∀ {α : Type} {decls : Array (Std.Sat.AIG.Decl α)} {decl : Std.Sat.AIG.Decl α} (idx : ℕ) (hbound : idx < decls.size)
  (hvalid : decls[idx] = decl) (idx_1 : ℕ) (hbound_1 : idx_1 < decls.size) (hvalid_1 : decls[idx_1] = decl),
  ({ idx := idx, hbound := hbound, hvalid := hvalid } = { idx := idx_1, hbound := hbound_1, hvalid := hvalid_1 }) =
    (idx = idx_1)