module
abbrev f (a : α) := a
set_option grind.debug true
set_option grind.debug.proofs true

/--
error: `grind` failed
case grind
a b c : Bool
p q : Prop
h : (f a && (b || f (f c))) = true
h' : p ∧ q
h_1 : (b && a) = false
⊢ False
[grind] Goal diagnostics
  [facts] Asserted facts
    [prop] a = true ∧ (b = true ∨ c = true)
    [prop] p ∧ q
    [prop] (b && a) = false
  [eqc] True propositions
    [prop] p
    [prop] q
    [prop] p ∧ q
    [prop] a = true ∧ (b = true ∨ c = true)
    [prop] b = true ∨ c = true
    [prop] a = true
    [prop] c = true
  [eqc] False propositions
    [prop] b = true
  [eqc] Equivalence classes
    [eqc] {a, c, true}
    [eqc] {b, false, b && a}
  [assoc] Operator `and`
    [basis] Basis
      [_] a = true
    [diseqs] Disequalities
      [_] b ≠ true
    [properties] Properties
      [_] commutative
      [_] idempotent
      [_] identity: `true`
-/
#guard_msgs (error) in
theorem ex (h : (f a && (b || f (f c))) = true) (h' : p ∧ q) : b && a := by
  grind

section
attribute [local grind cases eager] Or

/--
error: `grind` failed
case grind
a b c : Bool
p q : Prop
h : (f a && (b || f (f c))) = true
h' : p ∧ q
h_1 : (b && a) = false
⊢ False
[grind] Goal diagnostics
  [facts] Asserted facts
    [prop] a = true ∧ (b = true ∨ c = true)
    [prop] p ∧ q
    [prop] (b && a) = false
  [eqc] True propositions
    [prop] p
    [prop] q
    [prop] p ∧ q
    [prop] a = true ∧ (b = true ∨ c = true)
    [prop] b = true ∨ c = true
    [prop] a = true
    [prop] c = true
  [eqc] False propositions
    [prop] b = true
  [eqc] Equivalence classes
    [eqc] {a, c, true}
    [eqc] {b, false, b && a}
  [assoc] Operator `and`
    [basis] Basis
      [_] a = true
    [diseqs] Disequalities
      [_] b ≠ true
    [properties] Properties
      [_] commutative
      [_] idempotent
      [_] identity: `true`
-/
#guard_msgs (error) in
theorem ex2 (h : (f a && (b || f (f c))) = true) (h' : p ∧ q) : b && a := by
  grind

end

def g (i : Nat) (j : Nat) (_ : i > j := by omega) := i + j

structure Point where
  x : Nat
  y : Int

/--
error: `grind` failed
case grind
a₁ : Point
a₂ : Nat
a₃ : Int
as : List Point
b₁ : Point
bs : List Point
b₂ : Nat
b₃ : Int
h : a₁ :: { x := a₂, y := a₃ } :: as = b₁ :: { x := b₂, y := b₃ } :: bs
⊢ False
[grind] Goal diagnostics
  [facts] Asserted facts
    [prop] a₁ :: { x := a₂, y := a₃ } :: as = b₁ :: { x := b₂, y := b₃ } :: bs
  [eqc] Equivalence classes
    [eqc] {a₁, b₁}
    [eqc] {a₂, b₂}
    [eqc] {a₃, b₃}
    [eqc] {as, bs}
    [eqc] {{ x := a₂, y := a₃ }, { x := b₂, y := b₃ }}
    [eqc] {a₁ :: { x := a₂, y := a₃ } :: as, b₁ :: { x := b₂, y := b₃ } :: bs}
    [eqc] {{ x := a₂, y := a₃ } :: as, { x := b₂, y := b₃ } :: bs}
-/
#guard_msgs (error) in
theorem ex3 (h : a₁ :: { x := a₂, y := a₃ : Point } :: as = b₁ :: { x := b₂, y := b₃} :: bs) : False := by
  grind

def h (a : α) := a

example (p : Prop) (a b c : Nat) : p → a = 0 → a = b → h a = h c → a = c ∧ c = a → a = b ∧ b = a → a = c := by
  grind

set_option trace.grind.debug.proof true
/--
error: `grind` failed
case grind.1
α : Type
a : α
p q r : Prop
h₁ : p ≍ a
h₂ : q ≍ a
h₃ : p = r
left : p
right : r
⊢ False
[grind] Goal diagnostics
  [facts] Asserted facts
    [prop] p ≍ a
    [prop] q ≍ a
    [prop] p = r
    [prop] p
    [prop] r
  [eqc] True propositions
    [prop] a
    [prop] p
    [prop] q
    [prop] r
    [prop] p = r
  [cases] Case analyses
    [cases] [1/2]: p = r
      [cases] source: Initial goal
-/
#guard_msgs (error) in
example (a : α) (p q r : Prop) : (h₁ : p ≍ a) → (h₂ : q ≍ a) → (h₃ : p = r) → False := by
  grind

example (a b : Nat) (f : Nat → Nat) : (h₁ : a = b) → (h₂ : f a ≠ f b) → False := by
  grind

example (a : α) (p q r : Prop) : (h₁ : p ≍ a) → (h₂ : q ≍ a) → (h₃ : p = r) → q = r := by
  grind

/--
trace: [sym.issues] found congruence between
      g b
    and
      f a
    but functions have different types
-/
#guard_msgs (trace) in
set_option trace.sym.issues true in
set_option trace.grind.debug.proof false in
example (f : Nat → Bool) (g : Int → Bool) (a : Nat) (b : Int) : f ≍ g → a ≍ b → f a = g b := by
  fail_if_success grind
  sorry

/--
error: `grind` failed
case grind
f : Nat → Bool
g : Int → Bool
a : Nat
b : Int
h : f ≍ g
h_1 : a ≍ b
h_2 : ¬f a = g b
⊢ False
[grind] Goal diagnostics
  [facts] Asserted facts
    [prop] f ≍ g
    [prop] a ≍ b
    [prop] ¬f a = g b
  [eqc] False propositions
    [prop] f a = g b
  [eqc] Equivalence classes
    [eqc] {f, g}
    [eqc] {a, b}
[grind] Issues
  [issue] found congruence between
        g b
      and
        f a
      but functions have different types
-/
#guard_msgs (error) in
example (f : Nat → Bool) (g : Int → Bool) (a : Nat) (b : Int) : f ≍ g → a ≍ b → f a = g b := by
  grind