From 0522bae972c56fa5a57ce7f28f3536576eeacba7 Mon Sep 17 00:00:00 2001
From: Mateusz Pusz <mateusz.pusz@gmail.com>
Date: Wed, 11 May 2022 11:40:19 +0200
Subject: [PATCH] refactor: :boom: ! `unit` renamed to `derived_unit`

---
 src/core/include/units/unit.h                 | 30 +++++++++----------
 .../units/isq/iec80000/transfer_rate.h        |  2 +-
 .../si-cgs/include/units/isq/si/cgs/power.h   |  2 +-
 .../si-cgs/include/units/isq/si/cgs/speed.h   |  2 +-
 .../include/units/isq/si/fps/acceleration.h   |  2 +-
 .../si-fps/include/units/isq/si/fps/area.h    |  2 +-
 .../si-fps/include/units/isq/si/fps/density.h |  2 +-
 .../si-fps/include/units/isq/si/fps/energy.h  |  2 +-
 .../si-fps/include/units/isq/si/fps/power.h   |  2 +-
 .../include/units/isq/si/fps/pressure.h       |  2 +-
 .../si-fps/include/units/isq/si/fps/speed.h   |  2 +-
 .../si-fps/include/units/isq/si/fps/volume.h  |  2 +-
 .../include/units/isq/si/hep/momentum.h       |  2 +-
 .../si/include/units/isq/si/acceleration.h    |  2 +-
 src/systems/si/include/units/isq/si/area.h    |  2 +-
 .../si/include/units/isq/si/charge_density.h  |  4 +--
 .../si/include/units/isq/si/concentration.h   |  2 +-
 .../si/include/units/isq/si/current_density.h |  2 +-
 src/systems/si/include/units/isq/si/density.h |  2 +-
 .../include/units/isq/si/dynamic_viscosity.h  |  2 +-
 .../units/isq/si/electric_field_strength.h    |  2 +-
 .../si/include/units/isq/si/energy_density.h  |  2 +-
 .../si/include/units/isq/si/heat_capacity.h   |  6 ++--
 .../si/include/units/isq/si/luminance.h       |  2 +-
 .../si/include/units/isq/si/molar_energy.h    |  2 +-
 .../si/include/units/isq/si/momentum.h        |  2 +-
 .../si/include/units/isq/si/permeability.h    |  2 +-
 .../si/include/units/isq/si/permittivity.h    |  2 +-
 src/systems/si/include/units/isq/si/speed.h   |  2 +-
 .../si/include/units/isq/si/surface_tension.h |  2 +-
 .../units/isq/si/thermal_conductivity.h       |  2 +-
 src/systems/si/include/units/isq/si/torque.h  |  2 +-
 src/systems/si/include/units/isq/si/volume.h  |  2 +-
 test/unit_test/static/custom_unit_test.cpp    |  6 ++--
 test/unit_test/static/unit_test.cpp           |  2 +-
 35 files changed, 54 insertions(+), 54 deletions(-)

diff --git a/src/core/include/units/unit.h b/src/core/include/units/unit.h
index 278c9c7c..f2faf55d 100644
--- a/src/core/include/units/unit.h
+++ b/src/core/include/units/unit.h
@@ -65,20 +65,6 @@ using downcast_unit = downcast<scaled_unit<R, typename dimension_unit<D>::refere
 template<Unit U1, Unit U2>
 struct same_unit_reference : is_same<typename U1::reference, typename U2::reference> {};
 
-/**
- * @brief An unnamed unit
- *
- * Defines a new unnamed (in most cases coherent) derived unit of a specific derived dimension
- * and it should be passed in this dimension's definition.
- *
- * @tparam Child inherited class type used by the downcasting facility (CRTP Idiom)
- */
-template<typename Child>
-struct unit : downcast_dispatch<Child, scaled_unit<ratio(1), Child>> {
-  static constexpr bool is_named = false;
-  using prefix_family = no_prefix;
-};
-
 /**
  * @brief A named unit
  *
@@ -139,6 +125,20 @@ struct prefixed_unit : downcast_dispatch<Child, scaled_unit<P::ratio * U::ratio,
   using prefix_family = no_prefix;
 };
 
+/**
+ * @brief A coherent unit of a derived quantity
+ *
+ * Defines a new coherent unit of a derived quantity. It should be passed as a coherent unit
+ * in the dimension's definition for such a quantity.
+ *
+ * @tparam Child inherited class type used by the downcasting facility (CRTP Idiom)
+ */
+template<typename Child>
+struct derived_unit : downcast_dispatch<Child, scaled_unit<ratio(1), Child>> {
+  static constexpr bool is_named = false;
+  using prefix_family = no_prefix;
+};
+
 /**
  * @brief A unit with a deduced ratio and symbol
  *
@@ -209,6 +209,6 @@ struct prefixed_alias_unit : U {
  *
  * Used as a coherent unit of an unknown dimension.
  */
-struct unknown_coherent_unit : unit<unknown_coherent_unit> {};
+struct unknown_coherent_unit : derived_unit<unknown_coherent_unit> {};
 
 }  // namespace units
diff --git a/src/systems/isq-iec80000/include/units/isq/iec80000/transfer_rate.h b/src/systems/isq-iec80000/include/units/isq/iec80000/transfer_rate.h
index 0cd87928..ce22f0f3 100644
--- a/src/systems/isq-iec80000/include/units/isq/iec80000/transfer_rate.h
+++ b/src/systems/isq-iec80000/include/units/isq/iec80000/transfer_rate.h
@@ -34,7 +34,7 @@
 
 namespace units::isq::iec80000 {
 
-struct byte_per_second : unit<byte_per_second> {};
+struct byte_per_second : derived_unit<byte_per_second> {};
 struct dim_transfer_rate :
     derived_dimension<dim_transfer_rate, byte_per_second, exponent<dim_storage_capacity, 1>,
                       exponent<si::dim_time, -1>> {};
diff --git a/src/systems/si-cgs/include/units/isq/si/cgs/power.h b/src/systems/si-cgs/include/units/isq/si/cgs/power.h
index 1ac322f6..5d2b0483 100644
--- a/src/systems/si-cgs/include/units/isq/si/cgs/power.h
+++ b/src/systems/si-cgs/include/units/isq/si/cgs/power.h
@@ -34,7 +34,7 @@
 
 namespace units::isq::si::cgs {
 
-struct erg_per_second : unit<erg_per_second> {};
+struct erg_per_second : derived_unit<erg_per_second> {};
 
 struct dim_power : isq::dim_power<dim_power, erg_per_second, dim_energy, dim_time> {};
 
diff --git a/src/systems/si-cgs/include/units/isq/si/cgs/speed.h b/src/systems/si-cgs/include/units/isq/si/cgs/speed.h
index 6cdc4a7d..c70ee197 100644
--- a/src/systems/si-cgs/include/units/isq/si/cgs/speed.h
+++ b/src/systems/si-cgs/include/units/isq/si/cgs/speed.h
@@ -34,7 +34,7 @@
 
 namespace units::isq::si::cgs {
 
-struct centimetre_per_second : unit<centimetre_per_second> {};
+struct centimetre_per_second : derived_unit<centimetre_per_second> {};
 struct dim_speed : isq::dim_speed<dim_speed, centimetre_per_second, dim_length, dim_time> {};
 
 template<UnitOf<dim_speed> U, Representation Rep = double>
diff --git a/src/systems/si-fps/include/units/isq/si/fps/acceleration.h b/src/systems/si-fps/include/units/isq/si/fps/acceleration.h
index 97990439..da1c9593 100644
--- a/src/systems/si-fps/include/units/isq/si/fps/acceleration.h
+++ b/src/systems/si-fps/include/units/isq/si/fps/acceleration.h
@@ -33,7 +33,7 @@
 
 namespace units::isq::si::fps {
 
-struct foot_per_second_sq : unit<foot_per_second_sq> {};
+struct foot_per_second_sq : derived_unit<foot_per_second_sq> {};
 struct dim_acceleration : isq::dim_acceleration<dim_acceleration, foot_per_second_sq, dim_length, dim_time> {};
 
 template<UnitOf<dim_acceleration> U, Representation Rep = double>
diff --git a/src/systems/si-fps/include/units/isq/si/fps/area.h b/src/systems/si-fps/include/units/isq/si/fps/area.h
index acafd67f..076dab96 100644
--- a/src/systems/si-fps/include/units/isq/si/fps/area.h
+++ b/src/systems/si-fps/include/units/isq/si/fps/area.h
@@ -34,7 +34,7 @@
 
 namespace units::isq::si::fps {
 
-struct square_foot : unit<square_foot> {};
+struct square_foot : derived_unit<square_foot> {};
 struct dim_area : isq::dim_area<dim_area, square_foot, dim_length> {};
 
 
diff --git a/src/systems/si-fps/include/units/isq/si/fps/density.h b/src/systems/si-fps/include/units/isq/si/fps/density.h
index f2aa0e65..41ee340e 100644
--- a/src/systems/si-fps/include/units/isq/si/fps/density.h
+++ b/src/systems/si-fps/include/units/isq/si/fps/density.h
@@ -34,7 +34,7 @@
 
 namespace units::isq::si::fps {
 
-struct pound_per_foot_cub : unit<pound_per_foot_cub> {};
+struct pound_per_foot_cub : derived_unit<pound_per_foot_cub> {};
 
 struct dim_density : isq::dim_density<dim_density, pound_per_foot_cub, dim_mass, dim_length> {};
 
diff --git a/src/systems/si-fps/include/units/isq/si/fps/energy.h b/src/systems/si-fps/include/units/isq/si/fps/energy.h
index f0f69c65..94bdac0d 100644
--- a/src/systems/si-fps/include/units/isq/si/fps/energy.h
+++ b/src/systems/si-fps/include/units/isq/si/fps/energy.h
@@ -35,7 +35,7 @@
 namespace units::isq::si::fps {
 
 // https://en.wikipedia.org/wiki/Foot-poundal
-struct foot_poundal : unit<foot_poundal> {};
+struct foot_poundal : derived_unit<foot_poundal> {};
 
 struct dim_energy : isq::dim_energy<dim_energy, foot_poundal, dim_length, dim_force> {};
 
diff --git a/src/systems/si-fps/include/units/isq/si/fps/power.h b/src/systems/si-fps/include/units/isq/si/fps/power.h
index 37fe6ff7..d168ac6d 100644
--- a/src/systems/si-fps/include/units/isq/si/fps/power.h
+++ b/src/systems/si-fps/include/units/isq/si/fps/power.h
@@ -35,7 +35,7 @@
 
 namespace units::isq::si::fps {
 
-struct foot_poundal_per_second : unit<foot_poundal_per_second> {};
+struct foot_poundal_per_second : derived_unit<foot_poundal_per_second> {};
 
 struct dim_power : isq::dim_power<dim_power, foot_poundal_per_second, dim_length, dim_force, dim_time> {};
 
diff --git a/src/systems/si-fps/include/units/isq/si/fps/pressure.h b/src/systems/si-fps/include/units/isq/si/fps/pressure.h
index 2c87269f..84658252 100644
--- a/src/systems/si-fps/include/units/isq/si/fps/pressure.h
+++ b/src/systems/si-fps/include/units/isq/si/fps/pressure.h
@@ -36,7 +36,7 @@
 
 namespace units::isq::si::fps {
 
-struct poundal_per_foot_sq : unit<poundal_per_foot_sq> {};
+struct poundal_per_foot_sq : derived_unit<poundal_per_foot_sq> {};
 
 struct dim_pressure : isq::dim_pressure<dim_pressure, poundal_per_foot_sq, dim_force, dim_area> {};
 
diff --git a/src/systems/si-fps/include/units/isq/si/fps/speed.h b/src/systems/si-fps/include/units/isq/si/fps/speed.h
index a2577253..0fb4fbb4 100644
--- a/src/systems/si-fps/include/units/isq/si/fps/speed.h
+++ b/src/systems/si-fps/include/units/isq/si/fps/speed.h
@@ -35,7 +35,7 @@
 
 namespace units::isq::si::fps {
 
-struct foot_per_second : unit<foot_per_second> {};
+struct foot_per_second : derived_unit<foot_per_second> {};
 struct dim_speed : isq::dim_speed<dim_speed, foot_per_second, dim_length, dim_time> {};
 
 template<UnitOf<dim_speed> U, Representation Rep = double>
diff --git a/src/systems/si-fps/include/units/isq/si/fps/volume.h b/src/systems/si-fps/include/units/isq/si/fps/volume.h
index b7b813a6..c1ca9c72 100644
--- a/src/systems/si-fps/include/units/isq/si/fps/volume.h
+++ b/src/systems/si-fps/include/units/isq/si/fps/volume.h
@@ -34,7 +34,7 @@
 
 namespace units::isq::si::fps {
 
-struct cubic_foot : unit<cubic_foot> {};
+struct cubic_foot : derived_unit<cubic_foot> {};
 struct dim_volume : isq::dim_volume<dim_volume, cubic_foot, dim_length> {};
 
 struct cubic_yard : derived_deduced_unit<cubic_yard, dim_volume, yard> {};
diff --git a/src/systems/si-hep/include/units/isq/si/hep/momentum.h b/src/systems/si-hep/include/units/isq/si/hep/momentum.h
index 74a85390..26417868 100644
--- a/src/systems/si-hep/include/units/isq/si/hep/momentum.h
+++ b/src/systems/si-hep/include/units/isq/si/hep/momentum.h
@@ -34,7 +34,7 @@
 
 namespace units::isq::si::hep {
 
-struct kilogram_metre_per_second : unit<kilogram_metre_per_second> {};
+struct kilogram_metre_per_second : derived_unit<kilogram_metre_per_second> {};
 
 struct eV_per_c :
     named_scaled_unit<eV_per_c, "eV/c", prefix, ratio(5'344'285'992'678, 1'000'000'000'000, -35),
diff --git a/src/systems/si/include/units/isq/si/acceleration.h b/src/systems/si/include/units/isq/si/acceleration.h
index 313c1df5..90f0168a 100644
--- a/src/systems/si/include/units/isq/si/acceleration.h
+++ b/src/systems/si/include/units/isq/si/acceleration.h
@@ -33,7 +33,7 @@
 
 namespace units::isq::si {
 
-struct metre_per_second_sq : unit<metre_per_second_sq> {};
+struct metre_per_second_sq : derived_unit<metre_per_second_sq> {};
 struct dim_acceleration : isq::dim_acceleration<dim_acceleration, metre_per_second_sq, dim_length, dim_time> {};
 
 template<UnitOf<dim_acceleration> U, Representation Rep = double>
diff --git a/src/systems/si/include/units/isq/si/area.h b/src/systems/si/include/units/isq/si/area.h
index cd6efb2b..a3818096 100644
--- a/src/systems/si/include/units/isq/si/area.h
+++ b/src/systems/si/include/units/isq/si/area.h
@@ -34,7 +34,7 @@
 
 namespace units::isq::si {
 
-struct square_metre : unit<square_metre> {};
+struct square_metre : derived_unit<square_metre> {};
 struct dim_area : isq::dim_area<dim_area, square_metre, dim_length> {};
 
 struct square_yoctometre : derived_deduced_unit<square_yoctometre, dim_area, yoctometre> {};
diff --git a/src/systems/si/include/units/isq/si/charge_density.h b/src/systems/si/include/units/isq/si/charge_density.h
index b50d0c03..52fba248 100644
--- a/src/systems/si/include/units/isq/si/charge_density.h
+++ b/src/systems/si/include/units/isq/si/charge_density.h
@@ -35,8 +35,8 @@
 
 namespace units::isq::si {
 
-struct coulomb_per_metre_cub : unit<coulomb_per_metre_cub> {};
-struct coulomb_per_metre_sq : unit<coulomb_per_metre_sq> {};
+struct coulomb_per_metre_cub : derived_unit<coulomb_per_metre_cub> {};
+struct coulomb_per_metre_sq : derived_unit<coulomb_per_metre_sq> {};
 
 struct dim_charge_density :
     isq::dim_charge_density<dim_charge_density, coulomb_per_metre_cub, dim_electric_charge, dim_length> {};
diff --git a/src/systems/si/include/units/isq/si/concentration.h b/src/systems/si/include/units/isq/si/concentration.h
index d59b3143..732583a5 100644
--- a/src/systems/si/include/units/isq/si/concentration.h
+++ b/src/systems/si/include/units/isq/si/concentration.h
@@ -34,7 +34,7 @@
 
 namespace units::isq::si {
 
-struct mol_per_metre_cub : unit<mol_per_metre_cub> {};
+struct mol_per_metre_cub : derived_unit<mol_per_metre_cub> {};
 struct dim_concentration :
     isq::dim_concentration<dim_concentration, mol_per_metre_cub, dim_amount_of_substance, dim_length> {};
 
diff --git a/src/systems/si/include/units/isq/si/current_density.h b/src/systems/si/include/units/isq/si/current_density.h
index 4017414c..94234b5b 100644
--- a/src/systems/si/include/units/isq/si/current_density.h
+++ b/src/systems/si/include/units/isq/si/current_density.h
@@ -35,7 +35,7 @@
 
 namespace units::isq::si {
 
-struct ampere_per_metre_sq : unit<ampere_per_metre_sq> {};
+struct ampere_per_metre_sq : derived_unit<ampere_per_metre_sq> {};
 
 struct dim_current_density :
     isq::dim_current_density<dim_current_density, ampere_per_metre_sq, dim_electric_current, dim_length> {};
diff --git a/src/systems/si/include/units/isq/si/density.h b/src/systems/si/include/units/isq/si/density.h
index 9a06b479..d890e225 100644
--- a/src/systems/si/include/units/isq/si/density.h
+++ b/src/systems/si/include/units/isq/si/density.h
@@ -35,7 +35,7 @@
 
 namespace units::isq::si {
 
-struct kilogram_per_metre_cub : unit<kilogram_per_metre_cub> {};
+struct kilogram_per_metre_cub : derived_unit<kilogram_per_metre_cub> {};
 
 struct dim_density : isq::dim_density<dim_density, kilogram_per_metre_cub, dim_mass, dim_length> {};
 
diff --git a/src/systems/si/include/units/isq/si/dynamic_viscosity.h b/src/systems/si/include/units/isq/si/dynamic_viscosity.h
index 763eb66c..81f0d2bb 100644
--- a/src/systems/si/include/units/isq/si/dynamic_viscosity.h
+++ b/src/systems/si/include/units/isq/si/dynamic_viscosity.h
@@ -34,7 +34,7 @@
 
 namespace units::isq::si {
 
-struct pascal_second : unit<pascal_second> {};
+struct pascal_second : derived_unit<pascal_second> {};
 struct dim_dynamic_viscosity :
     isq::dim_dynamic_viscosity<dim_dynamic_viscosity, pascal_second, dim_pressure, dim_time> {};
 
diff --git a/src/systems/si/include/units/isq/si/electric_field_strength.h b/src/systems/si/include/units/isq/si/electric_field_strength.h
index 49e843f7..773640d5 100644
--- a/src/systems/si/include/units/isq/si/electric_field_strength.h
+++ b/src/systems/si/include/units/isq/si/electric_field_strength.h
@@ -33,7 +33,7 @@
 
 namespace units::isq::si {
 
-struct volt_per_metre : unit<volt_per_metre> {};
+struct volt_per_metre : derived_unit<volt_per_metre> {};
 struct dim_electric_field_strength :
     isq::dim_electric_field_strength<dim_electric_field_strength, volt_per_metre, dim_voltage, dim_length> {};
 
diff --git a/src/systems/si/include/units/isq/si/energy_density.h b/src/systems/si/include/units/isq/si/energy_density.h
index 3e4e501e..e9e156d7 100644
--- a/src/systems/si/include/units/isq/si/energy_density.h
+++ b/src/systems/si/include/units/isq/si/energy_density.h
@@ -34,7 +34,7 @@
 
 namespace units::isq::si {
 
-struct joule_per_metre_cub : unit<joule_per_metre_cub> {};
+struct joule_per_metre_cub : derived_unit<joule_per_metre_cub> {};
 struct dim_energy_density : isq::dim_energy_density<dim_energy_density, joule_per_metre_cub, dim_energy, dim_volume> {};
 
 template<UnitOf<dim_energy_density> U, Representation Rep = double>
diff --git a/src/systems/si/include/units/isq/si/heat_capacity.h b/src/systems/si/include/units/isq/si/heat_capacity.h
index b264f59d..5ae30cfa 100644
--- a/src/systems/si/include/units/isq/si/heat_capacity.h
+++ b/src/systems/si/include/units/isq/si/heat_capacity.h
@@ -36,9 +36,9 @@
 
 namespace units::isq::si {
 
-struct joule_per_kelvin : unit<joule_per_kelvin> {};
-struct joule_per_kilogram_kelvin : unit<joule_per_kilogram_kelvin> {};
-struct joule_per_mole_kelvin : unit<joule_per_mole_kelvin> {};
+struct joule_per_kelvin : derived_unit<joule_per_kelvin> {};
+struct joule_per_kilogram_kelvin : derived_unit<joule_per_kilogram_kelvin> {};
+struct joule_per_mole_kelvin : derived_unit<joule_per_mole_kelvin> {};
 
 struct dim_heat_capacity :
     isq::dim_heat_capacity<dim_heat_capacity, joule_per_kelvin, dim_energy, dim_thermodynamic_temperature> {};
diff --git a/src/systems/si/include/units/isq/si/luminance.h b/src/systems/si/include/units/isq/si/luminance.h
index d6c6b74f..48f01073 100644
--- a/src/systems/si/include/units/isq/si/luminance.h
+++ b/src/systems/si/include/units/isq/si/luminance.h
@@ -34,7 +34,7 @@
 
 namespace units::isq::si {
 
-struct candela_per_metre_sq : unit<candela_per_metre_sq> {};
+struct candela_per_metre_sq : derived_unit<candela_per_metre_sq> {};
 struct dim_luminance : isq::dim_luminance<dim_luminance, candela_per_metre_sq, dim_luminous_intensity, dim_length> {};
 
 template<UnitOf<dim_luminance> U, Representation Rep = double>
diff --git a/src/systems/si/include/units/isq/si/molar_energy.h b/src/systems/si/include/units/isq/si/molar_energy.h
index fa4cae49..02cb9072 100644
--- a/src/systems/si/include/units/isq/si/molar_energy.h
+++ b/src/systems/si/include/units/isq/si/molar_energy.h
@@ -35,7 +35,7 @@
 
 namespace units::isq::si {
 
-struct joule_per_mole : unit<joule_per_mole> {};
+struct joule_per_mole : derived_unit<joule_per_mole> {};
 
 struct dim_molar_energy :
     isq::dim_molar_energy<dim_molar_energy, joule_per_mole, dim_energy, dim_amount_of_substance> {};
diff --git a/src/systems/si/include/units/isq/si/momentum.h b/src/systems/si/include/units/isq/si/momentum.h
index f4605e88..46446c92 100644
--- a/src/systems/si/include/units/isq/si/momentum.h
+++ b/src/systems/si/include/units/isq/si/momentum.h
@@ -34,7 +34,7 @@
 
 namespace units::isq::si {
 
-struct kilogram_metre_per_second : unit<kilogram_metre_per_second> {};
+struct kilogram_metre_per_second : derived_unit<kilogram_metre_per_second> {};
 struct dim_momentum : isq::dim_momentum<dim_momentum, kilogram_metre_per_second, dim_mass, dim_speed> {};
 
 template<UnitOf<dim_momentum> U, Representation Rep = double>
diff --git a/src/systems/si/include/units/isq/si/permeability.h b/src/systems/si/include/units/isq/si/permeability.h
index 2cb04734..5b961b21 100644
--- a/src/systems/si/include/units/isq/si/permeability.h
+++ b/src/systems/si/include/units/isq/si/permeability.h
@@ -34,7 +34,7 @@
 
 namespace units::isq::si {
 
-struct henry_per_metre : unit<henry_per_metre> {};
+struct henry_per_metre : derived_unit<henry_per_metre> {};
 
 struct dim_permeability : isq::dim_permeability<dim_permeability, henry_per_metre, dim_inductance, dim_length> {};
 
diff --git a/src/systems/si/include/units/isq/si/permittivity.h b/src/systems/si/include/units/isq/si/permittivity.h
index bb6b1953..cd99be6c 100644
--- a/src/systems/si/include/units/isq/si/permittivity.h
+++ b/src/systems/si/include/units/isq/si/permittivity.h
@@ -34,7 +34,7 @@
 
 namespace units::isq::si {
 
-struct farad_per_metre : unit<farad_per_metre> {};
+struct farad_per_metre : derived_unit<farad_per_metre> {};
 
 struct dim_permittivity : isq::dim_permittivity<dim_permittivity, farad_per_metre, dim_capacitance, dim_length> {};
 
diff --git a/src/systems/si/include/units/isq/si/speed.h b/src/systems/si/include/units/isq/si/speed.h
index ddb022cd..a2c3adc0 100644
--- a/src/systems/si/include/units/isq/si/speed.h
+++ b/src/systems/si/include/units/isq/si/speed.h
@@ -34,7 +34,7 @@
 
 namespace units::isq::si {
 
-struct metre_per_second : unit<metre_per_second> {};
+struct metre_per_second : derived_unit<metre_per_second> {};
 struct dim_speed : isq::dim_speed<dim_speed, metre_per_second, dim_length, dim_time> {};
 
 struct kilometre_per_hour : derived_deduced_unit<kilometre_per_hour, dim_speed, kilometre, hour> {};
diff --git a/src/systems/si/include/units/isq/si/surface_tension.h b/src/systems/si/include/units/isq/si/surface_tension.h
index 87b02a2c..382b133f 100644
--- a/src/systems/si/include/units/isq/si/surface_tension.h
+++ b/src/systems/si/include/units/isq/si/surface_tension.h
@@ -33,7 +33,7 @@
 
 namespace units::isq::si {
 
-struct newton_per_metre : unit<newton_per_metre> {};
+struct newton_per_metre : derived_unit<newton_per_metre> {};
 
 struct dim_surface_tension : isq::dim_surface_tension<dim_surface_tension, newton_per_metre, dim_force, dim_length> {};
 
diff --git a/src/systems/si/include/units/isq/si/thermal_conductivity.h b/src/systems/si/include/units/isq/si/thermal_conductivity.h
index d4a09c9f..64177b52 100644
--- a/src/systems/si/include/units/isq/si/thermal_conductivity.h
+++ b/src/systems/si/include/units/isq/si/thermal_conductivity.h
@@ -34,7 +34,7 @@
 
 namespace units::isq::si {
 
-struct watt_per_metre_kelvin : unit<watt_per_metre_kelvin> {};
+struct watt_per_metre_kelvin : derived_unit<watt_per_metre_kelvin> {};
 
 struct dim_thermal_conductivity :
     isq::dim_thermal_conductivity<dim_thermal_conductivity, watt_per_metre_kelvin, dim_power, dim_length,
diff --git a/src/systems/si/include/units/isq/si/torque.h b/src/systems/si/include/units/isq/si/torque.h
index 1245cf6c..14e5aec2 100644
--- a/src/systems/si/include/units/isq/si/torque.h
+++ b/src/systems/si/include/units/isq/si/torque.h
@@ -35,7 +35,7 @@
 
 namespace units::isq::si {
 
-struct newton_metre_per_radian : unit<newton_metre_per_radian> {};
+struct newton_metre_per_radian : derived_unit<newton_metre_per_radian> {};
 
 struct dim_torque : isq::dim_torque<dim_torque, newton_metre_per_radian, dim_force, dim_length, dim_angle<>> {};
 
diff --git a/src/systems/si/include/units/isq/si/volume.h b/src/systems/si/include/units/isq/si/volume.h
index 6f0dc9b1..a1f77b6e 100644
--- a/src/systems/si/include/units/isq/si/volume.h
+++ b/src/systems/si/include/units/isq/si/volume.h
@@ -34,7 +34,7 @@
 
 namespace units::isq::si {
 
-struct cubic_metre : unit<cubic_metre> {};
+struct cubic_metre : derived_unit<cubic_metre> {};
 struct dim_volume : isq::dim_volume<dim_volume, cubic_metre, dim_length> {};
 
 struct cubic_yoctometre : derived_deduced_unit<cubic_yoctometre, dim_volume, yoctometre> {};
diff --git a/test/unit_test/static/custom_unit_test.cpp b/test/unit_test/static/custom_unit_test.cpp
index 15216be8..bf26b340 100644
--- a/test/unit_test/static/custom_unit_test.cpp
+++ b/test/unit_test/static/custom_unit_test.cpp
@@ -36,7 +36,7 @@ using namespace units;
 using namespace units::isq::si;
 
 // power spectral density
-struct sq_volt_per_hertz : unit<sq_volt_per_hertz> {};
+struct sq_volt_per_hertz : derived_unit<sq_volt_per_hertz> {};
 struct dim_power_spectral_density :
     derived_dimension<dim_power_spectral_density, sq_volt_per_hertz, units::exponent<dim_voltage, 2>,
                       units::exponent<dim_frequency, -1>> {};
@@ -45,7 +45,7 @@ template<UnitOf<dim_power_spectral_density> U, Representation Rep = double>
 using power_spectral_density = quantity<dim_power_spectral_density, U, Rep>;
 
 // amplitude spectral density
-struct volt_per_sqrt_hertz : unit<volt_per_sqrt_hertz> {};
+struct volt_per_sqrt_hertz : derived_unit<volt_per_sqrt_hertz> {};
 struct dim_amplitude_spectral_density :
     derived_dimension<dim_amplitude_spectral_density, volt_per_sqrt_hertz, units::exponent<dim_voltage, 1>,
                       units::exponent<dim_frequency, -1, 2>> {};
@@ -69,7 +69,7 @@ static_assert(compare<decltype(sqrt(power_spectral_density<sq_volt_per_hertz>(16
 
 namespace {
 
-struct kilogram_per_second : unit<kilogram_per_second> {};
+struct kilogram_per_second : derived_unit<kilogram_per_second> {};
 struct dim_mass_rate :
     derived_dimension<dim_mass_rate, kilogram_per_second, units::exponent<dim_mass, 1>, units::exponent<dim_time, -1>> {
 };
diff --git a/test/unit_test/static/unit_test.cpp b/test/unit_test/static/unit_test.cpp
index 059ef739..ddd97b88 100644
--- a/test/unit_test/static/unit_test.cpp
+++ b/test/unit_test/static/unit_test.cpp
@@ -52,7 +52,7 @@ static_assert([]<Prefix P>(P) {
 }(si::kilo{}));  // no prefix allowed
 #endif
 
-struct metre_per_second : unit<metre_per_second> {};
+struct metre_per_second : derived_unit<metre_per_second> {};
 struct dim_speed :
     derived_dimension<dim_speed, metre_per_second, units::exponent<dim_length, 1>, units::exponent<dim_time, -1>> {};
 struct kilometre_per_hour : derived_deduced_unit<kilometre_per_hour, dim_speed, kilometre, hour> {};