inst_2))] [_inst_4 : CovariantClass.{u1, u1} α α (HAdd.hAdd.{u1, u1, u1} α α α (instHAdd.{u1} α (AddZeroClass.toHasAdd.{u1} α (AddMonoid.toAddZeroClass.{u1} α (SubNegMonoid.toAddMonoid.{u1} α (AddGroup.toSubNegMonoid.{u1} α _inst_1)))))) (LT.lt.{u1} α (Preorder.toLT.{u1} α _inst_2))] (a : α), Eq.{1} SignType (coeFn.{succ u1, succ u1} (OrderHom.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) (fun (_x : OrderHom.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) => α -> SignType) (OrderHom.hasCoeToFun.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) (SignType.sign.{u1} α (AddZeroClass.toHasZero.{u1} α (AddMonoid.toAddZeroClass.{u1} α (SubNegMonoid.toAddMonoid.{u1} α (AddGroup.toSubNegMonoid.{u1} α _inst_1)))) _inst_2 (fun (a : α) (b : α) => _inst_3 a b)) (Neg.neg.{u1} α (SubNegMonoid.toHasNeg.{u1} α (AddGroup.toSubNegMonoid.{u1} α _inst_1)) a)) (Neg.neg.{0} SignType SignType.hasNeg (coeFn.{succ u1, succ u1} (OrderHom.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) (fun (_x : OrderHom.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) => α -> SignType) (OrderHom.hasCoeToFun.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) (SignType.sign.{u1} α (AddZeroClass.toHasZero.{u1} α (AddMonoid.toAddZeroClass.{u1} α (SubNegMonoid.toAddMonoid.{u1} α (AddGroup.toSubNegMonoid.{u1} α _inst_1)))) _inst_2 (fun (a : α) (b : α) => _inst_3 a b)) a))
 but is expected to have type
-  forall {α : Type.{u1}} [_inst_1 : AddGroup.{u1} α] [_inst_2 : Preorder.{u1} α] [_inst_3 : DecidableRel.{succ u1} α (fun (x._@.Mathlib.Data.Sign._hyg.6500 : α) (x._@.Mathlib.Data.Sign._hyg.6502 : α) => LT.lt.{u1} α (Preorder.toLT.{u1} α _inst_2) x._@.Mathlib.Data.Sign._hyg.6500 x._@.Mathlib.Data.Sign._hyg.6502)] [_inst_4 : CovariantClass.{u1, u1} α α (fun (x._@.Mathlib.Data.Sign._hyg.6519 : α) (x._@.Mathlib.Data.Sign._hyg.6521 : α) => HAdd.hAdd.{u1, u1, u1} α α α (instHAdd.{u1} α (AddZeroClass.toAdd.{u1} α (AddMonoid.toAddZeroClass.{u1} α (SubNegMonoid.toAddMonoid.{u1} α (AddGroup.toSubNegMonoid.{u1} α _inst_1))))) x._@.Mathlib.Data.Sign._hyg.6519 x._@.Mathlib.Data.Sign._hyg.6521) (fun (x._@.Mathlib.Data.Sign._hyg.6534 : α) (x._@.Mathlib.Data.Sign._hyg.6536 : α) => LT.lt.{u1} α (Preorder.toLT.{u1} α _inst_2) x._@.Mathlib.Data.Sign._hyg.6534 x._@.Mathlib.Data.Sign._hyg.6536)] (a : α), Eq.{1} SignType (OrderHom.toFun.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (DistribLattice.toLattice.{0} SignType (instDistribLattice.{0} SignType SignType.instLinearOrderSignType))))) (SignType.sign.{u1} α (NegZeroClass.toZero.{u1} α (SubNegZeroMonoid.toNegZeroClass.{u1} α (SubtractionMonoid.toSubNegZeroMonoid.{u1} α (AddGroup.toSubtractionMonoid.{u1} α _inst_1)))) _inst_2 (fun (a : α) (b : α) => _inst_3 a b)) (Neg.neg.{u1} α (NegZeroClass.toNeg.{u1} α (SubNegZeroMonoid.toNegZeroClass.{u1} α (SubtractionMonoid.toSubNegZeroMonoid.{u1} α (AddGroup.toSubtractionMonoid.{u1} α _inst_1)))) a)) (Neg.neg.{0} SignType SignType.instNegSignType (OrderHom.toFun.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (DistribLattice.toLattice.{0} SignType (instDistribLattice.{0} SignType SignType.instLinearOrderSignType))))) (SignType.sign.{u1} α (NegZeroClass.toZero.{u1} α (SubNegZeroMonoid.toNegZeroClass.{u1} α (SubtractionMonoid.toSubNegZeroMonoid.{u1} α (AddGroup.toSubtractionMonoid.{u1} α _inst_1)))) _inst_2 (fun (a : α) (b : α) => _inst_3 a b)) a))
+  forall {α : Type.{u1}} [_inst_1 : AddGroup.{u1} α] [_inst_2 : Preorder.{u1} α] [_inst_3 : DecidableRel.{succ u1} α (fun (x._@.Mathlib.Data.Sign._hyg.6429 : α) (x._@.Mathlib.Data.Sign._hyg.6431 : α) => LT.lt.{u1} α (Preorder.toLT.{u1} α _inst_2) x._@.Mathlib.Data.Sign._hyg.6429 x._@.Mathlib.Data.Sign._hyg.6431)] [_inst_4 : CovariantClass.{u1, u1} α α (fun (x._@.Mathlib.Data.Sign._hyg.6448 : α) (x._@.Mathlib.Data.Sign._hyg.6450 : α) => HAdd.hAdd.{u1, u1, u1} α α α (instHAdd.{u1} α (AddZeroClass.toAdd.{u1} α (AddMonoid.toAddZeroClass.{u1} α (SubNegMonoid.toAddMonoid.{u1} α (AddGroup.toSubNegMonoid.{u1} α _inst_1))))) x._@.Mathlib.Data.Sign._hyg.6448 x._@.Mathlib.Data.Sign._hyg.6450) (fun (x._@.Mathlib.Data.Sign._hyg.6463 : α) (x._@.Mathlib.Data.Sign._hyg.6465 : α) => LT.lt.{u1} α (Preorder.toLT.{u1} α _inst_2) x._@.Mathlib.Data.Sign._hyg.6463 x._@.Mathlib.Data.Sign._hyg.6465)] (a : α), Eq.{1} SignType (OrderHom.toFun.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (DistribLattice.toLattice.{0} SignType (instDistribLattice.{0} SignType SignType.instLinearOrderSignType))))) (SignType.sign.{u1} α (NegZeroClass.toZero.{u1} α (SubNegZeroMonoid.toNegZeroClass.{u1} α (SubtractionMonoid.toSubNegZeroMonoid.{u1} α (AddGroup.toSubtractionMonoid.{u1} α _inst_1)))) _inst_2 (fun (a : α) (b : α) => _inst_3 a b)) (Neg.neg.{u1} α (NegZeroClass.toNeg.{u1} α (SubNegZeroMonoid.toNegZeroClass.{u1} α (SubtractionMonoid.toSubNegZeroMonoid.{u1} α (AddGroup.toSubtractionMonoid.{u1} α _inst_1)))) a)) (Neg.neg.{0} SignType SignType.instNegSignType (OrderHom.toFun.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (DistribLattice.toLattice.{0} SignType (instDistribLattice.{0} SignType SignType.instLinearOrderSignType))))) (SignType.sign.{u1} α (NegZeroClass.toZero.{u1} α (SubNegZeroMonoid.toNegZeroClass.{u1} α (SubtractionMonoid.toSubNegZeroMonoid.{u1} α (AddGroup.toSubtractionMonoid.{u1} α _inst_1)))) _inst_2 (fun (a : α) (b : α) => _inst_3 a b)) a))
 Case conversion may be inaccurate. Consider using '#align left.sign_neg Left.sign_negₓ'. -/
 theorem Left.sign_neg [CovariantClass α α (· + ·) (· < ·)] (a : α) :
     SignType.sign (-a) = -SignType.sign a :=
@@ -569,7 +569,7 @@ theorem Left.sign_neg [CovariantClass α α (· + ·) (· < ·)] (a : α) :
 lean 3 declaration is
   forall {α : Type.{u1}} [_inst_1 : AddGroup.{u1} α] [_inst_2 : Preorder.{u1} α] [_inst_3 : DecidableRel.{succ u1} α (LT.lt.{u1} α (Preorder.toLT.{u1} α _inst_2))] [_inst_4 : CovariantClass.{u1, u1} α α (Function.swap.{succ u1, succ u1, succ u1} α α (fun (ᾰ : α) (ᾰ : α) => α) (HAdd.hAdd.{u1, u1, u1} α α α (instHAdd.{u1} α (AddZeroClass.toHasAdd.{u1} α (AddMonoid.toAddZeroClass.{u1} α (SubNegMonoid.toAddMonoid.{u1} α (AddGroup.toSubNegMonoid.{u1} α _inst_1))))))) (LT.lt.{u1} α (Preorder.toLT.{u1} α _inst_2))] (a : α), Eq.{1} SignType (coeFn.{succ u1, succ u1} (OrderHom.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) (fun (_x : OrderHom.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) => α -> SignType) (OrderHom.hasCoeToFun.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) (SignType.sign.{u1} α (AddZeroClass.toHasZero.{u1} α (AddMonoid.toAddZeroClass.{u1} α (SubNegMonoid.toAddMonoid.{u1} α (AddGroup.toSubNegMonoid.{u1} α _inst_1)))) _inst_2 (fun (a : α) (b : α) => _inst_3 a b)) (Neg.neg.{u1} α (SubNegMonoid.toHasNeg.{u1} α (AddGroup.toSubNegMonoid.{u1} α _inst_1)) a)) (Neg.neg.{0} SignType SignType.hasNeg (coeFn.{succ u1, succ u1} (OrderHom.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) (fun (_x : OrderHom.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) => α -> SignType) (OrderHom.hasCoeToFun.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) (SignType.sign.{u1} α (AddZeroClass.toHasZero.{u1} α (AddMonoid.toAddZeroClass.{u1} α (SubNegMonoid.toAddMonoid.{u1} α (AddGroup.toSubNegMonoid.{u1} α _inst_1)))) _inst_2 (fun (a : α) (b : α) => _inst_3 a b)) a))
 but is expected to have type
-  forall {α : Type.{u1}} [_inst_1 : AddGroup.{u1} α] [_inst_2 : Preorder.{u1} α] [_inst_3 : DecidableRel.{succ u1} α (fun (x._@.Mathlib.Data.Sign._hyg.6620 : α) (x._@.Mathlib.Data.Sign._hyg.6622 : α) => LT.lt.{u1} α (Preorder.toLT.{u1} α _inst_2) x._@.Mathlib.Data.Sign._hyg.6620 x._@.Mathlib.Data.Sign._hyg.6622)] [_inst_4 : CovariantClass.{u1, u1} α α (Function.swap.{succ u1, succ u1, succ u1} α α (fun (ᾰ : α) (ᾰ : α) => α) (fun (x._@.Mathlib.Data.Sign._hyg.6642 : α) (x._@.Mathlib.Data.Sign._hyg.6644 : α) => HAdd.hAdd.{u1, u1, u1} α α α (instHAdd.{u1} α (AddZeroClass.toAdd.{u1} α (AddMonoid.toAddZeroClass.{u1} α (SubNegMonoid.toAddMonoid.{u1} α (AddGroup.toSubNegMonoid.{u1} α _inst_1))))) x._@.Mathlib.Data.Sign._hyg.6642 x._@.Mathlib.Data.Sign._hyg.6644)) (fun (x._@.Mathlib.Data.Sign._hyg.6657 : α) (x._@.Mathlib.Data.Sign._hyg.6659 : α) => LT.lt.{u1} α (Preorder.toLT.{u1} α _inst_2) x._@.Mathlib.Data.Sign._hyg.6657 x._@.Mathlib.Data.Sign._hyg.6659)] (a : α), Eq.{1} SignType (OrderHom.toFun.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (DistribLattice.toLattice.{0} SignType (instDistribLattice.{0} SignType SignType.instLinearOrderSignType))))) (SignType.sign.{u1} α (NegZeroClass.toZero.{u1} α (SubNegZeroMonoid.toNegZeroClass.{u1} α (SubtractionMonoid.toSubNegZeroMonoid.{u1} α (AddGroup.toSubtractionMonoid.{u1} α _inst_1)))) _inst_2 (fun (a : α) (b : α) => _inst_3 a b)) (Neg.neg.{u1} α (NegZeroClass.toNeg.{u1} α (SubNegZeroMonoid.toNegZeroClass.{u1} α (SubtractionMonoid.toSubNegZeroMonoid.{u1} α (AddGroup.toSubtractionMonoid.{u1} α _inst_1)))) a)) (Neg.neg.{0} SignType SignType.instNegSignType (OrderHom.toFun.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (DistribLattice.toLattice.{0} SignType (instDistribLattice.{0} SignType SignType.instLinearOrderSignType))))) (SignType.sign.{u1} α (NegZeroClass.toZero.{u1} α (SubNegZeroMonoid.toNegZeroClass.{u1} α (SubtractionMonoid.toSubNegZeroMonoid.{u1} α (AddGroup.toSubtractionMonoid.{u1} α _inst_1)))) _inst_2 (fun (a : α) (b : α) => _inst_3 a b)) a))
+  forall {α : Type.{u1}} [_inst_1 : AddGroup.{u1} α] [_inst_2 : Preorder.{u1} α] [_inst_3 : DecidableRel.{succ u1} α (fun (x._@.Mathlib.Data.Sign._hyg.6549 : α) (x._@.Mathlib.Data.Sign._hyg.6551 : α) => LT.lt.{u1} α (Preorder.toLT.{u1} α _inst_2) x._@.Mathlib.Data.Sign._hyg.6549 x._@.Mathlib.Data.Sign._hyg.6551)] [_inst_4 : CovariantClass.{u1, u1} α α (Function.swap.{succ u1, succ u1, succ u1} α α (fun (ᾰ : α) (ᾰ : α) => α) (fun (x._@.Mathlib.Data.Sign._hyg.6571 : α) (x._@.Mathlib.Data.Sign._hyg.6573 : α) => HAdd.hAdd.{u1, u1, u1} α α α (instHAdd.{u1} α (AddZeroClass.toAdd.{u1} α (AddMonoid.toAddZeroClass.{u1} α (SubNegMonoid.toAddMonoid.{u1} α (AddGroup.toSubNegMonoid.{u1} α _inst_1))))) x._@.Mathlib.Data.Sign._hyg.6571 x._@.Mathlib.Data.Sign._hyg.6573)) (fun (x._@.Mathlib.Data.Sign._hyg.6586 : α) (x._@.Mathlib.Data.Sign._hyg.6588 : α) => LT.lt.{u1} α (Preorder.toLT.{u1} α _inst_2) x._@.Mathlib.Data.Sign._hyg.6586 x._@.Mathlib.Data.Sign._hyg.6588)] (a : α), Eq.{1} SignType (OrderHom.toFun.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (DistribLattice.toLattice.{0} SignType (instDistribLattice.{0} SignType SignType.instLinearOrderSignType))))) (SignType.sign.{u1} α (NegZeroClass.toZero.{u1} α (SubNegZeroMonoid.toNegZeroClass.{u1} α (SubtractionMonoid.toSubNegZeroMonoid.{u1} α (AddGroup.toSubtractionMonoid.{u1} α _inst_1)))) _inst_2 (fun (a : α) (b : α) => _inst_3 a b)) (Neg.neg.{u1} α (NegZeroClass.toNeg.{u1} α (SubNegZeroMonoid.toNegZeroClass.{u1} α (SubtractionMonoid.toSubNegZeroMonoid.{u1} α (AddGroup.toSubtractionMonoid.{u1} α _inst_1)))) a)) (Neg.neg.{0} SignType SignType.instNegSignType (OrderHom.toFun.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (DistribLattice.toLattice.{0} SignType (instDistribLattice.{0} SignType SignType.instLinearOrderSignType))))) (SignType.sign.{u1} α (NegZeroClass.toZero.{u1} α (SubNegZeroMonoid.toNegZeroClass.{u1} α (SubtractionMonoid.toSubNegZeroMonoid.{u1} α (AddGroup.toSubtractionMonoid.{u1} α _inst_1)))) _inst_2 (fun (a : α) (b : α) => _inst_3 a b)) a))
 Case conversion may be inaccurate. Consider using '#align right.sign_neg Right.sign_negₓ'. -/
 theorem Right.sign_neg [CovariantClass α α (Function.swap (· + ·)) (· < ·)] (a : α) :
     SignType.sign (-a) = -SignType.sign a :=

mathlib commit https://github.com/leanprover-community/mathlib/commit/3180fab693e2cee3bff62675571264cb8778b212

@@ -368,7 +368,7 @@ variable [Zero α] [Preorder α] [DecidableRel ((· < ·) : α → α → Prop)]
 lean 3 declaration is
   forall {α : Type.{u1}} [_inst_1 : Zero.{u1} α] [_inst_2 : Preorder.{u1} α] [_inst_3 : DecidableRel.{succ u1} α (LT.lt.{u1} α (Preorder.toLT.{u1} α _inst_2))], OrderHom.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))
 but is expected to have type
-  forall {α : Type.{u1}} [_inst_1 : Zero.{u1} α] [_inst_2 : Preorder.{u1} α] [_inst_3 : DecidableRel.{succ u1} α (fun (x._@.Mathlib.Data.Sign._hyg.5019 : α) (x._@.Mathlib.Data.Sign._hyg.5021 : α) => LT.lt.{u1} α (Preorder.toLT.{u1} α _inst_2) x._@.Mathlib.Data.Sign._hyg.5019 x._@.Mathlib.Data.Sign._hyg.5021)], OrderHom.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (DistribLattice.toLattice.{0} SignType (instDistribLattice.{0} SignType SignType.instLinearOrderSignType)))))
+  forall {α : Type.{u1}} [_inst_1 : Zero.{u1} α] [_inst_2 : Preorder.{u1} α] [_inst_3 : DecidableRel.{succ u1} α (fun (x._@.Mathlib.Data.Sign._hyg.5020 : α) (x._@.Mathlib.Data.Sign._hyg.5022 : α) => LT.lt.{u1} α (Preorder.toLT.{u1} α _inst_2) x._@.Mathlib.Data.Sign._hyg.5020 x._@.Mathlib.Data.Sign._hyg.5022)], OrderHom.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (DistribLattice.toLattice.{0} SignType (instDistribLattice.{0} SignType SignType.instLinearOrderSignType)))))
 Case conversion may be inaccurate. Consider using '#align sign SignType.signₓ'. -/
 /-- The sign of an element is 1 if it's positive, -1 if negative, 0 otherwise. -/
 def SignType.sign : α →o SignType :=
@@ -483,7 +483,7 @@ variable [OrderedSemiring α] [DecidableRel ((· < ·) : α → α → Prop)] [N
 lean 3 declaration is
   forall {α : Type.{u1}} [_inst_1 : OrderedSemiring.{u1} α] [_inst_2 : DecidableRel.{succ u1} α (LT.lt.{u1} α (Preorder.toLT.{u1} α (PartialOrder.toPreorder.{u1} α (OrderedAddCommMonoid.toPartialOrder.{u1} α (OrderedSemiring.toOrderedAddCommMonoid.{u1} α _inst_1)))))] [_inst_3 : Nontrivial.{u1} α], Eq.{1} SignType (coeFn.{succ u1, succ u1} (OrderHom.{u1, 0} α SignType (PartialOrder.toPreorder.{u1} α (OrderedAddCommMonoid.toPartialOrder.{u1} α (OrderedSemiring.toOrderedAddCommMonoid.{u1} α _inst_1))) (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) (fun (_x : OrderHom.{u1, 0} α SignType (PartialOrder.toPreorder.{u1} α (OrderedAddCommMonoid.toPartialOrder.{u1} α (OrderedSemiring.toOrderedAddCommMonoid.{u1} α _inst_1))) (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) => α -> SignType) (OrderHom.hasCoeToFun.{u1, 0} α SignType (PartialOrder.toPreorder.{u1} α (OrderedAddCommMonoid.toPartialOrder.{u1} α (OrderedSemiring.toOrderedAddCommMonoid.{u1} α _inst_1))) (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) (SignType.sign.{u1} α (MulZeroClass.toHasZero.{u1} α (NonUnitalNonAssocSemiring.toMulZeroClass.{u1} α (NonAssocSemiring.toNonUnitalNonAssocSemiring.{u1} α (Semiring.toNonAssocSemiring.{u1} α (OrderedSemiring.toSemiring.{u1} α _inst_1))))) (PartialOrder.toPreorder.{u1} α (OrderedAddCommMonoid.toPartialOrder.{u1} α (OrderedSemiring.toOrderedAddCommMonoid.{u1} α _inst_1))) (fun (a : α) (b : α) => _inst_2 a b)) (OfNat.ofNat.{u1} α 1 (OfNat.mk.{u1} α 1 (One.one.{u1} α (AddMonoidWithOne.toOne.{u1} α (AddCommMonoidWithOne.toAddMonoidWithOne.{u1} α (NonAssocSemiring.toAddCommMonoidWithOne.{u1} α (Semiring.toNonAssocSemiring.{u1} α (OrderedSemiring.toSemiring.{u1} α _inst_1))))))))) (OfNat.ofNat.{0} SignType 1 (OfNat.mk.{0} SignType 1 (One.one.{0} SignType SignType.hasOne)))
 but is expected to have type
-  forall {α : Type.{u1}} [_inst_1 : OrderedSemiring.{u1} α] [_inst_2 : DecidableRel.{succ u1} α (fun (x._@.Mathlib.Data.Sign._hyg.5968 : α) (x._@.Mathlib.Data.Sign._hyg.5970 : α) => LT.lt.{u1} α (Preorder.toLT.{u1} α (PartialOrder.toPreorder.{u1} α (OrderedSemiring.toPartialOrder.{u1} α _inst_1))) x._@.Mathlib.Data.Sign._hyg.5968 x._@.Mathlib.Data.Sign._hyg.5970)] [_inst_3 : Nontrivial.{u1} α], Eq.{1} SignType (OrderHom.toFun.{u1, 0} α SignType (PartialOrder.toPreorder.{u1} α (OrderedSemiring.toPartialOrder.{u1} α _inst_1)) (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (DistribLattice.toLattice.{0} SignType (instDistribLattice.{0} SignType SignType.instLinearOrderSignType))))) (SignType.sign.{u1} α (MonoidWithZero.toZero.{u1} α (Semiring.toMonoidWithZero.{u1} α (OrderedSemiring.toSemiring.{u1} α _inst_1))) (PartialOrder.toPreorder.{u1} α (OrderedSemiring.toPartialOrder.{u1} α _inst_1)) (fun (a : α) (b : α) => _inst_2 a b)) (OfNat.ofNat.{u1} α 1 (One.toOfNat1.{u1} α (Semiring.toOne.{u1} α (OrderedSemiring.toSemiring.{u1} α _inst_1))))) (OfNat.ofNat.{0} SignType 1 (One.toOfNat1.{0} SignType SignType.instOneSignType))
+  forall {α : Type.{u1}} [_inst_1 : OrderedSemiring.{u1} α] [_inst_2 : DecidableRel.{succ u1} α (fun (x._@.Mathlib.Data.Sign._hyg.5979 : α) (x._@.Mathlib.Data.Sign._hyg.5981 : α) => LT.lt.{u1} α (Preorder.toLT.{u1} α (PartialOrder.toPreorder.{u1} α (OrderedSemiring.toPartialOrder.{u1} α _inst_1))) x._@.Mathlib.Data.Sign._hyg.5979 x._@.Mathlib.Data.Sign._hyg.5981)] [_inst_3 : Nontrivial.{u1} α], Eq.{1} SignType (OrderHom.toFun.{u1, 0} α SignType (PartialOrder.toPreorder.{u1} α (OrderedSemiring.toPartialOrder.{u1} α _inst_1)) (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (DistribLattice.toLattice.{0} SignType (instDistribLattice.{0} SignType SignType.instLinearOrderSignType))))) (SignType.sign.{u1} α (MonoidWithZero.toZero.{u1} α (Semiring.toMonoidWithZero.{u1} α (OrderedSemiring.toSemiring.{u1} α _inst_1))) (PartialOrder.toPreorder.{u1} α (OrderedSemiring.toPartialOrder.{u1} α _inst_1)) (fun (a : α) (b : α) => _inst_2 a b)) (OfNat.ofNat.{u1} α 1 (One.toOfNat1.{u1} α (Semiring.toOne.{u1} α (OrderedSemiring.toSemiring.{u1} α _inst_1))))) (OfNat.ofNat.{0} SignType 1 (One.toOfNat1.{0} SignType SignType.instOneSignType))
 Case conversion may be inaccurate. Consider using '#align sign_one sign_oneₓ'. -/
 @[simp]
 theorem sign_one : SignType.sign (1 : α) = 1 :=
@@ -552,7 +552,7 @@ variable [AddGroup α] [Preorder α] [DecidableRel ((· < ·) : α → α → Pr
 lean 3 declaration is
   forall {α : Type.{u1}} [_inst_1 : AddGroup.{u1} α] [_inst_2 : Preorder.{u1} α] [_inst_3 : DecidableRel.{succ u1} α (LT.lt.{u1} α (Preorder.toLT.{u1} α _inst_2))] [_inst_4 : CovariantClass.{u1, u1} α α (HAdd.hAdd.{u1, u1, u1} α α α (instHAdd.{u1} α (AddZeroClass.toHasAdd.{u1} α (AddMonoid.toAddZeroClass.{u1} α (SubNegMonoid.toAddMonoid.{u1} α (AddGroup.toSubNegMonoid.{u1} α _inst_1)))))) (LT.lt.{u1} α (Preorder.toLT.{u1} α _inst_2))] (a : α), Eq.{1} SignType (coeFn.{succ u1, succ u1} (OrderHom.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) (fun (_x : OrderHom.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) => α -> SignType) (OrderHom.hasCoeToFun.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) (SignType.sign.{u1} α (AddZeroClass.toHasZero.{u1} α (AddMonoid.toAddZeroClass.{u1} α (SubNegMonoid.toAddMonoid.{u1} α (AddGroup.toSubNegMonoid.{u1} α _inst_1)))) _inst_2 (fun (a : α) (b : α) => _inst_3 a b)) (Neg.neg.{u1} α (SubNegMonoid.toHasNeg.{u1} α (AddGroup.toSubNegMonoid.{u1} α _inst_1)) a)) (Neg.neg.{0} SignType SignType.hasNeg (coeFn.{succ u1, succ u1} (OrderHom.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) (fun (_x : OrderHom.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) => α -> SignType) (OrderHom.hasCoeToFun.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) (SignType.sign.{u1} α (AddZeroClass.toHasZero.{u1} α (AddMonoid.toAddZeroClass.{u1} α (SubNegMonoid.toAddMonoid.{u1} α (AddGroup.toSubNegMonoid.{u1} α _inst_1)))) _inst_2 (fun (a : α) (b : α) => _inst_3 a b)) a))
 but is expected to have type
-  forall {α : Type.{u1}} [_inst_1 : AddGroup.{u1} α] [_inst_2 : Preorder.{u1} α] [_inst_3 : DecidableRel.{succ u1} α (fun (x._@.Mathlib.Data.Sign._hyg.6480 : α) (x._@.Mathlib.Data.Sign._hyg.6482 : α) => LT.lt.{u1} α (Preorder.toLT.{u1} α _inst_2) x._@.Mathlib.Data.Sign._hyg.6480 x._@.Mathlib.Data.Sign._hyg.6482)] [_inst_4 : CovariantClass.{u1, u1} α α (fun (x._@.Mathlib.Data.Sign._hyg.6499 : α) (x._@.Mathlib.Data.Sign._hyg.6501 : α) => HAdd.hAdd.{u1, u1, u1} α α α (instHAdd.{u1} α (AddZeroClass.toAdd.{u1} α (AddMonoid.toAddZeroClass.{u1} α (SubNegMonoid.toAddMonoid.{u1} α (AddGroup.toSubNegMonoid.{u1} α _inst_1))))) x._@.Mathlib.Data.Sign._hyg.6499 x._@.Mathlib.Data.Sign._hyg.6501) (fun (x._@.Mathlib.Data.Sign._hyg.6514 : α) (x._@.Mathlib.Data.Sign._hyg.6516 : α) => LT.lt.{u1} α (Preorder.toLT.{u1} α _inst_2) x._@.Mathlib.Data.Sign._hyg.6514 x._@.Mathlib.Data.Sign._hyg.6516)] (a : α), Eq.{1} SignType (OrderHom.toFun.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (DistribLattice.toLattice.{0} SignType (instDistribLattice.{0} SignType SignType.instLinearOrderSignType))))) (SignType.sign.{u1} α (NegZeroClass.toZero.{u1} α (SubNegZeroMonoid.toNegZeroClass.{u1} α (SubtractionMonoid.toSubNegZeroMonoid.{u1} α (AddGroup.toSubtractionMonoid.{u1} α _inst_1)))) _inst_2 (fun (a : α) (b : α) => _inst_3 a b)) (Neg.neg.{u1} α (NegZeroClass.toNeg.{u1} α (SubNegZeroMonoid.toNegZeroClass.{u1} α (SubtractionMonoid.toSubNegZeroMonoid.{u1} α (AddGroup.toSubtractionMonoid.{u1} α _inst_1)))) a)) (Neg.neg.{0} SignType SignType.instNegSignType (OrderHom.toFun.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (DistribLattice.toLattice.{0} SignType (instDistribLattice.{0} SignType SignType.instLinearOrderSignType))))) (SignType.sign.{u1} α (NegZeroClass.toZero.{u1} α (SubNegZeroMonoid.toNegZeroClass.{u1} α (SubtractionMonoid.toSubNegZeroMonoid.{u1} α (AddGroup.toSubtractionMonoid.{u1} α _inst_1)))) _inst_2 (fun (a : α) (b : α) => _inst_3 a b)) a))
+  forall {α : Type.{u1}} [_inst_1 : AddGroup.{u1} α] [_inst_2 : Preorder.{u1} α] [_inst_3 : DecidableRel.{succ u1} α (fun (x._@.Mathlib.Data.Sign._hyg.6500 : α) (x._@.Mathlib.Data.Sign._hyg.6502 : α) => LT.lt.{u1} α (Preorder.toLT.{u1} α _inst_2) x._@.Mathlib.Data.Sign._hyg.6500 x._@.Mathlib.Data.Sign._hyg.6502)] [_inst_4 : CovariantClass.{u1, u1} α α (fun (x._@.Mathlib.Data.Sign._hyg.6519 : α) (x._@.Mathlib.Data.Sign._hyg.6521 : α) => HAdd.hAdd.{u1, u1, u1} α α α (instHAdd.{u1} α (AddZeroClass.toAdd.{u1} α (AddMonoid.toAddZeroClass.{u1} α (SubNegMonoid.toAddMonoid.{u1} α (AddGroup.toSubNegMonoid.{u1} α _inst_1))))) x._@.Mathlib.Data.Sign._hyg.6519 x._@.Mathlib.Data.Sign._hyg.6521) (fun (x._@.Mathlib.Data.Sign._hyg.6534 : α) (x._@.Mathlib.Data.Sign._hyg.6536 : α) => LT.lt.{u1} α (Preorder.toLT.{u1} α _inst_2) x._@.Mathlib.Data.Sign._hyg.6534 x._@.Mathlib.Data.Sign._hyg.6536)] (a : α), Eq.{1} SignType (OrderHom.toFun.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (DistribLattice.toLattice.{0} SignType (instDistribLattice.{0} SignType SignType.instLinearOrderSignType))))) (SignType.sign.{u1} α (NegZeroClass.toZero.{u1} α (SubNegZeroMonoid.toNegZeroClass.{u1} α (SubtractionMonoid.toSubNegZeroMonoid.{u1} α (AddGroup.toSubtractionMonoid.{u1} α _inst_1)))) _inst_2 (fun (a : α) (b : α) => _inst_3 a b)) (Neg.neg.{u1} α (NegZeroClass.toNeg.{u1} α (SubNegZeroMonoid.toNegZeroClass.{u1} α (SubtractionMonoid.toSubNegZeroMonoid.{u1} α (AddGroup.toSubtractionMonoid.{u1} α _inst_1)))) a)) (Neg.neg.{0} SignType SignType.instNegSignType (OrderHom.toFun.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (DistribLattice.toLattice.{0} SignType (instDistribLattice.{0} SignType SignType.instLinearOrderSignType))))) (SignType.sign.{u1} α (NegZeroClass.toZero.{u1} α (SubNegZeroMonoid.toNegZeroClass.{u1} α (SubtractionMonoid.toSubNegZeroMonoid.{u1} α (AddGroup.toSubtractionMonoid.{u1} α _inst_1)))) _inst_2 (fun (a : α) (b : α) => _inst_3 a b)) a))
 Case conversion may be inaccurate. Consider using '#align left.sign_neg Left.sign_negₓ'. -/
 theorem Left.sign_neg [CovariantClass α α (· + ·) (· < ·)] (a : α) :
     SignType.sign (-a) = -SignType.sign a :=
@@ -569,7 +569,7 @@ theorem Left.sign_neg [CovariantClass α α (· + ·) (· < ·)] (a : α) :
 lean 3 declaration is
   forall {α : Type.{u1}} [_inst_1 : AddGroup.{u1} α] [_inst_2 : Preorder.{u1} α] [_inst_3 : DecidableRel.{succ u1} α (LT.lt.{u1} α (Preorder.toLT.{u1} α _inst_2))] [_inst_4 : CovariantClass.{u1, u1} α α (Function.swap.{succ u1, succ u1, succ u1} α α (fun (ᾰ : α) (ᾰ : α) => α) (HAdd.hAdd.{u1, u1, u1} α α α (instHAdd.{u1} α (AddZeroClass.toHasAdd.{u1} α (AddMonoid.toAddZeroClass.{u1} α (SubNegMonoid.toAddMonoid.{u1} α (AddGroup.toSubNegMonoid.{u1} α _inst_1))))))) (LT.lt.{u1} α (Preorder.toLT.{u1} α _inst_2))] (a : α), Eq.{1} SignType (coeFn.{succ u1, succ u1} (OrderHom.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) (fun (_x : OrderHom.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) => α -> SignType) (OrderHom.hasCoeToFun.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) (SignType.sign.{u1} α (AddZeroClass.toHasZero.{u1} α (AddMonoid.toAddZeroClass.{u1} α (SubNegMonoid.toAddMonoid.{u1} α (AddGroup.toSubNegMonoid.{u1} α _inst_1)))) _inst_2 (fun (a : α) (b : α) => _inst_3 a b)) (Neg.neg.{u1} α (SubNegMonoid.toHasNeg.{u1} α (AddGroup.toSubNegMonoid.{u1} α _inst_1)) a)) (Neg.neg.{0} SignType SignType.hasNeg (coeFn.{succ u1, succ u1} (OrderHom.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) (fun (_x : OrderHom.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) => α -> SignType) (OrderHom.hasCoeToFun.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) (SignType.sign.{u1} α (AddZeroClass.toHasZero.{u1} α (AddMonoid.toAddZeroClass.{u1} α (SubNegMonoid.toAddMonoid.{u1} α (AddGroup.toSubNegMonoid.{u1} α _inst_1)))) _inst_2 (fun (a : α) (b : α) => _inst_3 a b)) a))
 but is expected to have type
-  forall {α : Type.{u1}} [_inst_1 : AddGroup.{u1} α] [_inst_2 : Preorder.{u1} α] [_inst_3 : DecidableRel.{succ u1} α (fun (x._@.Mathlib.Data.Sign._hyg.6598 : α) (x._@.Mathlib.Data.Sign._hyg.6600 : α) => LT.lt.{u1} α (Preorder.toLT.{u1} α _inst_2) x._@.Mathlib.Data.Sign._hyg.6598 x._@.Mathlib.Data.Sign._hyg.6600)] [_inst_4 : CovariantClass.{u1, u1} α α (Function.swap.{succ u1, succ u1, succ u1} α α (fun (ᾰ : α) (ᾰ : α) => α) (fun (x._@.Mathlib.Data.Sign._hyg.6620 : α) (x._@.Mathlib.Data.Sign._hyg.6622 : α) => HAdd.hAdd.{u1, u1, u1} α α α (instHAdd.{u1} α (AddZeroClass.toAdd.{u1} α (AddMonoid.toAddZeroClass.{u1} α (SubNegMonoid.toAddMonoid.{u1} α (AddGroup.toSubNegMonoid.{u1} α _inst_1))))) x._@.Mathlib.Data.Sign._hyg.6620 x._@.Mathlib.Data.Sign._hyg.6622)) (fun (x._@.Mathlib.Data.Sign._hyg.6635 : α) (x._@.Mathlib.Data.Sign._hyg.6637 : α) => LT.lt.{u1} α (Preorder.toLT.{u1} α _inst_2) x._@.Mathlib.Data.Sign._hyg.6635 x._@.Mathlib.Data.Sign._hyg.6637)] (a : α), Eq.{1} SignType (OrderHom.toFun.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (DistribLattice.toLattice.{0} SignType (instDistribLattice.{0} SignType SignType.instLinearOrderSignType))))) (SignType.sign.{u1} α (NegZeroClass.toZero.{u1} α (SubNegZeroMonoid.toNegZeroClass.{u1} α (SubtractionMonoid.toSubNegZeroMonoid.{u1} α (AddGroup.toSubtractionMonoid.{u1} α _inst_1)))) _inst_2 (fun (a : α) (b : α) => _inst_3 a b)) (Neg.neg.{u1} α (NegZeroClass.toNeg.{u1} α (SubNegZeroMonoid.toNegZeroClass.{u1} α (SubtractionMonoid.toSubNegZeroMonoid.{u1} α (AddGroup.toSubtractionMonoid.{u1} α _inst_1)))) a)) (Neg.neg.{0} SignType SignType.instNegSignType (OrderHom.toFun.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (DistribLattice.toLattice.{0} SignType (instDistribLattice.{0} SignType SignType.instLinearOrderSignType))))) (SignType.sign.{u1} α (NegZeroClass.toZero.{u1} α (SubNegZeroMonoid.toNegZeroClass.{u1} α (SubtractionMonoid.toSubNegZeroMonoid.{u1} α (AddGroup.toSubtractionMonoid.{u1} α _inst_1)))) _inst_2 (fun (a : α) (b : α) => _inst_3 a b)) a))
+  forall {α : Type.{u1}} [_inst_1 : AddGroup.{u1} α] [_inst_2 : Preorder.{u1} α] [_inst_3 : DecidableRel.{succ u1} α (fun (x._@.Mathlib.Data.Sign._hyg.6620 : α) (x._@.Mathlib.Data.Sign._hyg.6622 : α) => LT.lt.{u1} α (Preorder.toLT.{u1} α _inst_2) x._@.Mathlib.Data.Sign._hyg.6620 x._@.Mathlib.Data.Sign._hyg.6622)] [_inst_4 : CovariantClass.{u1, u1} α α (Function.swap.{succ u1, succ u1, succ u1} α α (fun (ᾰ : α) (ᾰ : α) => α) (fun (x._@.Mathlib.Data.Sign._hyg.6642 : α) (x._@.Mathlib.Data.Sign._hyg.6644 : α) => HAdd.hAdd.{u1, u1, u1} α α α (instHAdd.{u1} α (AddZeroClass.toAdd.{u1} α (AddMonoid.toAddZeroClass.{u1} α (SubNegMonoid.toAddMonoid.{u1} α (AddGroup.toSubNegMonoid.{u1} α _inst_1))))) x._@.Mathlib.Data.Sign._hyg.6642 x._@.Mathlib.Data.Sign._hyg.6644)) (fun (x._@.Mathlib.Data.Sign._hyg.6657 : α) (x._@.Mathlib.Data.Sign._hyg.6659 : α) => LT.lt.{u1} α (Preorder.toLT.{u1} α _inst_2) x._@.Mathlib.Data.Sign._hyg.6657 x._@.Mathlib.Data.Sign._hyg.6659)] (a : α), Eq.{1} SignType (OrderHom.toFun.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (DistribLattice.toLattice.{0} SignType (instDistribLattice.{0} SignType SignType.instLinearOrderSignType))))) (SignType.sign.{u1} α (NegZeroClass.toZero.{u1} α (SubNegZeroMonoid.toNegZeroClass.{u1} α (SubtractionMonoid.toSubNegZeroMonoid.{u1} α (AddGroup.toSubtractionMonoid.{u1} α _inst_1)))) _inst_2 (fun (a : α) (b : α) => _inst_3 a b)) (Neg.neg.{u1} α (NegZeroClass.toNeg.{u1} α (SubNegZeroMonoid.toNegZeroClass.{u1} α (SubtractionMonoid.toSubNegZeroMonoid.{u1} α (AddGroup.toSubtractionMonoid.{u1} α _inst_1)))) a)) (Neg.neg.{0} SignType SignType.instNegSignType (OrderHom.toFun.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (DistribLattice.toLattice.{0} SignType (instDistribLattice.{0} SignType SignType.instLinearOrderSignType))))) (SignType.sign.{u1} α (NegZeroClass.toZero.{u1} α (SubNegZeroMonoid.toNegZeroClass.{u1} α (SubtractionMonoid.toSubNegZeroMonoid.{u1} α (AddGroup.toSubtractionMonoid.{u1} α _inst_1)))) _inst_2 (fun (a : α) (b : α) => _inst_3 a b)) a))
 Case conversion may be inaccurate. Consider using '#align right.sign_neg Right.sign_negₓ'. -/
 theorem Right.sign_neg [CovariantClass α α (Function.swap (· + ·)) (· < ·)] (a : α) :
     SignType.sign (-a) = -SignType.sign a :=

mathlib commit https://github.com/leanprover-community/mathlib/commit/3180fab693e2cee3bff62675571264cb8778b212

@@ -508,9 +508,9 @@ but is expected to have type
 Case conversion may be inaccurate. Consider using '#align sign_mul sign_mulₓ'. -/
 theorem sign_mul (x y : α) : SignType.sign (x * y) = SignType.sign x * SignType.sign y := by
   rcases lt_trichotomy x 0 with (hx | hx | hx) <;> rcases lt_trichotomy y 0 with (hy | hy | hy) <;>
-    simp only [sign_zero, mul_zero, zero_mul, sign_pos, sign_neg, hx, hy, mul_one, neg_one_mul,
-      neg_neg, one_mul, mul_pos_of_neg_of_neg, mul_neg_of_neg_of_pos, neg_zero,
-      mul_neg_of_pos_of_neg, mul_pos]
+    simp only [sign_zero, MulZeroClass.mul_zero, MulZeroClass.zero_mul, sign_pos, sign_neg, hx, hy,
+      mul_one, neg_one_mul, neg_neg, one_mul, mul_pos_of_neg_of_neg, mul_neg_of_neg_of_pos,
+      neg_zero, mul_neg_of_pos_of_neg, mul_pos]
 #align sign_mul sign_mul
 
 /- warning: sign_hom -> signHom is a dubious translation:

mathlib commit https://github.com/leanprover-community/mathlib/commit/3b267e70a936eebb21ab546f49a8df34dd300b25

@@ -368,7 +368,7 @@ variable [Zero α] [Preorder α] [DecidableRel ((· < ·) : α → α → Prop)]
 lean 3 declaration is
   forall {α : Type.{u1}} [_inst_1 : Zero.{u1} α] [_inst_2 : Preorder.{u1} α] [_inst_3 : DecidableRel.{succ u1} α (LT.lt.{u1} α (Preorder.toLT.{u1} α _inst_2))], OrderHom.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))
 but is expected to have type
-  forall {α : Type.{u1}} [_inst_1 : Zero.{u1} α] [_inst_2 : Preorder.{u1} α] [_inst_3 : DecidableRel.{succ u1} α (fun (x._@.Mathlib.Data.Sign._hyg.5013 : α) (x._@.Mathlib.Data.Sign._hyg.5015 : α) => LT.lt.{u1} α (Preorder.toLT.{u1} α _inst_2) x._@.Mathlib.Data.Sign._hyg.5013 x._@.Mathlib.Data.Sign._hyg.5015)], OrderHom.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (DistribLattice.toLattice.{0} SignType (instDistribLattice.{0} SignType SignType.instLinearOrderSignType)))))
+  forall {α : Type.{u1}} [_inst_1 : Zero.{u1} α] [_inst_2 : Preorder.{u1} α] [_inst_3 : DecidableRel.{succ u1} α (fun (x._@.Mathlib.Data.Sign._hyg.5019 : α) (x._@.Mathlib.Data.Sign._hyg.5021 : α) => LT.lt.{u1} α (Preorder.toLT.{u1} α _inst_2) x._@.Mathlib.Data.Sign._hyg.5019 x._@.Mathlib.Data.Sign._hyg.5021)], OrderHom.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (DistribLattice.toLattice.{0} SignType (instDistribLattice.{0} SignType SignType.instLinearOrderSignType)))))
 Case conversion may be inaccurate. Consider using '#align sign SignType.signₓ'. -/
 /-- The sign of an element is 1 if it's positive, -1 if negative, 0 otherwise. -/
 def SignType.sign : α →o SignType :=
@@ -483,7 +483,7 @@ variable [OrderedSemiring α] [DecidableRel ((· < ·) : α → α → Prop)] [N
 lean 3 declaration is
   forall {α : Type.{u1}} [_inst_1 : OrderedSemiring.{u1} α] [_inst_2 : DecidableRel.{succ u1} α (LT.lt.{u1} α (Preorder.toLT.{u1} α (PartialOrder.toPreorder.{u1} α (OrderedAddCommMonoid.toPartialOrder.{u1} α (OrderedSemiring.toOrderedAddCommMonoid.{u1} α _inst_1)))))] [_inst_3 : Nontrivial.{u1} α], Eq.{1} SignType (coeFn.{succ u1, succ u1} (OrderHom.{u1, 0} α SignType (PartialOrder.toPreorder.{u1} α (OrderedAddCommMonoid.toPartialOrder.{u1} α (OrderedSemiring.toOrderedAddCommMonoid.{u1} α _inst_1))) (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) (fun (_x : OrderHom.{u1, 0} α SignType (PartialOrder.toPreorder.{u1} α (OrderedAddCommMonoid.toPartialOrder.{u1} α (OrderedSemiring.toOrderedAddCommMonoid.{u1} α _inst_1))) (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) => α -> SignType) (OrderHom.hasCoeToFun.{u1, 0} α SignType (PartialOrder.toPreorder.{u1} α (OrderedAddCommMonoid.toPartialOrder.{u1} α (OrderedSemiring.toOrderedAddCommMonoid.{u1} α _inst_1))) (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) (SignType.sign.{u1} α (MulZeroClass.toHasZero.{u1} α (NonUnitalNonAssocSemiring.toMulZeroClass.{u1} α (NonAssocSemiring.toNonUnitalNonAssocSemiring.{u1} α (Semiring.toNonAssocSemiring.{u1} α (OrderedSemiring.toSemiring.{u1} α _inst_1))))) (PartialOrder.toPreorder.{u1} α (OrderedAddCommMonoid.toPartialOrder.{u1} α (OrderedSemiring.toOrderedAddCommMonoid.{u1} α _inst_1))) (fun (a : α) (b : α) => _inst_2 a b)) (OfNat.ofNat.{u1} α 1 (OfNat.mk.{u1} α 1 (One.one.{u1} α (AddMonoidWithOne.toOne.{u1} α (AddCommMonoidWithOne.toAddMonoidWithOne.{u1} α (NonAssocSemiring.toAddCommMonoidWithOne.{u1} α (Semiring.toNonAssocSemiring.{u1} α (OrderedSemiring.toSemiring.{u1} α _inst_1))))))))) (OfNat.ofNat.{0} SignType 1 (OfNat.mk.{0} SignType 1 (One.one.{0} SignType SignType.hasOne)))
 but is expected to have type
-  forall {α : Type.{u1}} [_inst_1 : OrderedSemiring.{u1} α] [_inst_2 : DecidableRel.{succ u1} α (fun (x._@.Mathlib.Data.Sign._hyg.5962 : α) (x._@.Mathlib.Data.Sign._hyg.5964 : α) => LT.lt.{u1} α (Preorder.toLT.{u1} α (PartialOrder.toPreorder.{u1} α (OrderedSemiring.toPartialOrder.{u1} α _inst_1))) x._@.Mathlib.Data.Sign._hyg.5962 x._@.Mathlib.Data.Sign._hyg.5964)] [_inst_3 : Nontrivial.{u1} α], Eq.{1} SignType (OrderHom.toFun.{u1, 0} α SignType (PartialOrder.toPreorder.{u1} α (OrderedSemiring.toPartialOrder.{u1} α _inst_1)) (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (DistribLattice.toLattice.{0} SignType (instDistribLattice.{0} SignType SignType.instLinearOrderSignType))))) (SignType.sign.{u1} α (MonoidWithZero.toZero.{u1} α (Semiring.toMonoidWithZero.{u1} α (OrderedSemiring.toSemiring.{u1} α _inst_1))) (PartialOrder.toPreorder.{u1} α (OrderedSemiring.toPartialOrder.{u1} α _inst_1)) (fun (a : α) (b : α) => _inst_2 a b)) (OfNat.ofNat.{u1} α 1 (One.toOfNat1.{u1} α (Semiring.toOne.{u1} α (OrderedSemiring.toSemiring.{u1} α _inst_1))))) (OfNat.ofNat.{0} SignType 1 (One.toOfNat1.{0} SignType SignType.instOneSignType))
+  forall {α : Type.{u1}} [_inst_1 : OrderedSemiring.{u1} α] [_inst_2 : DecidableRel.{succ u1} α (fun (x._@.Mathlib.Data.Sign._hyg.5968 : α) (x._@.Mathlib.Data.Sign._hyg.5970 : α) => LT.lt.{u1} α (Preorder.toLT.{u1} α (PartialOrder.toPreorder.{u1} α (OrderedSemiring.toPartialOrder.{u1} α _inst_1))) x._@.Mathlib.Data.Sign._hyg.5968 x._@.Mathlib.Data.Sign._hyg.5970)] [_inst_3 : Nontrivial.{u1} α], Eq.{1} SignType (OrderHom.toFun.{u1, 0} α SignType (PartialOrder.toPreorder.{u1} α (OrderedSemiring.toPartialOrder.{u1} α _inst_1)) (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (DistribLattice.toLattice.{0} SignType (instDistribLattice.{0} SignType SignType.instLinearOrderSignType))))) (SignType.sign.{u1} α (MonoidWithZero.toZero.{u1} α (Semiring.toMonoidWithZero.{u1} α (OrderedSemiring.toSemiring.{u1} α _inst_1))) (PartialOrder.toPreorder.{u1} α (OrderedSemiring.toPartialOrder.{u1} α _inst_1)) (fun (a : α) (b : α) => _inst_2 a b)) (OfNat.ofNat.{u1} α 1 (One.toOfNat1.{u1} α (Semiring.toOne.{u1} α (OrderedSemiring.toSemiring.{u1} α _inst_1))))) (OfNat.ofNat.{0} SignType 1 (One.toOfNat1.{0} SignType SignType.instOneSignType))
 Case conversion may be inaccurate. Consider using '#align sign_one sign_oneₓ'. -/
 @[simp]
 theorem sign_one : SignType.sign (1 : α) = 1 :=
@@ -552,7 +552,7 @@ variable [AddGroup α] [Preorder α] [DecidableRel ((· < ·) : α → α → Pr
 lean 3 declaration is
   forall {α : Type.{u1}} [_inst_1 : AddGroup.{u1} α] [_inst_2 : Preorder.{u1} α] [_inst_3 : DecidableRel.{succ u1} α (LT.lt.{u1} α (Preorder.toLT.{u1} α _inst_2))] [_inst_4 : CovariantClass.{u1, u1} α α (HAdd.hAdd.{u1, u1, u1} α α α (instHAdd.{u1} α (AddZeroClass.toHasAdd.{u1} α (AddMonoid.toAddZeroClass.{u1} α (SubNegMonoid.toAddMonoid.{u1} α (AddGroup.toSubNegMonoid.{u1} α _inst_1)))))) (LT.lt.{u1} α (Preorder.toLT.{u1} α _inst_2))] (a : α), Eq.{1} SignType (coeFn.{succ u1, succ u1} (OrderHom.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) (fun (_x : OrderHom.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) => α -> SignType) (OrderHom.hasCoeToFun.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) (SignType.sign.{u1} α (AddZeroClass.toHasZero.{u1} α (AddMonoid.toAddZeroClass.{u1} α (SubNegMonoid.toAddMonoid.{u1} α (AddGroup.toSubNegMonoid.{u1} α _inst_1)))) _inst_2 (fun (a : α) (b : α) => _inst_3 a b)) (Neg.neg.{u1} α (SubNegMonoid.toHasNeg.{u1} α (AddGroup.toSubNegMonoid.{u1} α _inst_1)) a)) (Neg.neg.{0} SignType SignType.hasNeg (coeFn.{succ u1, succ u1} (OrderHom.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) (fun (_x : OrderHom.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) => α -> SignType) (OrderHom.hasCoeToFun.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) (SignType.sign.{u1} α (AddZeroClass.toHasZero.{u1} α (AddMonoid.toAddZeroClass.{u1} α (SubNegMonoid.toAddMonoid.{u1} α (AddGroup.toSubNegMonoid.{u1} α _inst_1)))) _inst_2 (fun (a : α) (b : α) => _inst_3 a b)) a))
 but is expected to have type
-  forall {α : Type.{u1}} [_inst_1 : AddGroup.{u1} α] [_inst_2 : Preorder.{u1} α] [_inst_3 : DecidableRel.{succ u1} α (fun (x._@.Mathlib.Data.Sign._hyg.6474 : α) (x._@.Mathlib.Data.Sign._hyg.6476 : α) => LT.lt.{u1} α (Preorder.toLT.{u1} α _inst_2) x._@.Mathlib.Data.Sign._hyg.6474 x._@.Mathlib.Data.Sign._hyg.6476)] [_inst_4 : CovariantClass.{u1, u1} α α (fun (x._@.Mathlib.Data.Sign._hyg.6493 : α) (x._@.Mathlib.Data.Sign._hyg.6495 : α) => HAdd.hAdd.{u1, u1, u1} α α α (instHAdd.{u1} α (AddZeroClass.toAdd.{u1} α (AddMonoid.toAddZeroClass.{u1} α (SubNegMonoid.toAddMonoid.{u1} α (AddGroup.toSubNegMonoid.{u1} α _inst_1))))) x._@.Mathlib.Data.Sign._hyg.6493 x._@.Mathlib.Data.Sign._hyg.6495) (fun (x._@.Mathlib.Data.Sign._hyg.6508 : α) (x._@.Mathlib.Data.Sign._hyg.6510 : α) => LT.lt.{u1} α (Preorder.toLT.{u1} α _inst_2) x._@.Mathlib.Data.Sign._hyg.6508 x._@.Mathlib.Data.Sign._hyg.6510)] (a : α), Eq.{1} SignType (OrderHom.toFun.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (DistribLattice.toLattice.{0} SignType (instDistribLattice.{0} SignType SignType.instLinearOrderSignType))))) (SignType.sign.{u1} α (NegZeroClass.toZero.{u1} α (SubNegZeroMonoid.toNegZeroClass.{u1} α (SubtractionMonoid.toSubNegZeroMonoid.{u1} α (AddGroup.toSubtractionMonoid.{u1} α _inst_1)))) _inst_2 (fun (a : α) (b : α) => _inst_3 a b)) (Neg.neg.{u1} α (NegZeroClass.toNeg.{u1} α (SubNegZeroMonoid.toNegZeroClass.{u1} α (SubtractionMonoid.toSubNegZeroMonoid.{u1} α (AddGroup.toSubtractionMonoid.{u1} α _inst_1)))) a)) (Neg.neg.{0} SignType SignType.instNegSignType (OrderHom.toFun.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (DistribLattice.toLattice.{0} SignType (instDistribLattice.{0} SignType SignType.instLinearOrderSignType))))) (SignType.sign.{u1} α (NegZeroClass.toZero.{u1} α (SubNegZeroMonoid.toNegZeroClass.{u1} α (SubtractionMonoid.toSubNegZeroMonoid.{u1} α (AddGroup.toSubtractionMonoid.{u1} α _inst_1)))) _inst_2 (fun (a : α) (b : α) => _inst_3 a b)) a))
+  forall {α : Type.{u1}} [_inst_1 : AddGroup.{u1} α] [_inst_2 : Preorder.{u1} α] [_inst_3 : DecidableRel.{succ u1} α (fun (x._@.Mathlib.Data.Sign._hyg.6480 : α) (x._@.Mathlib.Data.Sign._hyg.6482 : α) => LT.lt.{u1} α (Preorder.toLT.{u1} α _inst_2) x._@.Mathlib.Data.Sign._hyg.6480 x._@.Mathlib.Data.Sign._hyg.6482)] [_inst_4 : CovariantClass.{u1, u1} α α (fun (x._@.Mathlib.Data.Sign._hyg.6499 : α) (x._@.Mathlib.Data.Sign._hyg.6501 : α) => HAdd.hAdd.{u1, u1, u1} α α α (instHAdd.{u1} α (AddZeroClass.toAdd.{u1} α (AddMonoid.toAddZeroClass.{u1} α (SubNegMonoid.toAddMonoid.{u1} α (AddGroup.toSubNegMonoid.{u1} α _inst_1))))) x._@.Mathlib.Data.Sign._hyg.6499 x._@.Mathlib.Data.Sign._hyg.6501) (fun (x._@.Mathlib.Data.Sign._hyg.6514 : α) (x._@.Mathlib.Data.Sign._hyg.6516 : α) => LT.lt.{u1} α (Preorder.toLT.{u1} α _inst_2) x._@.Mathlib.Data.Sign._hyg.6514 x._@.Mathlib.Data.Sign._hyg.6516)] (a : α), Eq.{1} SignType (OrderHom.toFun.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (DistribLattice.toLattice.{0} SignType (instDistribLattice.{0} SignType SignType.instLinearOrderSignType))))) (SignType.sign.{u1} α (NegZeroClass.toZero.{u1} α (SubNegZeroMonoid.toNegZeroClass.{u1} α (SubtractionMonoid.toSubNegZeroMonoid.{u1} α (AddGroup.toSubtractionMonoid.{u1} α _inst_1)))) _inst_2 (fun (a : α) (b : α) => _inst_3 a b)) (Neg.neg.{u1} α (NegZeroClass.toNeg.{u1} α (SubNegZeroMonoid.toNegZeroClass.{u1} α (SubtractionMonoid.toSubNegZeroMonoid.{u1} α (AddGroup.toSubtractionMonoid.{u1} α _inst_1)))) a)) (Neg.neg.{0} SignType SignType.instNegSignType (OrderHom.toFun.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (DistribLattice.toLattice.{0} SignType (instDistribLattice.{0} SignType SignType.instLinearOrderSignType))))) (SignType.sign.{u1} α (NegZeroClass.toZero.{u1} α (SubNegZeroMonoid.toNegZeroClass.{u1} α (SubtractionMonoid.toSubNegZeroMonoid.{u1} α (AddGroup.toSubtractionMonoid.{u1} α _inst_1)))) _inst_2 (fun (a : α) (b : α) => _inst_3 a b)) a))
 Case conversion may be inaccurate. Consider using '#align left.sign_neg Left.sign_negₓ'. -/
 theorem Left.sign_neg [CovariantClass α α (· + ·) (· < ·)] (a : α) :
     SignType.sign (-a) = -SignType.sign a :=
@@ -569,7 +569,7 @@ theorem Left.sign_neg [CovariantClass α α (· + ·) (· < ·)] (a : α) :
 lean 3 declaration is
   forall {α : Type.{u1}} [_inst_1 : AddGroup.{u1} α] [_inst_2 : Preorder.{u1} α] [_inst_3 : DecidableRel.{succ u1} α (LT.lt.{u1} α (Preorder.toLT.{u1} α _inst_2))] [_inst_4 : CovariantClass.{u1, u1} α α (Function.swap.{succ u1, succ u1, succ u1} α α (fun (ᾰ : α) (ᾰ : α) => α) (HAdd.hAdd.{u1, u1, u1} α α α (instHAdd.{u1} α (AddZeroClass.toHasAdd.{u1} α (AddMonoid.toAddZeroClass.{u1} α (SubNegMonoid.toAddMonoid.{u1} α (AddGroup.toSubNegMonoid.{u1} α _inst_1))))))) (LT.lt.{u1} α (Preorder.toLT.{u1} α _inst_2))] (a : α), Eq.{1} SignType (coeFn.{succ u1, succ u1} (OrderHom.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) (fun (_x : OrderHom.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) => α -> SignType) (OrderHom.hasCoeToFun.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) (SignType.sign.{u1} α (AddZeroClass.toHasZero.{u1} α (AddMonoid.toAddZeroClass.{u1} α (SubNegMonoid.toAddMonoid.{u1} α (AddGroup.toSubNegMonoid.{u1} α _inst_1)))) _inst_2 (fun (a : α) (b : α) => _inst_3 a b)) (Neg.neg.{u1} α (SubNegMonoid.toHasNeg.{u1} α (AddGroup.toSubNegMonoid.{u1} α _inst_1)) a)) (Neg.neg.{0} SignType SignType.hasNeg (coeFn.{succ u1, succ u1} (OrderHom.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) (fun (_x : OrderHom.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) => α -> SignType) (OrderHom.hasCoeToFun.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) (SignType.sign.{u1} α (AddZeroClass.toHasZero.{u1} α (AddMonoid.toAddZeroClass.{u1} α (SubNegMonoid.toAddMonoid.{u1} α (AddGroup.toSubNegMonoid.{u1} α _inst_1)))) _inst_2 (fun (a : α) (b : α) => _inst_3 a b)) a))
 but is expected to have type
-  forall {α : Type.{u1}} [_inst_1 : AddGroup.{u1} α] [_inst_2 : Preorder.{u1} α] [_inst_3 : DecidableRel.{succ u1} α (fun (x._@.Mathlib.Data.Sign._hyg.6592 : α) (x._@.Mathlib.Data.Sign._hyg.6594 : α) => LT.lt.{u1} α (Preorder.toLT.{u1} α _inst_2) x._@.Mathlib.Data.Sign._hyg.6592 x._@.Mathlib.Data.Sign._hyg.6594)] [_inst_4 : CovariantClass.{u1, u1} α α (Function.swap.{succ u1, succ u1, succ u1} α α (fun (ᾰ : α) (ᾰ : α) => α) (fun (x._@.Mathlib.Data.Sign._hyg.6614 : α) (x._@.Mathlib.Data.Sign._hyg.6616 : α) => HAdd.hAdd.{u1, u1, u1} α α α (instHAdd.{u1} α (AddZeroClass.toAdd.{u1} α (AddMonoid.toAddZeroClass.{u1} α (SubNegMonoid.toAddMonoid.{u1} α (AddGroup.toSubNegMonoid.{u1} α _inst_1))))) x._@.Mathlib.Data.Sign._hyg.6614 x._@.Mathlib.Data.Sign._hyg.6616)) (fun (x._@.Mathlib.Data.Sign._hyg.6629 : α) (x._@.Mathlib.Data.Sign._hyg.6631 : α) => LT.lt.{u1} α (Preorder.toLT.{u1} α _inst_2) x._@.Mathlib.Data.Sign._hyg.6629 x._@.Mathlib.Data.Sign._hyg.6631)] (a : α), Eq.{1} SignType (OrderHom.toFun.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (DistribLattice.toLattice.{0} SignType (instDistribLattice.{0} SignType SignType.instLinearOrderSignType))))) (SignType.sign.{u1} α (NegZeroClass.toZero.{u1} α (SubNegZeroMonoid.toNegZeroClass.{u1} α (SubtractionMonoid.toSubNegZeroMonoid.{u1} α (AddGroup.toSubtractionMonoid.{u1} α _inst_1)))) _inst_2 (fun (a : α) (b : α) => _inst_3 a b)) (Neg.neg.{u1} α (NegZeroClass.toNeg.{u1} α (SubNegZeroMonoid.toNegZeroClass.{u1} α (SubtractionMonoid.toSubNegZeroMonoid.{u1} α (AddGroup.toSubtractionMonoid.{u1} α _inst_1)))) a)) (Neg.neg.{0} SignType SignType.instNegSignType (OrderHom.toFun.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (DistribLattice.toLattice.{0} SignType (instDistribLattice.{0} SignType SignType.instLinearOrderSignType))))) (SignType.sign.{u1} α (NegZeroClass.toZero.{u1} α (SubNegZeroMonoid.toNegZeroClass.{u1} α (SubtractionMonoid.toSubNegZeroMonoid.{u1} α (AddGroup.toSubtractionMonoid.{u1} α _inst_1)))) _inst_2 (fun (a : α) (b : α) => _inst_3 a b)) a))
+  forall {α : Type.{u1}} [_inst_1 : AddGroup.{u1} α] [_inst_2 : Preorder.{u1} α] [_inst_3 : DecidableRel.{succ u1} α (fun (x._@.Mathlib.Data.Sign._hyg.6598 : α) (x._@.Mathlib.Data.Sign._hyg.6600 : α) => LT.lt.{u1} α (Preorder.toLT.{u1} α _inst_2) x._@.Mathlib.Data.Sign._hyg.6598 x._@.Mathlib.Data.Sign._hyg.6600)] [_inst_4 : CovariantClass.{u1, u1} α α (Function.swap.{succ u1, succ u1, succ u1} α α (fun (ᾰ : α) (ᾰ : α) => α) (fun (x._@.Mathlib.Data.Sign._hyg.6620 : α) (x._@.Mathlib.Data.Sign._hyg.6622 : α) => HAdd.hAdd.{u1, u1, u1} α α α (instHAdd.{u1} α (AddZeroClass.toAdd.{u1} α (AddMonoid.toAddZeroClass.{u1} α (SubNegMonoid.toAddMonoid.{u1} α (AddGroup.toSubNegMonoid.{u1} α _inst_1))))) x._@.Mathlib.Data.Sign._hyg.6620 x._@.Mathlib.Data.Sign._hyg.6622)) (fun (x._@.Mathlib.Data.Sign._hyg.6635 : α) (x._@.Mathlib.Data.Sign._hyg.6637 : α) => LT.lt.{u1} α (Preorder.toLT.{u1} α _inst_2) x._@.Mathlib.Data.Sign._hyg.6635 x._@.Mathlib.Data.Sign._hyg.6637)] (a : α), Eq.{1} SignType (OrderHom.toFun.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (DistribLattice.toLattice.{0} SignType (instDistribLattice.{0} SignType SignType.instLinearOrderSignType))))) (SignType.sign.{u1} α (NegZeroClass.toZero.{u1} α (SubNegZeroMonoid.toNegZeroClass.{u1} α (SubtractionMonoid.toSubNegZeroMonoid.{u1} α (AddGroup.toSubtractionMonoid.{u1} α _inst_1)))) _inst_2 (fun (a : α) (b : α) => _inst_3 a b)) (Neg.neg.{u1} α (NegZeroClass.toNeg.{u1} α (SubNegZeroMonoid.toNegZeroClass.{u1} α (SubtractionMonoid.toSubNegZeroMonoid.{u1} α (AddGroup.toSubtractionMonoid.{u1} α _inst_1)))) a)) (Neg.neg.{0} SignType SignType.instNegSignType (OrderHom.toFun.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (DistribLattice.toLattice.{0} SignType (instDistribLattice.{0} SignType SignType.instLinearOrderSignType))))) (SignType.sign.{u1} α (NegZeroClass.toZero.{u1} α (SubNegZeroMonoid.toNegZeroClass.{u1} α (SubtractionMonoid.toSubNegZeroMonoid.{u1} α (AddGroup.toSubtractionMonoid.{u1} α _inst_1)))) _inst_2 (fun (a : α) (b : α) => _inst_3 a b)) a))
 Case conversion may be inaccurate. Consider using '#align right.sign_neg Right.sign_negₓ'. -/
 theorem Right.sign_neg [CovariantClass α α (Function.swap (· + ·)) (· < ·)] (a : α) :
     SignType.sign (-a) = -SignType.sign a :=

mathlib commit https://github.com/leanprover-community/mathlib/commit/9da1b3534b65d9661eb8f42443598a92bbb49211

@@ -552,7 +552,7 @@ variable [AddGroup α] [Preorder α] [DecidableRel ((· < ·) : α → α → Pr
 lean 3 declaration is
   forall {α : Type.{u1}} [_inst_1 : AddGroup.{u1} α] [_inst_2 : Preorder.{u1} α] [_inst_3 : DecidableRel.{succ u1} α (LT.lt.{u1} α (Preorder.toLT.{u1} α _inst_2))] [_inst_4 : CovariantClass.{u1, u1} α α (HAdd.hAdd.{u1, u1, u1} α α α (instHAdd.{u1} α (AddZeroClass.toHasAdd.{u1} α (AddMonoid.toAddZeroClass.{u1} α (SubNegMonoid.toAddMonoid.{u1} α (AddGroup.toSubNegMonoid.{u1} α _inst_1)))))) (LT.lt.{u1} α (Preorder.toLT.{u1} α _inst_2))] (a : α), Eq.{1} SignType (coeFn.{succ u1, succ u1} (OrderHom.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) (fun (_x : OrderHom.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) => α -> SignType) (OrderHom.hasCoeToFun.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) (SignType.sign.{u1} α (AddZeroClass.toHasZero.{u1} α (AddMonoid.toAddZeroClass.{u1} α (SubNegMonoid.toAddMonoid.{u1} α (AddGroup.toSubNegMonoid.{u1} α _inst_1)))) _inst_2 (fun (a : α) (b : α) => _inst_3 a b)) (Neg.neg.{u1} α (SubNegMonoid.toHasNeg.{u1} α (AddGroup.toSubNegMonoid.{u1} α _inst_1)) a)) (Neg.neg.{0} SignType SignType.hasNeg (coeFn.{succ u1, succ u1} (OrderHom.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) (fun (_x : OrderHom.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) => α -> SignType) (OrderHom.hasCoeToFun.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) (SignType.sign.{u1} α (AddZeroClass.toHasZero.{u1} α (AddMonoid.toAddZeroClass.{u1} α (SubNegMonoid.toAddMonoid.{u1} α (AddGroup.toSubNegMonoid.{u1} α _inst_1)))) _inst_2 (fun (a : α) (b : α) => _inst_3 a b)) a))
 but is expected to have type
-  forall {α : Type.{u1}} [_inst_1 : AddGroup.{u1} α] [_inst_2 : Preorder.{u1} α] [_inst_3 : DecidableRel.{succ u1} α (fun (x._@.Mathlib.Data.Sign._hyg.6253 : α) (x._@.Mathlib.Data.Sign._hyg.6255 : α) => LT.lt.{u1} α (Preorder.toLT.{u1} α _inst_2) x._@.Mathlib.Data.Sign._hyg.6253 x._@.Mathlib.Data.Sign._hyg.6255)] [_inst_4 : CovariantClass.{u1, u1} α α (fun (x._@.Mathlib.Data.Sign._hyg.6272 : α) (x._@.Mathlib.Data.Sign._hyg.6274 : α) => HAdd.hAdd.{u1, u1, u1} α α α (instHAdd.{u1} α (AddZeroClass.toAdd.{u1} α (AddMonoid.toAddZeroClass.{u1} α (SubNegMonoid.toAddMonoid.{u1} α (AddGroup.toSubNegMonoid.{u1} α _inst_1))))) x._@.Mathlib.Data.Sign._hyg.6272 x._@.Mathlib.Data.Sign._hyg.6274) (fun (x._@.Mathlib.Data.Sign._hyg.6287 : α) (x._@.Mathlib.Data.Sign._hyg.6289 : α) => LT.lt.{u1} α (Preorder.toLT.{u1} α _inst_2) x._@.Mathlib.Data.Sign._hyg.6287 x._@.Mathlib.Data.Sign._hyg.6289)] (a : α), Eq.{1} SignType (OrderHom.toFun.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (DistribLattice.toLattice.{0} SignType (instDistribLattice.{0} SignType SignType.instLinearOrderSignType))))) (SignType.sign.{u1} α (NegZeroClass.toZero.{u1} α (SubNegZeroMonoid.toNegZeroClass.{u1} α (SubtractionMonoid.toSubNegZeroMonoid.{u1} α (AddGroup.toSubtractionMonoid.{u1} α _inst_1)))) _inst_2 (fun (a : α) (b : α) => _inst_3 a b)) (Neg.neg.{u1} α (NegZeroClass.toNeg.{u1} α (SubNegZeroMonoid.toNegZeroClass.{u1} α (SubtractionMonoid.toSubNegZeroMonoid.{u1} α (AddGroup.toSubtractionMonoid.{u1} α _inst_1)))) a)) (Neg.neg.{0} SignType SignType.instNegSignType (OrderHom.toFun.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (DistribLattice.toLattice.{0} SignType (instDistribLattice.{0} SignType SignType.instLinearOrderSignType))))) (SignType.sign.{u1} α (NegZeroClass.toZero.{u1} α (SubNegZeroMonoid.toNegZeroClass.{u1} α (SubtractionMonoid.toSubNegZeroMonoid.{u1} α (AddGroup.toSubtractionMonoid.{u1} α _inst_1)))) _inst_2 (fun (a : α) (b : α) => _inst_3 a b)) a))
+  forall {α : Type.{u1}} [_inst_1 : AddGroup.{u1} α] [_inst_2 : Preorder.{u1} α] [_inst_3 : DecidableRel.{succ u1} α (fun (x._@.Mathlib.Data.Sign._hyg.6474 : α) (x._@.Mathlib.Data.Sign._hyg.6476 : α) => LT.lt.{u1} α (Preorder.toLT.{u1} α _inst_2) x._@.Mathlib.Data.Sign._hyg.6474 x._@.Mathlib.Data.Sign._hyg.6476)] [_inst_4 : CovariantClass.{u1, u1} α α (fun (x._@.Mathlib.Data.Sign._hyg.6493 : α) (x._@.Mathlib.Data.Sign._hyg.6495 : α) => HAdd.hAdd.{u1, u1, u1} α α α (instHAdd.{u1} α (AddZeroClass.toAdd.{u1} α (AddMonoid.toAddZeroClass.{u1} α (SubNegMonoid.toAddMonoid.{u1} α (AddGroup.toSubNegMonoid.{u1} α _inst_1))))) x._@.Mathlib.Data.Sign._hyg.6493 x._@.Mathlib.Data.Sign._hyg.6495) (fun (x._@.Mathlib.Data.Sign._hyg.6508 : α) (x._@.Mathlib.Data.Sign._hyg.6510 : α) => LT.lt.{u1} α (Preorder.toLT.{u1} α _inst_2) x._@.Mathlib.Data.Sign._hyg.6508 x._@.Mathlib.Data.Sign._hyg.6510)] (a : α), Eq.{1} SignType (OrderHom.toFun.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (DistribLattice.toLattice.{0} SignType (instDistribLattice.{0} SignType SignType.instLinearOrderSignType))))) (SignType.sign.{u1} α (NegZeroClass.toZero.{u1} α (SubNegZeroMonoid.toNegZeroClass.{u1} α (SubtractionMonoid.toSubNegZeroMonoid.{u1} α (AddGroup.toSubtractionMonoid.{u1} α _inst_1)))) _inst_2 (fun (a : α) (b : α) => _inst_3 a b)) (Neg.neg.{u1} α (NegZeroClass.toNeg.{u1} α (SubNegZeroMonoid.toNegZeroClass.{u1} α (SubtractionMonoid.toSubNegZeroMonoid.{u1} α (AddGroup.toSubtractionMonoid.{u1} α _inst_1)))) a)) (Neg.neg.{0} SignType SignType.instNegSignType (OrderHom.toFun.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (DistribLattice.toLattice.{0} SignType (instDistribLattice.{0} SignType SignType.instLinearOrderSignType))))) (SignType.sign.{u1} α (NegZeroClass.toZero.{u1} α (SubNegZeroMonoid.toNegZeroClass.{u1} α (SubtractionMonoid.toSubNegZeroMonoid.{u1} α (AddGroup.toSubtractionMonoid.{u1} α _inst_1)))) _inst_2 (fun (a : α) (b : α) => _inst_3 a b)) a))
 Case conversion may be inaccurate. Consider using '#align left.sign_neg Left.sign_negₓ'. -/
 theorem Left.sign_neg [CovariantClass α α (· + ·) (· < ·)] (a : α) :
     SignType.sign (-a) = -SignType.sign a :=
@@ -569,7 +569,7 @@ theorem Left.sign_neg [CovariantClass α α (· + ·) (· < ·)] (a : α) :
 lean 3 declaration is
   forall {α : Type.{u1}} [_inst_1 : AddGroup.{u1} α] [_inst_2 : Preorder.{u1} α] [_inst_3 : DecidableRel.{succ u1} α (LT.lt.{u1} α (Preorder.toLT.{u1} α _inst_2))] [_inst_4 : CovariantClass.{u1, u1} α α (Function.swap.{succ u1, succ u1, succ u1} α α (fun (ᾰ : α) (ᾰ : α) => α) (HAdd.hAdd.{u1, u1, u1} α α α (instHAdd.{u1} α (AddZeroClass.toHasAdd.{u1} α (AddMonoid.toAddZeroClass.{u1} α (SubNegMonoid.toAddMonoid.{u1} α (AddGroup.toSubNegMonoid.{u1} α _inst_1))))))) (LT.lt.{u1} α (Preorder.toLT.{u1} α _inst_2))] (a : α), Eq.{1} SignType (coeFn.{succ u1, succ u1} (OrderHom.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) (fun (_x : OrderHom.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) => α -> SignType) (OrderHom.hasCoeToFun.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) (SignType.sign.{u1} α (AddZeroClass.toHasZero.{u1} α (AddMonoid.toAddZeroClass.{u1} α (SubNegMonoid.toAddMonoid.{u1} α (AddGroup.toSubNegMonoid.{u1} α _inst_1)))) _inst_2 (fun (a : α) (b : α) => _inst_3 a b)) (Neg.neg.{u1} α (SubNegMonoid.toHasNeg.{u1} α (AddGroup.toSubNegMonoid.{u1} α _inst_1)) a)) (Neg.neg.{0} SignType SignType.hasNeg (coeFn.{succ u1, succ u1} (OrderHom.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) (fun (_x : OrderHom.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) => α -> SignType) (OrderHom.hasCoeToFun.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (LinearOrder.toLattice.{0} SignType SignType.linearOrder))))) (SignType.sign.{u1} α (AddZeroClass.toHasZero.{u1} α (AddMonoid.toAddZeroClass.{u1} α (SubNegMonoid.toAddMonoid.{u1} α (AddGroup.toSubNegMonoid.{u1} α _inst_1)))) _inst_2 (fun (a : α) (b : α) => _inst_3 a b)) a))
 but is expected to have type
-  forall {α : Type.{u1}} [_inst_1 : AddGroup.{u1} α] [_inst_2 : Preorder.{u1} α] [_inst_3 : DecidableRel.{succ u1} α (fun (x._@.Mathlib.Data.Sign._hyg.6371 : α) (x._@.Mathlib.Data.Sign._hyg.6373 : α) => LT.lt.{u1} α (Preorder.toLT.{u1} α _inst_2) x._@.Mathlib.Data.Sign._hyg.6371 x._@.Mathlib.Data.Sign._hyg.6373)] [_inst_4 : CovariantClass.{u1, u1} α α (Function.swap.{succ u1, succ u1, succ u1} α α (fun (ᾰ : α) (ᾰ : α) => α) (fun (x._@.Mathlib.Data.Sign._hyg.6393 : α) (x._@.Mathlib.Data.Sign._hyg.6395 : α) => HAdd.hAdd.{u1, u1, u1} α α α (instHAdd.{u1} α (AddZeroClass.toAdd.{u1} α (AddMonoid.toAddZeroClass.{u1} α (SubNegMonoid.toAddMonoid.{u1} α (AddGroup.toSubNegMonoid.{u1} α _inst_1))))) x._@.Mathlib.Data.Sign._hyg.6393 x._@.Mathlib.Data.Sign._hyg.6395)) (fun (x._@.Mathlib.Data.Sign._hyg.6408 : α) (x._@.Mathlib.Data.Sign._hyg.6410 : α) => LT.lt.{u1} α (Preorder.toLT.{u1} α _inst_2) x._@.Mathlib.Data.Sign._hyg.6408 x._@.Mathlib.Data.Sign._hyg.6410)] (a : α), Eq.{1} SignType (OrderHom.toFun.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (DistribLattice.toLattice.{0} SignType (instDistribLattice.{0} SignType SignType.instLinearOrderSignType))))) (SignType.sign.{u1} α (NegZeroClass.toZero.{u1} α (SubNegZeroMonoid.toNegZeroClass.{u1} α (SubtractionMonoid.toSubNegZeroMonoid.{u1} α (AddGroup.toSubtractionMonoid.{u1} α _inst_1)))) _inst_2 (fun (a : α) (b : α) => _inst_3 a b)) (Neg.neg.{u1} α (NegZeroClass.toNeg.{u1} α (SubNegZeroMonoid.toNegZeroClass.{u1} α (SubtractionMonoid.toSubNegZeroMonoid.{u1} α (AddGroup.toSubtractionMonoid.{u1} α _inst_1)))) a)) (Neg.neg.{0} SignType SignType.instNegSignType (OrderHom.toFun.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (DistribLattice.toLattice.{0} SignType (instDistribLattice.{0} SignType SignType.instLinearOrderSignType))))) (SignType.sign.{u1} α (NegZeroClass.toZero.{u1} α (SubNegZeroMonoid.toNegZeroClass.{u1} α (SubtractionMonoid.toSubNegZeroMonoid.{u1} α (AddGroup.toSubtractionMonoid.{u1} α _inst_1)))) _inst_2 (fun (a : α) (b : α) => _inst_3 a b)) a))
+  forall {α : Type.{u1}} [_inst_1 : AddGroup.{u1} α] [_inst_2 : Preorder.{u1} α] [_inst_3 : DecidableRel.{succ u1} α (fun (x._@.Mathlib.Data.Sign._hyg.6592 : α) (x._@.Mathlib.Data.Sign._hyg.6594 : α) => LT.lt.{u1} α (Preorder.toLT.{u1} α _inst_2) x._@.Mathlib.Data.Sign._hyg.6592 x._@.Mathlib.Data.Sign._hyg.6594)] [_inst_4 : CovariantClass.{u1, u1} α α (Function.swap.{succ u1, succ u1, succ u1} α α (fun (ᾰ : α) (ᾰ : α) => α) (fun (x._@.Mathlib.Data.Sign._hyg.6614 : α) (x._@.Mathlib.Data.Sign._hyg.6616 : α) => HAdd.hAdd.{u1, u1, u1} α α α (instHAdd.{u1} α (AddZeroClass.toAdd.{u1} α (AddMonoid.toAddZeroClass.{u1} α (SubNegMonoid.toAddMonoid.{u1} α (AddGroup.toSubNegMonoid.{u1} α _inst_1))))) x._@.Mathlib.Data.Sign._hyg.6614 x._@.Mathlib.Data.Sign._hyg.6616)) (fun (x._@.Mathlib.Data.Sign._hyg.6629 : α) (x._@.Mathlib.Data.Sign._hyg.6631 : α) => LT.lt.{u1} α (Preorder.toLT.{u1} α _inst_2) x._@.Mathlib.Data.Sign._hyg.6629 x._@.Mathlib.Data.Sign._hyg.6631)] (a : α), Eq.{1} SignType (OrderHom.toFun.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (DistribLattice.toLattice.{0} SignType (instDistribLattice.{0} SignType SignType.instLinearOrderSignType))))) (SignType.sign.{u1} α (NegZeroClass.toZero.{u1} α (SubNegZeroMonoid.toNegZeroClass.{u1} α (SubtractionMonoid.toSubNegZeroMonoid.{u1} α (AddGroup.toSubtractionMonoid.{u1} α _inst_1)))) _inst_2 (fun (a : α) (b : α) => _inst_3 a b)) (Neg.neg.{u1} α (NegZeroClass.toNeg.{u1} α (SubNegZeroMonoid.toNegZeroClass.{u1} α (SubtractionMonoid.toSubNegZeroMonoid.{u1} α (AddGroup.toSubtractionMonoid.{u1} α _inst_1)))) a)) (Neg.neg.{0} SignType SignType.instNegSignType (OrderHom.toFun.{u1, 0} α SignType _inst_2 (PartialOrder.toPreorder.{0} SignType (SemilatticeInf.toPartialOrder.{0} SignType (Lattice.toSemilatticeInf.{0} SignType (DistribLattice.toLattice.{0} SignType (instDistribLattice.{0} SignType SignType.instLinearOrderSignType))))) (SignType.sign.{u1} α (NegZeroClass.toZero.{u1} α (SubNegZeroMonoid.toNegZeroClass.{u1} α (SubtractionMonoid.toSubNegZeroMonoid.{u1} α (AddGroup.toSubtractionMonoid.{u1} α _inst_1)))) _inst_2 (fun (a : α) (b : α) => _inst_3 a b)) a))
 Case conversion may be inaccurate. Consider using '#align right.sign_neg Right.sign_negₓ'. -/
 theorem Right.sign_neg [CovariantClass α α (Function.swap (· + ·)) (· < ·)] (a : α) :
     SignType.sign (-a) = -SignType.sign a :=

mathlib commit https://github.com/leanprover-community/mathlib/commit/bd9851ca476957ea4549eb19b40e7b5ade9428cc

These · are scoping when there is a single active goal.

These were found using a modification of the linter at #12339.

@@ -361,7 +361,7 @@ theorem sign_eq_neg_one_iff : sign a = -1 ↔ a < 0 := by
   refine' ⟨fun h => _, fun h => sign_neg h⟩
   rw [sign_apply] at h
   split_ifs at h
-  · assumption
+  assumption
 #align sign_eq_neg_one_iff sign_eq_neg_one_iff
 
 end Preorder

See also #7842

@@ -146,14 +146,12 @@ def fin3Equiv : SignType ≃* Fin 3 where
     | ⟨0, _⟩ => 0
     | ⟨1, _⟩ => 1
     | ⟨2, _⟩ => -1
-    | ⟨n + 3, h⟩ => (h.not_le le_add_self).elim
   left_inv a := by cases a <;> rfl
   right_inv a :=
     match a with
     | ⟨0, _⟩ => by simp
     | ⟨1, _⟩ => by simp
     | ⟨2, _⟩ => by simp
-    | ⟨n + 3, h⟩ => by simp at h
   map_mul' a b := by
     cases a <;> cases b <;> rfl
 #align sign_type.fin3_equiv SignType.fin3Equiv
@@ -430,16 +428,18 @@ theorem sign_mul (x y : α) : sign (x * y) = sign x * sign y := by
 #align sign_mul sign_mul
 
 @[simp] theorem sign_mul_abs (x : α) : (sign x * |x| : α) = x := by
-  rcases lt_trichotomy x 0 with (hx | rfl | hx)
-  · rw [sign_neg hx, abs_of_neg hx, coe_neg_one, neg_one_mul, neg_neg]
-  · rw [abs_zero, mul_zero]
-  · rw [sign_pos hx, abs_of_pos hx, coe_one, one_mul]
+  rcases lt_trichotomy x 0 with hx | rfl | hx <;> simp [*, abs_of_pos, abs_of_neg]
 
 @[simp] theorem abs_mul_sign (x : α) : (|x| * sign x : α) = x := by
-  rcases lt_trichotomy x 0 with (hx | rfl | hx)
-  · rw [sign_neg hx, abs_of_neg hx, coe_neg_one, mul_neg_one, neg_neg]
-  · rw [abs_zero, zero_mul]
-  · rw [sign_pos hx, abs_of_pos hx, coe_one, mul_one]
+  rcases lt_trichotomy x 0 with hx | rfl | hx <;> simp [*, abs_of_pos, abs_of_neg]
+
+@[simp]
+theorem sign_mul_self (x : α) : sign x * x = |x| := by
+  rcases lt_trichotomy x 0 with hx | rfl | hx <;> simp [*, abs_of_pos, abs_of_neg]
+
+@[simp]
+theorem self_mul_sign (x : α) : x * sign x = |x| := by
+  rcases lt_trichotomy x 0 with hx | rfl | hx <;> simp [*, abs_of_pos, abs_of_neg]
 
 /-- `SignType.sign` as a `MonoidWithZeroHom` for a nontrivial ordered semiring. Note that linearity
 is required; consider ℂ with the order `z ≤ w` iff they have the same imaginary part and

Take the content of

• some of Algebra.BigOperators.List.Basic
• some of Algebra.BigOperators.List.Lemmas
• some of Algebra.BigOperators.Multiset.Basic
• some of Algebra.BigOperators.Multiset.Lemmas
• Algebra.BigOperators.Multiset.Order
• Algebra.BigOperators.Order

and sort it into six files:

• Algebra.Order.BigOperators.Group.List. I credit Yakov for https://github.com/leanprover-community/mathlib/pull/8543.
• Algebra.Order.BigOperators.Group.Multiset. Copyright inherited from Algebra.BigOperators.Multiset.Order.
• Algebra.Order.BigOperators.Group.Finset. Copyright inherited from Algebra.BigOperators.Order.
• Algebra.Order.BigOperators.Ring.List. I credit Stuart for https://github.com/leanprover-community/mathlib/pull/10184.
• Algebra.Order.BigOperators.Ring.Multiset. I credit Ruben for https://github.com/leanprover-community/mathlib/pull/8787.
• Algebra.Order.BigOperators.Ring.Finset. I credit Floris for https://github.com/leanprover-community/mathlib/pull/1294.

Here are the design decisions at play:

• Pure algebra and big operators algebra shouldn't import (algebraic) order theory. This PR makes that better, but not perfect because we still import Data.Nat.Order.Basic in a few List files.
• It's Algebra.Order.BigOperators instead of Algebra.BigOperators.Order because algebraic order theory is more of a theory than big operators algebra. Another reason is that algebraic order theory is the only way to mix pure order and pure algebra, while there are more ways to mix pure finiteness and pure algebra than just big operators.
• There are separate files for group/monoid lemmas vs ring lemmas. Groups/monoids are the natural setup for big operators, so their lemmas shouldn't be mixed with ring lemmas that involves both addition and multiplication. As a result, everything under Algebra.Order.BigOperators.Group should be additivisable (except a few Nat- or Int-specific lemmas). In contrast, things under Algebra.Order.BigOperators.Ring are more prone to having heavy imports.
• Lemmas are separated according to List vs Multiset vs Finset. This is not strictly necessary, and can be relaxed in cases where there aren't that many lemmas to be had. As an example, I could split out the AbsoluteValue lemmas from Algebra.Order.BigOperators.Ring.Finset to a file Algebra.Order.BigOperators.Ring.AbsoluteValue and it could stay this way until too many lemmas are in this file (or a split is needed for import reasons), in which case we would need files Algebra.Order.BigOperators.Ring.AbsoluteValue.Finset, Algebra.Order.BigOperators.Ring.AbsoluteValue.Multiset, etc...
• Finsupp big operator and finprod/finsum order lemmas also belong in Algebra.Order.BigOperators. I haven't done so in this PR because the diff is big enough like that.

@@ -3,7 +3,8 @@ Copyright (c) 2022 Eric Rodriguez. All rights reserved.
 Released under Apache 2.0 license as described in the file LICENSE.
 Authors: Eric Rodriguez
 -/
-import Mathlib.Algebra.BigOperators.Order
+import Mathlib.Algebra.GroupWithZero.Units.Lemmas
+import Mathlib.Algebra.Order.BigOperators.Group.Finset
 import Mathlib.Data.Fintype.BigOperators
 
 #align_import data.sign from "leanprover-community/mathlib"@"2445c98ae4b87eabebdde552593519b9b6dc350c"

Classifies by adding issue number #10756 to porting notes claiming anything equivalent to:

• "added theorem"
• "added theorems"
• "new theorem"
• "new theorems"
• "added lemma"
• "new lemma"
• "new lemmas"

@@ -293,7 +293,7 @@ def castHom {α} [MulZeroOneClass α] [HasDistribNeg α] : SignType →*₀ α w
   map_mul' x y := by cases x <;> cases y <;> simp [zero_eq_zero, pos_eq_one, neg_eq_neg_one]
 #align sign_type.cast_hom SignType.castHom
 
--- Porting note: new theorem
+-- Porting note (#10756): new theorem
 theorem univ_eq : (Finset.univ : Finset SignType) = {0, -1, 1} := by
   decide
 

Homogenises porting notes via capitalisation and addition of whitespace.

It makes the following changes:

• converts "--porting note" into "-- Porting note";
• converts "porting note" into "Porting note".

@@ -293,7 +293,7 @@ def castHom {α} [MulZeroOneClass α] [HasDistribNeg α] : SignType →*₀ α w
   map_mul' x y := by cases x <;> cases y <;> simp [zero_eq_zero, pos_eq_one, neg_eq_neg_one]
 #align sign_type.cast_hom SignType.castHom
 
---Porting note: new theorem
+-- Porting note: new theorem
 theorem univ_eq : (Finset.univ : Finset SignType) = {0, -1, 1} := by
   decide
 

Classifies by adding issue number #11081 to porting notes claiming:

cannot automatically derive

@@ -14,7 +14,7 @@ This file defines the sign function for types with zero and a decidable less-tha
 proves some basic theorems about it.
 -/
 
--- Porting note: Cannot automatically derive Fintype, added manually
+-- Porting note (#11081): cannot automatically derive Fintype, added manually
 /-- The type of signs. -/
 inductive SignType
   | zero

Since Real.sign etc are being deprecated in favour of the generic SignType.sign, this PR adds some more API for the latter: in particular, compatibility of the canonical maps in and out of SignType with maps satisfying suitable assumptions. This is a prerequisite for #10011.

@@ -250,6 +250,18 @@ instance : CoeTC SignType α :=
 
 -- Porting note: `cast_eq_coe` removed, syntactic equality
 
+/-- Casting out of `SignType` respects composition with functions preserving `0, 1, -1`. -/
+lemma map_cast' {β : Type*} [One β] [Neg β] [Zero β]
+    (f : α → β) (h₁ : f 1 = 1) (h₂ : f 0 = 0) (h₃ : f (-1) = -1) (s : SignType) :
+    f s = s := by
+  cases s <;> simp only [SignType.cast, h₁, h₂, h₃]
+
+/-- Casting out of `SignType` respects composition with suitable bundled homomorphism types. -/
+lemma map_cast {α β F : Type*} [AddGroupWithOne α] [One β] [SubtractionMonoid β]
+    [FunLike F α β] [AddMonoidHomClass F α β] [OneHomClass F α β] (f : F) (s : SignType) :
+    f s = s := by
+  apply map_cast' <;> simp
+
 @[simp]
 theorem coe_zero : ↑(0 : SignType) = (0 : α) :=
   rfl
@@ -265,6 +277,11 @@ theorem coe_neg_one : ↑(-1 : SignType) = (-1 : α) :=
   rfl
 #align sign_type.coe_neg_one SignType.coe_neg_one
 
+@[simp, norm_cast]
+lemma coe_neg {α : Type*} [One α] [SubtractionMonoid α] (s : SignType) :
+    (↑(-s) : α) = -↑s := by
+  cases s <;> simp
+
 end cast
 
 /-- `SignType.cast` as a `MulWithZeroHom`. -/
@@ -354,6 +371,12 @@ section LinearOrder
 
 variable [Zero α] [LinearOrder α] {a : α}
 
+/-- `SignType.sign` respects strictly monotone zero-preserving maps. -/
+lemma StrictMono.sign_comp {β F : Type*} [Zero β] [Preorder β] [DecidableRel ((· < ·) : β → β → _)]
+    [FunLike F α β] [ZeroHomClass F α β] {f : F} (hf : StrictMono f) (a : α) :
+    sign (f a) = sign a := by
+  simp only [sign_apply, ← map_zero f, hf.lt_iff_lt]
+
 @[simp]
 theorem sign_eq_zero_iff : sign a = 0 ↔ a = 0 := by
   refine' ⟨fun h => _, fun h => h.symm ▸ sign_zero⟩

Classify by adding issue number (#10618) to porting notes claiming anything semantically equivalent to simp can prove this or simp can simplify this.

@@ -389,7 +389,7 @@ section OrderedSemiring
 
 variable [OrderedSemiring α] [DecidableRel ((· < ·) : α → α → Prop)] [Nontrivial α]
 
--- @[simp] -- Porting note: simp can prove this
+-- @[simp] -- Porting note (#10618): simp can prove this
 theorem sign_one : sign (1 : α) = 1 :=
   sign_pos zero_lt_one
 #align sign_one sign_one

Co-authored-by: Scott Morrison <scott.morrison@gmail.com>

@@ -111,7 +111,7 @@ private lemma le_antisymm (a b : SignType) (_ : a ≤ b) (_: b ≤ a) : a = b :=
   cases a <;> cases b <;> trivial
 
 private lemma le_trans (a b c : SignType) (_ : a ≤ b) (_: b ≤ c) : a ≤ c := by
-  cases a <;> cases b <;> cases c <;> first | tauto | constructor
+  cases a <;> cases b <;> cases c <;> tauto
 
 instance : LinearOrder SignType where
   le := (· ≤ ·)

This uses the improved shake script from #9772 to reduce imports across mathlib. The corresponding noshake.json file has been added to #9772.

Co-authored-by: Mario Carneiro <di.gama@gmail.com>

@@ -5,7 +5,6 @@ Authors: Eric Rodriguez
 -/
 import Mathlib.Algebra.BigOperators.Order
 import Mathlib.Data.Fintype.BigOperators
-import Mathlib.Data.Int.Lemmas
 
 #align_import data.sign from "leanprover-community/mathlib"@"2445c98ae4b87eabebdde552593519b9b6dc350c"
 /-!

Lemmas around this were a mess, throth in terms of names, statement and location. This PR standardises everything to be in Algebra.BigOperators.Basic and changes the lemmas to take in InjOn and SurjOn assumptions where possible (and where impossible make sure the hypotheses are taken in the correct order) and moves the equality of functions hypothesis last.

Also add a few lemmas that help fix downstream uses by golfing.

From LeanAPAP and LeanCamCombi

@@ -518,7 +518,7 @@ theorem exists_signed_sum {α : Type u_1} [DecidableEq α] (s : Finset α) (f :
           ∀ a ∈ s, (∑ b, if g b = a then (sgn b : ℤ) else 0) = f a :=
   let ⟨β, t, sgn, g, hg, ht, hf⟩ := exists_signed_sum_aux s f
   ⟨t, inferInstance, fun b => sgn b, fun b => g b, fun b => hg b, by simp [ht], fun a ha =>
-    (@sum_attach _ _ t _ fun b => ite (g b = a) (sgn b : ℤ) 0).trans <| hf _ ha⟩
+    (sum_attach t fun b ↦ ite (g b = a) (sgn b : ℤ) 0).trans <| hf _ ha⟩
 #align exists_signed_sum exists_signed_sum
 
 /-- We can decompose a sum of absolute value less than `n` into a sum of at most `n` signs. -/

This adds three simp and norm_cast lemmas for SignType.

@@ -286,6 +286,18 @@ theorem range_eq {α} (f : SignType → α) : Set.range f = {f zero, f neg, f po
   classical simp [Finset.coe_insert]
 #align sign_type.range_eq SignType.range_eq
 
+@[simp, norm_cast] lemma coe_mul {α} [MulZeroOneClass α] [HasDistribNeg α] (a b : SignType) :
+    ↑(a * b) = (a : α) * b :=
+  map_mul SignType.castHom _ _
+
+@[simp, norm_cast] lemma coe_pow {α} [MonoidWithZero α] [HasDistribNeg α] (a : SignType) (k : ℕ) :
+    ↑(a ^ k) = (a : α) ^ k :=
+  map_pow SignType.castHom _ _
+
+@[simp, norm_cast] lemma coe_zpow {α} [GroupWithZero α] [HasDistribNeg α] (a : SignType) (k : ℤ) :
+    ↑(a ^ k) = (a : α) ^ k :=
+  map_zpow₀ SignType.castHom _ _
+
 end SignType
 
 variable {α : Type*}
@@ -389,10 +401,6 @@ section LinearOrderedRing
 
 variable [LinearOrderedRing α] {a b : α}
 
-/- I'm not sure why this is necessary, see https://leanprover.zulipchat.com/#narrow/stream/
-113488-general/topic/type.20class.20inference.20issues/near/276937942 -/
-attribute [local instance] LinearOrderedRing.decidableLT
-
 theorem sign_mul (x y : α) : sign (x * y) = sign x * sign y := by
   rcases lt_trichotomy x 0 with (hx | hx | hx) <;> rcases lt_trichotomy y 0 with (hy | hy | hy) <;>
     simp [hx, hy, mul_pos_of_neg_of_neg, mul_neg_of_neg_of_pos, mul_neg_of_pos_of_neg]

@@ -34,7 +34,7 @@ namespace SignType
 
 -- Porting note: Added Fintype SignType manually
 instance : Fintype SignType :=
-   Fintype.ofMultiset (zero :: neg :: pos :: List.nil) (fun x ↦ by cases x <;> decide)
+   Fintype.ofMultiset (zero :: neg :: pos :: List.nil) (fun x ↦ by cases x <;> simp)
 
 instance : Zero SignType :=
   ⟨zero⟩

Co-authored-by: Moritz Firsching <firsching@google.com>

@@ -360,7 +360,7 @@ theorem sign_ne_zero : sign a ≠ 0 ↔ a ≠ 0 :=
 theorem sign_nonneg_iff : 0 ≤ sign a ↔ 0 ≤ a := by
   rcases lt_trichotomy 0 a with (h | h | h)
   · simp [h, h.le]
-  · simp [←h]
+  · simp [← h]
   · simp [h, h.not_le]
 #align sign_nonneg_iff sign_nonneg_iff
 
@@ -368,7 +368,7 @@ theorem sign_nonneg_iff : 0 ≤ sign a ↔ 0 ≤ a := by
 theorem sign_nonpos_iff : sign a ≤ 0 ↔ a ≤ 0 := by
   rcases lt_trichotomy 0 a with (h | h | h)
   · simp [h, h.not_le]
-  · simp [←h]
+  · simp [← h]
   · simp [h, h.le]
 #align sign_nonpos_iff sign_nonpos_iff
 

PR contents

This is the supremum of

• #8284
• #8056
• #8023
• #8332
• #8226 (already approved)
• #7834 (already approved)

along with some minor fixes from failures on nightly-testing as Mathlib master is merged into it.

Note that some PRs for changes that are already compatible with the current toolchain and will be necessary have already been split out: #8380.

I am hopeful that in future we will be able to progressively merge adaptation PRs into a bump/v4.X.0 branch, so we never end up with a "big merge" like this. However one of these adaptation PRs (#8056) predates my new scheme for combined CI, and it wasn't possible to keep that PR viable in the meantime.

Lean PRs involved in this bump

In particular this includes adjustments for the Lean PRs

• leanprover/lean4#2778
• leanprover/lean4#2790
• leanprover/lean4#2783
• leanprover/lean4#2825
• leanprover/lean4#2722

leanprover/lean4#2778

We can get rid of all the

local macro_rules | `($x ^ $y) => `(HPow.hPow $x $y) -- Porting note: See issue [lean4#2220](https://github.com/leanprover/lean4/pull/2220)

macros across Mathlib (and in any projects that want to write natural number powers of reals).

leanprover/lean4#2722

Changes the default behaviour of simp to (config := {decide := false}). This makes simp (and consequentially norm_num) less powerful, but also more consistent, and less likely to blow up in long failures. This requires a variety of changes: changing some previously by simp or norm_num to decide or rfl, or adding (config := {decide := true}).

leanprover/lean4#2783

This changed the behaviour of simp so that simp [f] will only unfold "fully applied" occurrences of f. The old behaviour can be recovered with simp (config := { unfoldPartialApp := true }). We may in future add a syntax for this, e.g. simp [!f]; please provide feedback! In the meantime, we have made the following changes:

• switching to using explicit lemmas that have the intended level of application
• (config := { unfoldPartialApp := true }) in some places, to recover the old behaviour
• Using @[eqns] to manually adjust the equation lemmas for a particular definition, recovering the old behaviour just for that definition. See #8371, where we do this for Function.comp and Function.flip.

This change in Lean may require further changes down the line (e.g. adding the !f syntax, and/or upstreaming the special treatment for Function.comp and Function.flip, and/or removing this special treatment). Please keep an open and skeptical mind about these changes!

Co-authored-by: leanprover-community-mathlib4-bot <leanprover-community-mathlib4-bot@users.noreply.github.com> Co-authored-by: Scott Morrison <scott.morrison@gmail.com> Co-authored-by: Eric Wieser <wieser.eric@gmail.com> Co-authored-by: Mauricio Collares <mauricio@collares.org>

@@ -34,7 +34,7 @@ namespace SignType
 
 -- Porting note: Added Fintype SignType manually
 instance : Fintype SignType :=
-   Fintype.ofMultiset (zero :: neg :: pos :: List.nil) (fun x ↦ by cases x <;> simp only)
+   Fintype.ofMultiset (zero :: neg :: pos :: List.nil) (fun x ↦ by cases x <;> decide)
 
 instance : Zero SignType :=
   ⟨zero⟩
@@ -155,7 +155,7 @@ def fin3Equiv : SignType ≃* Fin 3 where
     | ⟨2, _⟩ => by simp
     | ⟨n + 3, h⟩ => by simp at h
   map_mul' a b := by
-    cases a <;> cases b <;> simp
+    cases a <;> cases b <;> rfl
 #align sign_type.fin3_equiv SignType.fin3Equiv
 
 section CaseBashing

Co-authored-by: Moritz Firsching <firsching@google.com>

@@ -515,7 +515,7 @@ theorem exists_signed_sum {α : Type u_1} [DecidableEq α] (s : Finset α) (f :
 
 /-- We can decompose a sum of absolute value less than `n` into a sum of at most `n` signs. -/
 theorem exists_signed_sum' {α : Type u_1} [Nonempty α] [DecidableEq α] (s : Finset α) (f : α → ℤ)
-  (n : ℕ) (h : (∑ i in s, (f i).natAbs) ≤ n) :
+    (n : ℕ) (h : (∑ i in s, (f i).natAbs) ≤ n) :
     ∃ (β : Type u_1) (_ : Fintype β) (sgn : β → SignType) (g : β → α),
       (∀ b, g b ∉ s → sgn b = 0) ∧
         Fintype.card β = n ∧ ∀ a ∈ s, (∑ i, if g i = a then (sgn i : ℤ) else 0) = f a := by

We remove all possible occurences of Type _ and Sort _ in favor of Type* and Sort*.

This has nice performance benefits.

@@ -234,7 +234,7 @@ end CaseBashing
 
 section cast
 
-variable {α : Type _} [Zero α] [One α] [Neg α]
+variable {α : Type*} [Zero α] [One α] [Neg α]
 
 /-- Turn a `SignType` into zero, one, or minus one. This is a coercion instance, but note it is
 only a `CoeTC` instance: see note [use has_coe_t]. -/
@@ -288,7 +288,7 @@ theorem range_eq {α} (f : SignType → α) : Set.range f = {f zero, f neg, f po
 
 end SignType
 
-variable {α : Type _}
+variable {α : Type*}
 
 open SignType
 
@@ -462,7 +462,7 @@ https://leanprover.zulipchat.com/#narrow/stream/113488-general/topic/Decidable.2
 -/
 attribute [local instance] LinearOrderedAddCommGroup.decidableLT
 
-theorem sign_sum {ι : Type _} {s : Finset ι} {f : ι → α} (hs : s.Nonempty) (t : SignType)
+theorem sign_sum {ι : Type*} {s : Finset ι} {f : ι → α} (hs : s.Nonempty) (t : SignType)
     (h : ∀ i ∈ s, sign (f i) = t) : sign (∑ i in s, f i) = t := by
   cases t
   · simp_rw [zero_eq_zero, sign_eq_zero_iff] at h ⊢

@@ -71,17 +71,17 @@ instance : Mul SignType :=
     | zero => zero
     | pos => y⟩
 
-/-- The less-than relation on signs. -/
-inductive Le : SignType → SignType → Prop
-  | of_neg (a) : Le neg a
-  | zero : Le zero zero
-  | of_pos (a) : Le a pos
-#align sign_type.le SignType.Le
+/-- The less-than-or-equal relation on signs. -/
+protected inductive LE : SignType → SignType → Prop
+  | of_neg (a) : SignType.LE neg a
+  | zero : SignType.LE zero zero
+  | of_pos (a) : SignType.LE a pos
+#align sign_type.le SignType.LE
 
 instance : LE SignType :=
-  ⟨Le⟩
+  ⟨SignType.LE⟩
 
-instance Le.decidableRel : DecidableRel Le := fun a b => by
+instance LE.decidableRel : DecidableRel SignType.LE := fun a b => by
   cases a <;> cases b <;> first | exact isTrue (by constructor)| exact isFalse (by rintro ⟨_⟩)
 
 instance decidableEq : DecidableEq SignType := fun a b => by
@@ -120,14 +120,14 @@ instance : LinearOrder SignType where
   le_total a b := by cases a <;> cases b <;> first | left; constructor | right; constructor
   le_antisymm := le_antisymm
   le_trans := le_trans
-  decidableLE := Le.decidableRel
+  decidableLE := LE.decidableRel
   decidableEq := SignType.decidableEq
 
 instance : BoundedOrder SignType where
   top := 1
-  le_top := Le.of_pos
+  le_top := LE.of_pos
   bot := -1
-  bot_le := Le.of_neg
+  bot_le := LE.of_neg
 
 instance : HasDistribNeg SignType :=
   { neg_neg := fun x => by cases x <;> rfl
@@ -135,8 +135,7 @@ instance : HasDistribNeg SignType :=
     mul_neg := fun x y => by cases x <;> cases y <;> rfl }
 
 /-- `SignType` is equivalent to `Fin 3`. -/
-def fin3Equiv : SignType ≃* Fin 3
-    where
+def fin3Equiv : SignType ≃* Fin 3 where
   toFun a :=
     match a with
     | 0 => ⟨0, by simp⟩
@@ -271,8 +270,7 @@ end cast
 
 /-- `SignType.cast` as a `MulWithZeroHom`. -/
 @[simps]
-def castHom {α} [MulZeroOneClass α] [HasDistribNeg α] : SignType →*₀ α
-    where
+def castHom {α} [MulZeroOneClass α] [HasDistribNeg α] : SignType →*₀ α where
   toFun := cast
   map_zero' := rfl
   map_one' := rfl
@@ -280,8 +278,8 @@ def castHom {α} [MulZeroOneClass α] [HasDistribNeg α] : SignType →*₀ α
 #align sign_type.cast_hom SignType.castHom
 
 --Porting note: new theorem
-theorem univ_eq : (Finset.univ : Finset SignType) = {0, -1, 1} :=
-  by decide
+theorem univ_eq : (Finset.univ : Finset SignType) = {0, -1, 1} := by
+  decide
 
 theorem range_eq {α} (f : SignType → α) : Set.range f = {f zero, f neg, f pos} := by
   classical rw [← Fintype.coe_image_univ, univ_eq]

• depends on: #5966

Co-authored-by: Eric Wieser <wieser.eric@gmail.com> Co-authored-by: Scott Morrison <scott.morrison@gmail.com>

@@ -2,15 +2,12 @@
 Copyright (c) 2022 Eric Rodriguez. All rights reserved.
 Released under Apache 2.0 license as described in the file LICENSE.
 Authors: Eric Rodriguez
-
-! This file was ported from Lean 3 source module data.sign
-! leanprover-community/mathlib commit 2445c98ae4b87eabebdde552593519b9b6dc350c
-! Please do not edit these lines, except to modify the commit id
-! if you have ported upstream changes.
 -/
 import Mathlib.Algebra.BigOperators.Order
 import Mathlib.Data.Fintype.BigOperators
 import Mathlib.Data.Int.Lemmas
+
+#align_import data.sign from "leanprover-community/mathlib"@"2445c98ae4b87eabebdde552593519b9b6dc350c"
 /-!
 # Sign function
 

Grepping for [^ .:{-] [^ :] and reviewing the results. Once I started I couldn't stop. :-)

Co-authored-by: Scott Morrison <scott.morrison@gmail.com>

@@ -279,7 +279,7 @@ def castHom {α} [MulZeroOneClass α] [HasDistribNeg α] : SignType →*₀ α
   toFun := cast
   map_zero' := rfl
   map_one' := rfl
-  map_mul' x y := by  cases x <;> cases y <;> simp [zero_eq_zero, pos_eq_one, neg_eq_neg_one]
+  map_mul' x y := by cases x <;> cases y <;> simp [zero_eq_zero, pos_eq_one, neg_eq_neg_one]
 #align sign_type.cast_hom SignType.castHom
 
 --Porting note: new theorem

@@ -504,7 +504,7 @@ private theorem exists_signed_sum_aux {α : Type u_1} [DecidableEq α] (s : Fins
       fun a => sign (f a.1), fun a => a.1, fun a => a.1.2, _, _⟩
   · simp [sum_attach (f := fun a => (f a).natAbs)]
   · intro x hx
-    simp [sum_sigma, hx, ← Int.sign_eq_sign, Int.sign_mul_abs, mul_comm (|f _|),
+    simp [sum_sigma, hx, ← Int.sign_eq_sign, Int.sign_mul_abs, mul_comm |f _|,
       sum_attach (s := s) (f := fun y => if y = x then f y else 0)]
 
 /-- We can decompose a sum of absolute value `n` into a sum of `n` signs. -/

Changes are of the form

• some_tactic at h⊢ -> some_tactic at h ⊢
• some_tactic at h -> some_tactic at h

@@ -470,11 +470,11 @@ attribute [local instance] LinearOrderedAddCommGroup.decidableLT
 theorem sign_sum {ι : Type _} {s : Finset ι} {f : ι → α} (hs : s.Nonempty) (t : SignType)
     (h : ∀ i ∈ s, sign (f i) = t) : sign (∑ i in s, f i) = t := by
   cases t
-  · simp_rw [zero_eq_zero, sign_eq_zero_iff] at h⊢
+  · simp_rw [zero_eq_zero, sign_eq_zero_iff] at h ⊢
     exact Finset.sum_eq_zero h
-  · simp_rw [neg_eq_neg_one, sign_eq_neg_one_iff] at h⊢
+  · simp_rw [neg_eq_neg_one, sign_eq_neg_one_iff] at h ⊢
     exact Finset.sum_neg h hs
-  · simp_rw [pos_eq_one, sign_eq_one_iff] at h⊢
+  · simp_rw [pos_eq_one, sign_eq_one_iff] at h ⊢
     exact Finset.sum_pos h hs
 #align sign_sum sign_sum
 

• Run a non-interactive version of fix-comments.py on all files.
• Go through the diff and manually add/discard/edit chunks.

@@ -241,7 +241,7 @@ section cast
 variable {α : Type _} [Zero α] [One α] [Neg α]
 
 /-- Turn a `SignType` into zero, one, or minus one. This is a coercion instance, but note it is
-only a `has_coe_t` instance: see note [use has_coe_t]. -/
+only a `CoeTC` instance: see note [use has_coe_t]. -/
 @[coe]
 def cast : SignType → α
   | zero => 0
@@ -415,10 +415,11 @@ theorem sign_mul (x y : α) : sign (x * y) = sign x * sign y := by
   · rw [abs_zero, zero_mul]
   · rw [sign_pos hx, abs_of_pos hx, coe_one, mul_one]
 
-/-- `sign` as a `MonoidWithZeroHom` for a nontrivial ordered semiring. Note that linearity
+/-- `SignType.sign` as a `MonoidWithZeroHom` for a nontrivial ordered semiring. Note that linearity
 is required; consider ℂ with the order `z ≤ w` iff they have the same imaginary part and
-`z - w ≤ 0` in the reals; then `1 + i` and `1 - i` are incomparable to zero, and thus we have:
-`0 * 0 = sign (1 + i) * sign (1 - i) ≠ sign 2 = 1`. (`Complex.orderedCommRing`) -/
+`z - w ≤ 0` in the reals; then `1 + I` and `1 - I` are incomparable to zero, and thus we have:
+`0 * 0 = SignType.sign (1 + I) * SignType.sign (1 - I) ≠ SignType.sign 2 = 1`.
+(`Complex.orderedCommRing`) -/
 def signHom : α →*₀ SignType where
   toFun := sign
   map_zero' := sign_zero

This renames

• decidable_eq to decidableEq
• decidable_lt to decidableLT
• decidable_le to decidableLE
• decidableLT_of_decidableLE to decidableLTOfDecidableLE
• decidableEq_of_decidableLE to decidableEqOfDecidableLE

These fields are data not proofs, so they should be lowerCamelCased.

@@ -123,8 +123,8 @@ instance : LinearOrder SignType where
   le_total a b := by cases a <;> cases b <;> first | left; constructor | right; constructor
   le_antisymm := le_antisymm
   le_trans := le_trans
-  decidable_le := Le.decidableRel
-  decidable_eq := SignType.decidableEq
+  decidableLE := Le.decidableRel
+  decidableEq := SignType.decidableEq
 
 instance : BoundedOrder SignType where
   top := 1
@@ -396,7 +396,7 @@ variable [LinearOrderedRing α] {a b : α}
 
 /- I'm not sure why this is necessary, see https://leanprover.zulipchat.com/#narrow/stream/
 113488-general/topic/type.20class.20inference.20issues/near/276937942 -/
-attribute [local instance] LinearOrderedRing.decidable_lt
+attribute [local instance] LinearOrderedRing.decidableLT
 
 theorem sign_mul (x y : α) : sign (x * y) = sign x * sign y := by
   rcases lt_trichotomy x 0 with (hx | hx | hx) <;> rcases lt_trichotomy y 0 with (hy | hy | hy) <;>
@@ -464,7 +464,7 @@ variable [LinearOrderedAddCommGroup α]
 /- I'm not sure why this is necessary, see
 https://leanprover.zulipchat.com/#narrow/stream/113488-general/topic/Decidable.20vs.20decidable_rel
 -/
-attribute [local instance] LinearOrderedAddCommGroup.decidable_lt
+attribute [local instance] LinearOrderedAddCommGroup.decidableLT
 
 theorem sign_sum {ι : Type _} {s : Finset ι} {f : ι → α} (hs : s.Nonempty) (t : SignType)
     (h : ∀ i ∈ s, sign (f i) = t) : sign (∑ i in s, f i) = t := by

This PR puts, with one exception, every single remaining by that lies all by itself on its own line to the previous line, thus matching the current behaviour of start-port.sh. The exception is when the by begins the second or later argument to a tuple or anonymous constructor; see https://github.com/leanprover-community/mathlib4/pull/3825#discussion_r1186702599.

Essentially this is s/\n *by$/ by/g, but with manual editing to satisfy the linter's max-100-char-line requirement. The Python style linter is also modified to catch these "isolated bys".

@@ -304,8 +304,7 @@ variable [Zero α] [Preorder α] [DecidableRel ((· < ·) : α → α → Prop)]
 -- Porting note: needed to rename this from sign to SignType.sign to avoid ambiguity with Int.sign
 /-- The sign of an element is 1 if it's positive, -1 if negative, 0 otherwise. -/
 def SignType.sign : α →o SignType :=
-  ⟨fun a => if 0 < a then 1 else if a < 0 then -1 else 0, fun a b h =>
-    by
+  ⟨fun a => if 0 < a then 1 else if a < 0 then -1 else 0, fun a b h => by
     dsimp
     split_ifs with h₁ h₂ h₃ h₄ _ _ h₂ h₃ <;> try constructor
     · cases lt_irrefl 0 (h₁.trans <| h.trans_lt h₃)

This single file uses more than twice as much RAM as the next largest file in mathlib, see https://leanprover.zulipchat.com/#narrow/stream/287929-mathlib4/topic/mathlib4.20speedcenter/near/342595677. A simple out-lining fixes the issue.

@@ -90,9 +90,10 @@ instance Le.decidableRel : DecidableRel Le := fun a b => by
 instance decidableEq : DecidableEq SignType := fun a b => by
   cases a <;> cases b <;> first | exact isTrue (by constructor)| exact isFalse (by rintro ⟨_⟩)
 
+private lemma mul_comm : ∀ (a b : SignType), a * b = b * a := by rintro ⟨⟩ ⟨⟩ <;> rfl
+private lemma mul_assoc : ∀ (a b c : SignType), (a * b) * c = a * (b * c) := by
+  rintro ⟨⟩ ⟨⟩ ⟨⟩ <;> rfl
 
-set_option maxHeartbeats 0
--- Porting note: This takes too long, likely fixed by lean4#2003
 /- We can define a `Field` instance on `SignType`, but it's not mathematically sensible,
 so we only define the `CommGroupWithZero`. -/
 instance : CommGroupWithZero SignType where
@@ -105,17 +106,23 @@ instance : CommGroupWithZero SignType where
   mul_one a := by cases a <;> rfl
   one_mul a := by cases a <;> rfl
   mul_inv_cancel a ha := by cases a <;> trivial
-  mul_comm a b := by cases a <;> cases b <;> rfl
-  mul_assoc a b c := by cases a <;> cases b <;> cases c <;> rfl
+  mul_comm := mul_comm
+  mul_assoc := mul_assoc
   exists_pair_ne := ⟨0, 1, by rintro ⟨_⟩⟩
   inv_zero := rfl
 
+private lemma le_antisymm (a b : SignType) (_ : a ≤ b) (_: b ≤ a) : a = b := by
+  cases a <;> cases b <;> trivial
+
+private lemma le_trans (a b c : SignType) (_ : a ≤ b) (_: b ≤ c) : a ≤ c := by
+  cases a <;> cases b <;> cases c <;> first | tauto | constructor
+
 instance : LinearOrder SignType where
   le := (· ≤ ·)
   le_refl a := by cases a <;> constructor
   le_total a b := by cases a <;> cases b <;> first | left; constructor | right; constructor
-  le_antisymm a b ha hb := by cases a <;> cases b <;> trivial
-  le_trans a b c hab hbc := by cases a <;> cases b <;> cases c <;> first | tauto | constructor
+  le_antisymm := le_antisymm
+  le_trans := le_trans
   decidable_le := Le.decidableRel
   decidable_eq := SignType.decidableEq
 

@@ -397,6 +397,18 @@ theorem sign_mul (x y : α) : sign (x * y) = sign x * sign y := by
     simp [hx, hy, mul_pos_of_neg_of_neg, mul_neg_of_neg_of_pos, mul_neg_of_pos_of_neg]
 #align sign_mul sign_mul
 
+@[simp] theorem sign_mul_abs (x : α) : (sign x * |x| : α) = x := by
+  rcases lt_trichotomy x 0 with (hx | rfl | hx)
+  · rw [sign_neg hx, abs_of_neg hx, coe_neg_one, neg_one_mul, neg_neg]
+  · rw [abs_zero, mul_zero]
+  · rw [sign_pos hx, abs_of_pos hx, coe_one, one_mul]
+
+@[simp] theorem abs_mul_sign (x : α) : (|x| * sign x : α) = x := by
+  rcases lt_trichotomy x 0 with (hx | rfl | hx)
+  · rw [sign_neg hx, abs_of_neg hx, coe_neg_one, mul_neg_one, neg_neg]
+  · rw [abs_zero, zero_mul]
+  · rw [sign_pos hx, abs_of_pos hx, coe_one, mul_one]
+
 /-- `sign` as a `MonoidWithZeroHom` for a nontrivial ordered semiring. Note that linearity
 is required; consider ℂ with the order `z ≤ w` iff they have the same imaginary part and
 `z - w ≤ 0` in the reals; then `1 + i` and `1 - i` are incomparable to zero, and thus we have:
@@ -408,9 +420,7 @@ def signHom : α →*₀ SignType where
   map_mul' := sign_mul
 #align sign_hom signHom
 
-theorem sign_pow (x : α) (n : ℕ) : sign (x ^ n) = sign x ^ n := by
-  change signHom (x ^ n) = signHom x ^ n
-  exact map_pow _ _ _
+theorem sign_pow (x : α) (n : ℕ) : sign (x ^ n) = sign x ^ n := map_pow signHom x n
 #align sign_pow sign_pow
 
 end LinearOrderedRing

This is now done, but had some difficulties.

• A lot of theorems used to be proved by decide!, which is not yet implemented.
• deriving FinType does not work yet, manually inserted that instance
• Many proofs relied on casesm and casesm*, which appear to work differently than they did in lean3 (see also this zulip thread).
• Lean 4 was unable to infer DecidableEq for SignType, manually inserted that instance as well.

Co-authored-by: ChrisHughes24 <chrishughes24@gmail.com>