diff --git a/bench/dtgbasat/gen.py b/bench/dtgbasat/gen.py
index e96bf2825..dabf77971 100755
--- a/bench/dtgbasat/gen.py
+++ b/bench/dtgbasat/gen.py
@@ -1,5 +1,5 @@
 #!/usr/bin/env python3
-# Copyright (C) 2016-2018 Laboratoire de Recherche et Développement de
+# Copyright (C) 2016-2018, 2023 Laboratoire de Recherche et Développement de
 # l'Epita (LRDE).
 #
 # This file is part of Spot, a model checking library.
@@ -55,12 +55,12 @@ class BenchConfig(object):
                 if line[0] == '#' or line.isspace():
                     continue
                 elif line[0:2] == "sh":
-                    sh = re.search('sh (.+?)$', line).group(1)
+                    sh = re.search('sh (.+)$', line).group(1)
                     continue
                 else:
                     name = re.search('(.+?):', line).group(1)
                     code = re.search(':(.+?)>', line).group(1)
-                    xoptions = re.search('>(.+?)$', line).group(1)
+                    xoptions = re.search('>(.+)$', line).group(1)
                     b = Bench(name=name, code=code, xoptions=xoptions)
                     self.l.append(b)
                     self.sh.append(sh)
diff --git a/bin/autcross.cc b/bin/autcross.cc
index 24cd9bcd4..b3e504bb3 100644
--- a/bin/autcross.cc
+++ b/bin/autcross.cc
@@ -1,5 +1,5 @@
 // -*- coding: utf-8 -*-
-// Copyright (C) 2017-2020, 2022 Laboratoire de Recherche et
+// Copyright (C) 2017-2020, 2022-2023 Laboratoire de Recherche et
 // Développement de l'Epita (LRDE).
 //
 // This file is part of Spot, a model checking library.
@@ -549,7 +549,7 @@ namespace
       {
         if (!quiet)
           std::cerr << "info: building " << autname(i, is_really_comp(i))
-                    << '*' << autname(j, true ^ is_really_comp(j))
+                    << '*' << autname(j, !is_really_comp(j))
                     << " requires more acceptance sets than supported\n";
         return false;
       }
@@ -557,14 +557,14 @@ namespace
     if (verbose)
       std::cerr << "info: check_empty "
                 << autname(i, is_really_comp(i))
-                << '*' << autname(j, true ^ is_really_comp(j)) << '\n';
+                << '*' << autname(j, !is_really_comp(j)) << '\n';
 
     auto w = aut_i->intersecting_word(aut_j);
     if (w)
       {
         std::ostream& err = global_error();
         err << "error: " << autname(i, is_really_comp(i))
-            << '*' << autname(j, true ^ is_really_comp(j))
+            << '*' << autname(j, !is_really_comp(j))
             << (" is nonempty; both automata accept the infinite word:\n"
                 "       ");
         example() << *w << '\n';
@@ -613,7 +613,7 @@ namespace
           return src.str();
         }();
 
-      input_statistics.push_back(in_statistics());
+      input_statistics.emplace_back(in_statistics());
 
       input_statistics[round_num].input_source = std::move(source);
       if (auto name = input->get_named_prop<std::string>("automaton-name"))
@@ -658,7 +658,7 @@ namespace
           problems += prob;
         }
       spot::cleanup_tmpfiles();
-      output_statistics.push_back(std::move(stats));
+      output_statistics.emplace_back(std::move(stats));
 
       if (verbose)
         {
diff --git a/bin/autfilt.cc b/bin/autfilt.cc
index 7cff60e8b..b55d1bc9f 100644
--- a/bin/autfilt.cc
+++ b/bin/autfilt.cc
@@ -1,5 +1,5 @@
 // -*- coding: utf-8 -*-
-// Copyright (C) 2013-2022 Laboratoire de Recherche et Développement
+// Copyright (C) 2013-2023 Laboratoire de Recherche et Développement
 // de l'Epita (LRDE).
 //
 // This file is part of Spot, a model checking library.
@@ -448,7 +448,7 @@ struct canon_aut
   std::vector<tr_t> edges;
   std::string acc;
 
-  canon_aut(const spot::const_twa_graph_ptr& aut)
+  explicit canon_aut(const spot::const_twa_graph_ptr& aut)
     : num_states(aut->num_states())
     , edges(aut->edge_vector().begin() + 1,
             aut->edge_vector().end())
@@ -755,6 +755,22 @@ product_or(spot::twa_graph_ptr left, spot::twa_graph_ptr right)
   return spot::product_or(left, right);
 }
 
+static spot::twa_graph_ptr
+word_to_aut(const char* word, const char *argname)
+{
+  try
+    {
+      return spot::parse_word(word, opt->dict)->as_automaton();
+    }
+  catch (const spot::parse_error& e)
+    {
+      error(2, 0, "failed to parse the argument of --%s:\n%s",
+            argname, e.what());
+    }
+  SPOT_UNREACHABLE();
+  return nullptr;
+}
+
 static int
 parse_opt(int key, char* arg, struct argp_state*)
 {
@@ -776,17 +792,14 @@ parse_opt(int key, char* arg, struct argp_state*)
       opt_nth = parse_range(arg, 0, std::numeric_limits<int>::max());
       break;
     case 'u':
-      opt->uniq = std::unique_ptr<unique_aut_t>(new std::set<canon_aut>());
+      opt->uniq = std::make_unique<unique_aut_t>();
       break;
     case 'v':
       opt_invert = true;
       break;
     case 'x':
-      {
-        const char* opt = extra_options.parse_options(arg);
-        if (opt)
-          error(2, 0, "failed to parse --options near '%s'", opt);
-      }
+      if (const char* opt = extra_options.parse_options(arg))
+        error(2, 0, "failed to parse --options near '%s'", opt);
       break;
     case OPT_ALIASES:
       opt_aliases = XARGMATCH("--aliases", arg, aliases_args, aliases_types);
@@ -802,16 +815,7 @@ parse_opt(int key, char* arg, struct argp_state*)
       opt_art_sccs_set = true;
       break;
     case OPT_ACCEPT_WORD:
-      try
-        {
-          opt->acc_words.push_back(spot::parse_word(arg, opt->dict)
-                                   ->as_automaton());
-        }
-      catch (const spot::parse_error& e)
-        {
-          error(2, 0, "failed to parse the argument of --accept-word:\n%s",
-                e.what());
-        }
+      opt->acc_words.emplace_back(word_to_aut(arg, "accept-word"));
       break;
     case OPT_ACCEPTANCE_IS:
       {
@@ -964,16 +968,7 @@ parse_opt(int key, char* arg, struct argp_state*)
                     "%d should be followed by a comma and WORD", res);
             arg = endptr + 1;
           }
-        try
-          {
-            opt->hl_words.emplace_back(spot::parse_word(arg, opt->dict)
-                                       ->as_automaton(), res);
-          }
-        catch (const spot::parse_error& e)
-          {
-            error(2, 0, "failed to parse the argument of --highlight-word:\n%s",
-                  e.what());
-          }
+        opt->hl_words.emplace_back(word_to_aut(arg, "highlight-word"), res);
       }
       break;
     case OPT_HIGHLIGHT_LANGUAGES:
@@ -1157,16 +1152,7 @@ parse_opt(int key, char* arg, struct argp_state*)
       opt_art_sccs_set = true;
       break;
     case OPT_REJECT_WORD:
-      try
-        {
-          opt->rej_words.push_back(spot::parse_word(arg, opt->dict)
-                                   ->as_automaton());
-        }
-      catch (const spot::parse_error& e)
-        {
-          error(2, 0, "failed to parse the argument of --reject-word:\n%s",
-                e.what());
-        }
+      opt->rej_words.emplace_back(word_to_aut(arg, "reject-word"));
       break;
     case OPT_REM_AP:
       opt->rem_ap.add_ap(arg);
@@ -1291,7 +1277,7 @@ namespace
   static
   bool match_acceptance(spot::twa_graph_ptr aut)
   {
-    auto& acc = aut->acc();
+    const spot::acc_cond& acc = aut->acc();
     switch (opt_acceptance_is)
       {
       case ACC_Any:
@@ -1346,8 +1332,7 @@ namespace
         {
           bool max;
           bool odd;
-          bool is_p = acc.is_parity(max, odd, true);
-          if (!is_p)
+          if (!acc.is_parity(max, odd, true))
             return false;
           switch (opt_acceptance_is)
             {
@@ -1460,7 +1445,7 @@ namespace
       if (matched && opt_acceptance_is)
         matched = match_acceptance(aut);
 
-      if (matched && (opt_sccs_set | opt_art_sccs_set))
+      if (matched && (opt_sccs_set || opt_art_sccs_set))
         {
           spot::scc_info si(aut);
           unsigned n = si.scc_count();
@@ -1540,14 +1525,14 @@ namespace
           && spot::contains(aut, opt->equivalent_pos);
 
       if (matched && !opt->acc_words.empty())
-        for (auto& word_aut: opt->acc_words)
+        for (const spot::twa_graph_ptr& word_aut: opt->acc_words)
           if (spot::product(aut, word_aut)->is_empty())
             {
               matched = false;
               break;
             }
       if (matched && !opt->rej_words.empty())
-        for (auto& word_aut: opt->rej_words)
+        for (const spot::twa_graph_ptr& word_aut: opt->rej_words)
           if (!spot::product(aut, word_aut)->is_empty())
             {
               matched = false;
@@ -1681,13 +1666,13 @@ namespace
         aut->accepting_run()->highlight(opt_highlight_accepting_run);
 
       if (!opt->hl_words.empty())
-        for (auto& word_aut: opt->hl_words)
+        for (auto& [word_aut, color]: opt->hl_words)
           {
             if (aut->acc().uses_fin_acceptance())
               error(2, 0,
                     "--highlight-word does not yet work with Fin acceptance");
-            if (auto run = spot::product(aut, word_aut.first)->accepting_run())
-              run->project(aut)->highlight(word_aut.second);
+            if (auto run = spot::product(aut, word_aut)->accepting_run())
+              run->project(aut)->highlight(color);
           }
 
       timer.stop();
diff --git a/bin/common_aoutput.cc b/bin/common_aoutput.cc
index fcc79fc3c..60f83289e 100644
--- a/bin/common_aoutput.cc
+++ b/bin/common_aoutput.cc
@@ -1,5 +1,5 @@
 // -*- coding: utf-8 -*-
-// Copyright (C) 2012-2022 Laboratoire de Recherche et Développement
+// Copyright (C) 2012-2023 Laboratoire de Recherche et Développement
 // de l'Epita (LRDE).
 //
 // This file is part of Spot, a model checking library.
@@ -453,7 +453,7 @@ hoa_stat_printer::print(const spot::const_parsed_aut_ptr& haut,
                         const spot::const_twa_graph_ptr& aut,
                         spot::formula f,
                         const char* filename, int loc,
-                        spot::process_timer& ptimer,
+                        const spot::process_timer& ptimer,
                         const char* csv_prefix, const char* csv_suffix)
 {
   timer_ = ptimer;
@@ -633,10 +633,10 @@ automaton_printer::print(const spot::twa_graph_ptr& aut,
       outputnamer.print(haut, aut, f, filename, loc, ptimer,
                         csv_prefix, csv_suffix);
       std::string fname = outputname.str();
-      auto p = outputfiles.emplace(fname, nullptr);
-      if (p.second)
-        p.first->second.reset(new output_file(fname.c_str()));
-      out = &p.first->second->ostream();
+      auto [it, b] = outputfiles.try_emplace(fname, nullptr);
+      if (b)
+        it->second.reset(new output_file(fname.c_str()));
+      out = &it->second->ostream();
     }
 
   // Output it.
diff --git a/bin/common_aoutput.hh b/bin/common_aoutput.hh
index d33b687d2..f57beae84 100644
--- a/bin/common_aoutput.hh
+++ b/bin/common_aoutput.hh
@@ -1,6 +1,6 @@
 // -*- coding: utf-8 -*-
-// Copyright (C) 2014-2018, 2020, 2022 Laboratoire de Recherche et
-// Développement de l'Epita (LRDE).
+// Copyright (C) 2014-2018, 2020, 2022, 2023 Laboratoire de Recherche
+// et Développement de l'Epita (LRDE).
 //
 // This file is part of Spot, a model checking library.
 //
@@ -155,7 +155,7 @@ public:
     print(const spot::const_parsed_aut_ptr& haut,
         const spot::const_twa_graph_ptr& aut,
         spot::formula f,
-        const char* filename, int loc, spot::process_timer& ptimer,
+        const char* filename, int loc, const spot::process_timer& ptimer,
         const char* csv_prefix, const char* csv_suffix);
 
 private:
@@ -196,7 +196,7 @@ class automaton_printer
   std::map<std::string, std::unique_ptr<output_file>> outputfiles;
 
 public:
-  automaton_printer(stat_style input = no_input);
+  explicit automaton_printer(stat_style input = no_input);
   ~automaton_printer();
 
   void