diff --git a/include/fcarouge/internal/kalman.hpp b/include/fcarouge/internal/kalman.hpp
index e7f98b0ca..21f462111 100644
--- a/include/fcarouge/internal/kalman.hpp
+++ b/include/fcarouge/internal/kalman.hpp
@@ -107,44 +107,29 @@ struct kalman<State, Output, void, Divide, pack<UpdateTypes...>,
   //! specialized cases? Same question applies to other parameters.
   //! @todo Pass the arguments by universal reference?
   observation_state_function observation_state_h{
-      [&h = h](const state &state_x,
-               const UpdateTypes &...update_pack) -> output_model {
-        static_cast<void>(state_x);
-        (static_cast<void>(update_pack), ...);
-        return h;
-      }};
+      [&h = h]([[maybe_unused]] const state &state_x,
+               [[maybe_unused]] const UpdateTypes &...update_pack)
+          -> output_model { return h; }};
   noise_observation_function noise_observation_r{
-      [&r = r](const state &state_x, const output &output_z,
-               const UpdateTypes &...update_pack) -> output_uncertainty {
-        static_cast<void>(state_x);
-        static_cast<void>(output_z);
-        (static_cast<void>(update_pack), ...);
-        return r;
-      }};
+      [&r = r]([[maybe_unused]] const state &state_x,
+               [[maybe_unused]] const output &output_z,
+               [[maybe_unused]] const UpdateTypes &...update_pack)
+          -> output_uncertainty { return r; }};
   transition_state_function transition_state_f{
-      [&f = f](const state &state_x,
-               const PredictionTypes &...prediction_pack) -> state_transition {
-        static_cast<void>(state_x);
-        (static_cast<void>(prediction_pack), ...);
-        return f;
-      }};
+      [&f = f]([[maybe_unused]] const state &state_x,
+               [[maybe_unused]] const PredictionTypes &...prediction_pack)
+          -> state_transition { return f; }};
   noise_process_function noise_process_q{
-      [&q = q](const state &state_x, const PredictionTypes &...prediction_pack)
-          -> process_uncertainty {
-        static_cast<void>(state_x);
-        (static_cast<void>(prediction_pack), ...);
-        return q;
-      }};
+      [&q = q]([[maybe_unused]] const state &state_x,
+               [[maybe_unused]] const PredictionTypes &...prediction_pack)
+          -> process_uncertainty { return q; }};
   transition_function transition{
       [&f = f](const state &state_x,
-               const PredictionTypes &...prediction_pack) -> state {
-        (static_cast<void>(prediction_pack), ...);
-        return f * state_x;
-      }};
+               [[maybe_unused]] const PredictionTypes &...prediction_pack)
+          -> state { return f * state_x; }};
   observation_function observation{
       [&h = h](const state &state_x,
-               const UpdateTypes &...update_pack) -> output {
-        (static_cast<void>(update_pack), ...);
+               [[maybe_unused]] const UpdateTypes &...update_pack) -> output {
         return h * state_x;
       }};
 
@@ -238,50 +223,35 @@ struct kalman<State, Output, Input, Divide, pack<UpdateTypes...>,
   //! specialized cases? Same question applies to other parameters.
   //! @todo Pass the arguments by universal reference?
   observation_state_function observation_state_h{
-      [&h = h](const state &state_x,
-               const UpdateTypes &...update_pack) -> output_model {
-        static_cast<void>(state_x);
-        (static_cast<void>(update_pack), ...);
-        return h;
-      }};
+      [&h = h]([[maybe_unused]] const state &state_x,
+               [[maybe_unused]] const UpdateTypes &...update_pack)
+          -> output_model { return h; }};
   noise_observation_function noise_observation_r{
-      [&r = r](const state &state_x, const output &output_z,
-               const UpdateTypes &...update_pack) -> output_uncertainty {
-        static_cast<void>(state_x);
-        static_cast<void>(output_z);
-        (static_cast<void>(update_pack), ...);
-        return r;
-      }};
+      [&r = r]([[maybe_unused]] const state &state_x,
+               [[maybe_unused]] const output &output_z,
+               [[maybe_unused]] const UpdateTypes &...update_pack)
+          -> output_uncertainty { return r; }};
   transition_state_function transition_state_f{
-      [&f = f](const state &state_x, const input &input_u,
-               const PredictionTypes &...prediction_pack) -> state_transition {
-        static_cast<void>(state_x);
-        static_cast<void>(input_u);
-        (static_cast<void>(prediction_pack), ...);
-        return f;
-      }};
+      [&f = f]([[maybe_unused]] const state &state_x,
+               [[maybe_unused]] const input &input_u,
+               [[maybe_unused]] const PredictionTypes &...prediction_pack)
+          -> state_transition { return f; }};
   noise_process_function noise_process_q{
-      [&q = q](const state &state_x, const PredictionTypes &...prediction_pack)
-          -> process_uncertainty {
-        static_cast<void>(state_x);
-        (static_cast<void>(prediction_pack), ...);
-        return q;
-      }};
+      [&q = q]([[maybe_unused]] const state &state_x,
+               [[maybe_unused]] const PredictionTypes &...prediction_pack)
+          -> process_uncertainty { return q; }};
   transition_control_function transition_control_g{
-      [&g = g](const PredictionTypes &...prediction_pack) -> input_control {
-        (static_cast<void>(prediction_pack), ...);
-        return g;
-      }};
+      [&g = g]([[maybe_unused]] const PredictionTypes &...prediction_pack)
+          -> input_control { return g; }};
   transition_function transition{
-      [&f = f, &g = g](const state &state_x, const input &input_u,
-                       const PredictionTypes &...prediction_pack) -> state {
-        (static_cast<void>(prediction_pack), ...);
+      [&f = f, &g = g](
+          const state &state_x, const input &input_u,
+          [[maybe_unused]] const PredictionTypes &...prediction_pack) -> state {
         return f * state_x + g * input_u;
       }};
   observation_function observation{
       [&h = h](const state &state_x,
-               const UpdateTypes &...update_pack) -> output {
-        (static_cast<void>(update_pack), ...);
+               [[maybe_unused]] const UpdateTypes &...update_pack) -> output {
         return h * state_x;
       }};
 
diff --git a/include/fcarouge/internal/utility.hpp b/include/fcarouge/internal/utility.hpp
index 79f0e3948..ab8d009a0 100644
--- a/include/fcarouge/internal/utility.hpp
+++ b/include/fcarouge/internal/utility.hpp
@@ -48,9 +48,8 @@ template <typename Type>
 concept arithmetic = std::integral<Type> || std::floating_point<Type>;
 
 struct empty {
-  inline constexpr explicit empty(auto &&...any) noexcept {
+  inline constexpr explicit empty([[maybe_unused]] auto &&...any) noexcept {
     // Constructs from anything for all initializations compatibility.
-    (static_cast<void>(any), ...);
   }
 };
 
diff --git a/sample/kf_2x1x1_rocket_altitude.cpp b/sample/kf_2x1x1_rocket_altitude.cpp
index 1c36f469b..5c066f94b 100644
--- a/sample/kf_2x1x1_rocket_altitude.cpp
+++ b/sample/kf_2x1x1_rocket_altitude.cpp
@@ -69,20 +69,18 @@ template <typename Type, auto Size> using vector = Eigen::Vector<Type, Size>;
   // the system random acceleration. The accelerometer error v is much lower
   // than system's random acceleration, therefore we use ϵ^2 as a multiplier of
   // the process noise matrix. This makes our estimation uncertainty much lower!
-  filter.q(
-      [](const kalman::state &x, const std::chrono::milliseconds &delta_time) {
-        static_cast<void>(x);
-        const auto dt{std::chrono::duration<double>(delta_time).count()};
-        return kalman::process_uncertainty{
-            {0.1 * 0.1 * dt * dt * dt * dt / 4, 0.1 * 0.1 * dt * dt * dt / 2},
-            {0.1 * 0.1 * dt * dt * dt / 2, 0.1 * 0.1 * dt * dt}};
-      });
+  filter.q([]([[maybe_unused]] const kalman::state &x,
+              const std::chrono::milliseconds &delta_time) {
+    const auto dt{std::chrono::duration<double>(delta_time).count()};
+    return kalman::process_uncertainty{
+        {0.1 * 0.1 * dt * dt * dt * dt / 4, 0.1 * 0.1 * dt * dt * dt / 2},
+        {0.1 * 0.1 * dt * dt * dt / 2, 0.1 * 0.1 * dt * dt}};
+  });
 
   // The state transition matrix F would be:
-  filter.f([](const kalman::state &x, const kalman::input &u,
+  filter.f([]([[maybe_unused]] const kalman::state &x,
+              [[maybe_unused]] const kalman::input &u,
               const std::chrono::milliseconds &delta_time) {
-    static_cast<void>(x);
-    static_cast<void>(u);
     const auto dt{std::chrono::duration<double>(delta_time).count()};
     return kalman::state_transition{{1, dt}, {0, 1}};
   });
diff --git a/sample/kf_8x4x0_deep_sort_bounding_box.cpp b/sample/kf_8x4x0_deep_sort_bounding_box.cpp
index 5b1f0d127..3a643f85d 100644
--- a/sample/kf_8x4x0_deep_sort_bounding_box.cpp
+++ b/sample/kf_8x4x0_deep_sort_bounding_box.cpp
@@ -215,17 +215,16 @@ struct divide final {
                                 {0, 0, 0, 1, 0, 0, 0, 0}});
 
   // Observation, measurement noise covariance.
-  filter.r(
-      [position_weight](const kalman::state &x,
-                        const kalman::output &z) -> kalman::output_uncertainty {
-        static_cast<void>(z);
-        return vector<float, 4>{position_weight * x(3), position_weight * x(3),
-                                1e-1f, position_weight * x(3)}
-            .array()
-            .square()
-            .matrix()
-            .asDiagonal();
-      });
+  filter.r([position_weight](const kalman::state &x,
+                             [[maybe_unused]] const kalman::output &z)
+               -> kalman::output_uncertainty {
+    return vector<float, 4>{position_weight * x(3), position_weight * x(3),
+                            1e-1f, position_weight * x(3)}
+        .array()
+        .square()
+        .matrix()
+        .asDiagonal();
+  });
 
   // And so on, run a step of the filter, updating and predicting, every frame.
   for (const auto &output : measured) {
diff --git a/test/eigen_f.cpp b/test/eigen_f.cpp
index d032b3e16..18c928a3f 100644
--- a/test/eigen_f.cpp
+++ b/test/eigen_f.cpp
@@ -107,16 +107,13 @@ struct divide final {
   }
 
   {
-    const auto f{[](const kalman::state &x, const kalman::input &u,
-                    const int &i, const float &fp,
-                    const double &d) -> kalman::state_transition {
-      static_cast<void>(x);
-      static_cast<void>(d);
-      static_cast<void>(fp);
-      static_cast<void>(i);
-      static_cast<void>(u);
-      return matrix<double, 5, 5>::Identity();
-    }};
+    const auto f{
+        []([[maybe_unused]] const kalman::state &x,
+           [[maybe_unused]] const kalman::input &u,
+           [[maybe_unused]] const int &i, [[maybe_unused]] const float &fp,
+           [[maybe_unused]] const double &d) -> kalman::state_transition {
+          return matrix<double, 5, 5>::Identity();
+        }};
     filter.f(f);
     assert(filter.f() == z5x5);
     filter.predict(0, 0.f, 0., z3);
@@ -124,16 +121,13 @@ struct divide final {
   }
 
   {
-    const auto f{[](const kalman::state &x, const kalman::input &u,
-                    const int &i, const float &fp,
-                    const double &d) -> kalman::state_transition {
-      static_cast<void>(x);
-      static_cast<void>(d);
-      static_cast<void>(fp);
-      static_cast<void>(i);
-      static_cast<void>(u);
-      return matrix<double, 5, 5>::Zero();
-    }};
+    const auto f{
+        []([[maybe_unused]] const kalman::state &x,
+           [[maybe_unused]] const kalman::input &u,
+           [[maybe_unused]] const int &i, [[maybe_unused]] const float &fp,
+           [[maybe_unused]] const double &d) -> kalman::state_transition {
+          return matrix<double, 5, 5>::Zero();
+        }};
     filter.f(std::move(f));
     assert(filter.f() == i5x5);
     filter.predict(0, 0.f, 0., z3);
diff --git a/test/eigen_h.cpp b/test/eigen_h.cpp
index 3d4c9fbb5..a0e7b73ea 100644
--- a/test/eigen_h.cpp
+++ b/test/eigen_h.cpp
@@ -106,12 +106,10 @@ struct divide final {
   }
 
   {
-    const auto h{[](const kalman::state &x, const double &d, const float &f,
-                    const int &i) -> kalman::output_model {
-      static_cast<void>(x);
-      static_cast<void>(d);
-      static_cast<void>(f);
-      static_cast<void>(i);
+    const auto h{[]([[maybe_unused]] const kalman::state &x,
+                    [[maybe_unused]] const double &d,
+                    [[maybe_unused]] const float &f,
+                    [[maybe_unused]] const int &i) -> kalman::output_model {
       return matrix<double, 4, 5>::Identity();
     }};
     filter.h(h);
@@ -121,12 +119,10 @@ struct divide final {
   }
 
   {
-    const auto h{[](const kalman::state &x, const double &d, const float &f,
-                    const int &i) -> kalman::output_model {
-      static_cast<void>(x);
-      static_cast<void>(d);
-      static_cast<void>(f);
-      static_cast<void>(i);
+    const auto h{[]([[maybe_unused]] const kalman::state &x,
+                    [[maybe_unused]] const double &d,
+                    [[maybe_unused]] const float &f,
+                    [[maybe_unused]] const int &i) -> kalman::output_model {
       return matrix<double, 4, 5>::Zero();
     }};
     filter.h(std::move(h));
diff --git a/test/f.cpp b/test/f.cpp
index 89cc13f4d..7be99c08c 100644
--- a/test/f.cpp
+++ b/test/f.cpp
@@ -75,10 +75,8 @@ namespace {
   }
 
   {
-    const auto f{[](const kalman::state &x) -> kalman::state_transition {
-      static_cast<void>(x);
-      return 6.;
-    }};
+    const auto f{[]([[maybe_unused]] const kalman::state &x)
+                     -> kalman::state_transition { return 6.; }};
     filter.f(f);
     assert(filter.f() == 5);
     filter.predict();
@@ -86,10 +84,8 @@ namespace {
   }
 
   {
-    const auto f{[](const kalman::state &x) -> kalman::state_transition {
-      static_cast<void>(x);
-      return 7.;
-    }};
+    const auto f{[]([[maybe_unused]] const kalman::state &x)
+                     -> kalman::state_transition { return 7.; }};
     filter.f(std::move(f));
     assert(filter.f() == 6);
     filter.predict();
diff --git a/test/h.cpp b/test/h.cpp
index 7538f57a4..90d936a17 100644
--- a/test/h.cpp
+++ b/test/h.cpp
@@ -75,10 +75,10 @@ namespace {
   }
 
   {
-    const auto h{[](const kalman::state &x) -> kalman::output_model {
-      static_cast<void>(x);
-      return 6.;
-    }};
+    const auto h{
+        []([[maybe_unused]] const kalman::state &x) -> kalman::output_model {
+          return 6.;
+        }};
     filter.h(h);
     assert(filter.h() == 5);
     filter.update(0.);
@@ -86,10 +86,10 @@ namespace {
   }
 
   {
-    const auto h{[](const kalman::state &x) -> kalman::output_model {
-      static_cast<void>(x);
-      return 7.;
-    }};
+    const auto h{
+        []([[maybe_unused]] const kalman::state &x) -> kalman::output_model {
+          return 7.;
+        }};
     filter.h(std::move(h));
     assert(filter.h() == 6);
     filter.update(0.);