simp only [heq] at h
n : Nat
arr : Array (Option (DefaultClause n))
hsize✝ : (ofArray arr).assignments.size = n
modified_assignments_invariant : Array Assignment → Prop :=
  fun assignments =>
    ∃ hsize, ∀ (i : PosFin n) (b : Bool), hasAssignment b assignments[i.val] = true → unit (i, b) ∈ (ofArray arr).toList
hb : modified_assignments_invariant (mkArray n unassigned)
acc : Array Assignment
ih : modified_assignments_invariant acc
i : PosFin n
b : Bool
cOpt : Option (DefaultClause n)
c : DefaultClause n
cOpt_in_arr : some c ∈ arr.data
hsize : (ofArray_fold_fn acc (some c)).size = n
h :
  hasAssignment b
      (match c.isUnit with
        | none => acc
        | some (l, true) => acc.modify l.val addPosAssignment
        | some (l, false) => acc.modify l.val addNegAssignment)[i.val] =
    true
l : PosFin n
heq : c.isUnit = some (l, false)
⊢ unit (i, b) ∈ (ofArray arr).toList
n : Nat
arr : Array (Option (DefaultClause n))
hsize✝ : (ofArray arr).assignments.size = n
modified_assignments_invariant : Array Assignment → Prop :=
  fun assignments =>
    ∃ hsize, ∀ (i : PosFin n) (b : Bool), hasAssignment b assignments[i.val] = true → unit (i, b) ∈ (ofArray arr).toList
hb : modified_assignments_invariant (mkArray n unassigned)
acc : Array Assignment
ih : modified_assignments_invariant acc
i : PosFin n
b : Bool
cOpt : Option (DefaultClause n)
c : DefaultClause n
cOpt_in_arr : some c ∈ arr.data
hsize : (ofArray_fold_fn acc (some c)).size = n
l : PosFin n
heq : c.isUnit = some (l, false)
h : hasAssignment b (acc.modify l.val addNegAssignment)[i.val] = true
⊢ unit (i, b) ∈ (ofArray arr).toList