diff --git a/docs/users_guide/framework_basics/text_output.md b/docs/users_guide/framework_basics/text_output.md
index de8c96ea..67bd4395 100644
--- a/docs/users_guide/framework_basics/text_output.md
+++ b/docs/users_guide/framework_basics/text_output.md
@@ -48,7 +48,7 @@ and units of derived quantities.
     inline constexpr struct second : named_unit<"s", kind_of<isq::time>> {} second;
     inline constexpr struct metre : named_unit<"m", kind_of<isq::length>> {} metre;
     inline constexpr struct gram : named_unit<"g", kind_of<isq::mass>> {} gram;
-    inline constexpr struct kilogram : decltype(kilo<gram>) {} kilogram;
+    inline constexpr auto kilogram = kilo<gram>;
 
     inline constexpr struct newton : named_unit<"N", kilogram * metre / square(second)> {} newton;
     inline constexpr struct joule : named_unit<"J", newton * metre> {} joule;
diff --git a/src/systems/include/mp-units/systems/cgs.h b/src/systems/include/mp-units/systems/cgs.h
index f3e58e54..4a3645f5 100644
--- a/src/systems/include/mp-units/systems/cgs.h
+++ b/src/systems/include/mp-units/systems/cgs.h
@@ -35,13 +35,9 @@ MP_UNITS_EXPORT
 namespace mp_units::cgs {
 
 // clang-format off
-#if MP_UNITS_COMP_MSVC
-inline constexpr struct centimetre : si::centi_<si::metre> {} centimetre;
-#else
-inline constexpr struct centimetre : decltype(si::centi<si::metre>) {} centimetre;
-#endif
-inline constexpr struct gram : decltype(si::gram) {} gram;
-inline constexpr struct second : decltype(si::second) {} second;
+inline constexpr auto centimetre = si::centi<si::metre>;
+inline constexpr auto gram = si::gram;
+inline constexpr auto second = si::second;
 inline constexpr struct gal : named_unit<"Gal", centimetre / square(second)> {} gal;
 inline constexpr struct dyne : named_unit<"dyn", gram * centimetre / square(second)> {} dyne;
 inline constexpr struct erg : named_unit<"erg", dyne * centimetre> {} erg;
diff --git a/src/systems/include/mp-units/systems/hep.h b/src/systems/include/mp-units/systems/hep.h
index 0267042f..6020d07f 100644
--- a/src/systems/include/mp-units/systems/hep.h
+++ b/src/systems/include/mp-units/systems/hep.h
@@ -57,7 +57,7 @@ inline constexpr struct proton_mass : named_unit<"m_p", mag_ratio<1'672'621'923'
 inline constexpr struct neutron_mass : named_unit<"m_n", mag_ratio<1'674'927'498'049, 1'000'000'000'000> * mag_power<10, -27> * si::kilogram> {} neutron_mass;
 
 // speed
-inline constexpr struct speed_of_light : decltype(si::si2019::speed_of_light_in_vacuum) {} speed_of_light;
+inline constexpr auto speed_of_light = si::si2019::speed_of_light_in_vacuum;
 // clang-format on
 
 namespace unit_symbols {
diff --git a/src/systems/include/mp-units/systems/iau.h b/src/systems/include/mp-units/systems/iau.h
index 8d4aeaa8..804f2ed0 100644
--- a/src/systems/include/mp-units/systems/iau.h
+++ b/src/systems/include/mp-units/systems/iau.h
@@ -50,7 +50,7 @@ inline constexpr struct Jupiter_mass : named_unit<"M_JUP", mag_ratio<1'898, 1'00
 inline constexpr struct Earth_mass : named_unit<"M_EARTH", mag_ratio<59'742, 10'000> * mag_power<10, 24> * si::kilogram> {} Earth_mass;
 
 // length
-inline constexpr struct astronomical_unit : decltype(si::astronomical_unit) {} astronomical_unit;
+inline constexpr auto astronomical_unit = si::astronomical_unit;
 
 // https://en.wikipedia.org/wiki/Lunar_distance_(astronomy)
 inline constexpr struct lunar_distance : named_unit<"LD", mag<384'399> * si::kilo<si::metre>> {} lunar_distance;
diff --git a/src/systems/include/mp-units/systems/imperial.h b/src/systems/include/mp-units/systems/imperial.h
index 4398a8f5..ffdd4002 100644
--- a/src/systems/include/mp-units/systems/imperial.h
+++ b/src/systems/include/mp-units/systems/imperial.h
@@ -54,9 +54,9 @@ inline constexpr struct link : named_unit<"li", mag_ratio<1, 100> * chain> {} li
 inline constexpr struct rod : named_unit<"rd", mag<25> * link> {} rod;
 
 // https://en.wikipedia.org/wiki/Imperial_units#Area
-inline constexpr struct perch : decltype(square(rod)) {} perch;
-inline constexpr struct rood : decltype(mag<40> * perch) {} rood;
-inline constexpr struct acre : decltype(mag<4> * rood) {} acre;
+inline constexpr struct perch : named_unit<"perch", square(rod)> {} perch;
+inline constexpr struct rood : named_unit<"rood", mag<40> * perch> {} rood;
+inline constexpr struct acre : named_unit<"acre", mag<4> * rood> {} acre;
 
 // https://en.wikipedia.org/wiki/Imperial_units#Volume
 inline constexpr struct gallon : named_unit<"gal", mag_ratio<454'609, 100'000> * si::litre> {} gallon;
diff --git a/src/systems/include/mp-units/systems/international.h b/src/systems/include/mp-units/systems/international.h
index 0b680ce3..d4de6a31 100644
--- a/src/systems/include/mp-units/systems/international.h
+++ b/src/systems/include/mp-units/systems/international.h
@@ -67,11 +67,7 @@ inline constexpr struct poundal : named_unit<"pdl", pound * foot / square(si::se
 inline constexpr struct pound_force : named_unit<"lbf", pound * si::standard_gravity> {} pound_force;
 
 // https://en.wikipedia.org/wiki/Kip_(unit),
-#if MP_UNITS_COMP_MSVC
-inline constexpr struct kip : si::kilo_<pound_force> {} kip;
-#else
-inline constexpr struct kip : decltype(si::kilo<pound_force>) {} kip;
-#endif
+inline constexpr auto kip = si::kilo<pound_force>;
 
 // pressure
 inline constexpr struct psi : named_unit<"psi", pound_force / square(inch)> {} psi;
diff --git a/src/systems/include/mp-units/systems/natural.h b/src/systems/include/mp-units/systems/natural.h
index b56ee725..35f63339 100644
--- a/src/systems/include/mp-units/systems/natural.h
+++ b/src/systems/include/mp-units/systems/natural.h
@@ -39,11 +39,7 @@ namespace mp_units::natural {
 // clang-format off
 // units
 inline constexpr struct electronvolt : named_unit<"eV"> {} electronvolt;
-#if MP_UNITS_COMP_MSVC
-inline constexpr struct gigaelectronvolt : si::giga_<electronvolt> {} gigaelectronvolt;
-#else
-inline constexpr struct gigaelectronvolt : decltype(si::giga<electronvolt>) {} gigaelectronvolt;
-#endif
+inline constexpr auto gigaelectronvolt = si::giga<electronvolt>;
 
 // system references
 inline constexpr struct time : system_reference<isq::time, inverse(gigaelectronvolt)> {} time;
diff --git a/src/systems/include/mp-units/systems/si/units.h b/src/systems/include/mp-units/systems/si/units.h
index 36d7772f..72b16ba3 100644
--- a/src/systems/include/mp-units/systems/si/units.h
+++ b/src/systems/include/mp-units/systems/si/units.h
@@ -41,11 +41,7 @@ namespace si {
 inline constexpr struct second : named_unit<"s", kind_of<isq::time>> {} second;
 inline constexpr struct metre : named_unit<"m", kind_of<isq::length>> {} metre;
 inline constexpr struct gram : named_unit<"g", kind_of<isq::mass>> {} gram;
-#if MP_UNITS_COMP_MSVC
-inline constexpr struct kilogram : kilo_<gram> {} kilogram;
-#else
-inline constexpr struct kilogram : decltype(kilo<gram>) {} kilogram;
-#endif
+inline constexpr auto kilogram = kilo<gram>;
 inline constexpr struct ampere : named_unit<"A", kind_of<isq::electric_current>> {} ampere;
 
 inline constexpr struct absolute_zero : absolute_point_origin<absolute_zero, isq::thermodynamic_temperature> {} absolute_zero;
@@ -107,11 +103,7 @@ inline constexpr struct degree : named_unit<symbol_text{u8"°", "deg"}, mag_pi /
 inline constexpr struct arcminute : named_unit<symbol_text{u8"′", "'"}, mag_ratio<1, 60> * degree> {} arcminute;
 inline constexpr struct arcsecond : named_unit<symbol_text{u8"″", "''"}, mag_ratio<1, 60> * arcminute> {} arcsecond;
 inline constexpr struct are : named_unit<"a", square(si::deca<si::metre>)> {} are;
-#if MP_UNITS_COMP_MSVC
-inline constexpr struct hectare : si::hecto_<are> {} hectare;
-#else
-inline constexpr struct hectare : decltype(si::hecto<are>) {} hectare;
-#endif
+inline constexpr auto hectare = si::hecto<are>;
 inline constexpr struct litre : named_unit<"l", cubic(si::deci<si::metre>)> {} litre;
 inline constexpr struct tonne : named_unit<"t", mag<1000> * si::kilogram> {} tonne;
 inline constexpr struct dalton : named_unit<"Da", mag_ratio<16'605'390'666'050, 10'000'000'000'000> * mag_power<10, -27> * si::kilogram> {} dalton;
diff --git a/src/systems/include/mp-units/systems/usc.h b/src/systems/include/mp-units/systems/usc.h
index cfa2eb76..87c7ace5 100644
--- a/src/systems/include/mp-units/systems/usc.h
+++ b/src/systems/include/mp-units/systems/usc.h
@@ -94,7 +94,7 @@ inline constexpr struct minim : named_unit<"min", mag_ratio<1, 80> * teaspoon> {
 inline constexpr struct fluid_dram : named_unit<"fl dr", mag<60> * minim> {} fluid_dram;
 inline constexpr struct barrel : named_unit<"bbl", mag_ratio<315, 10> * gallon> {} barrel;
 inline constexpr struct oil_barrel : named_unit<"bbl", mag_ratio<4, 3> * barrel> {} oil_barrel;
-inline constexpr struct hogshead : decltype(mag<63> * gallon) {} hogshead;
+inline constexpr struct hogshead : named_unit<"hogshead", mag<63> * gallon> {} hogshead;
 
 // https://en.wikipedia.org/wiki/United_States_customary_units#Dry_volume
 inline constexpr struct dry_barrel : named_unit<"bbl", mag<7056> * cubic(inch)> {} dry_barrel;
diff --git a/test/static/concepts_test.cpp b/test/static/concepts_test.cpp
index 68033efa..85e5a58c 100644
--- a/test/static/concepts_test.cpp
+++ b/test/static/concepts_test.cpp
@@ -141,7 +141,7 @@ static_assert(!detail::QuantityKindSpec<int>);
 struct metre_per_second : decltype(si::metre / si::second) {};
 
 static_assert(Unit<struct si::metre>);
-static_assert(Unit<struct si::kilogram>);
+static_assert(Unit<decltype(si::kilogram)>);
 static_assert(Unit<decltype(si::kilo<si::gram>)>);
 static_assert(Unit<struct natural::electronvolt>);
 static_assert(Unit<decltype(si::metre / si::second)>);
@@ -168,7 +168,7 @@ static_assert(!Unit<std::chrono::seconds>);
 // NamedUnit
 static_assert(detail::NamedUnit<struct si::metre>);
 static_assert(detail::NamedUnit<struct natural::electronvolt>);
-static_assert(!detail::NamedUnit<struct si::kilogram>);
+static_assert(!detail::NamedUnit<decltype(si::kilogram)>);
 static_assert(!detail::NamedUnit<decltype(si::kilo<si::gram>)>);
 static_assert(!detail::NamedUnit<decltype(si::metre / si::second)>);
 static_assert(!detail::NamedUnit<decltype(inverse(si::second))>);
@@ -194,7 +194,7 @@ static_assert(!detail::NamedUnit<std::chrono::seconds>);
 // PrefixableUnit
 static_assert(PrefixableUnit<struct si::metre>);
 static_assert(PrefixableUnit<struct natural::electronvolt>);
-static_assert(!PrefixableUnit<struct si::kilogram>);
+static_assert(!PrefixableUnit<decltype(si::kilogram)>);
 static_assert(!PrefixableUnit<decltype(si::kilo<si::gram>)>);
 static_assert(!PrefixableUnit<decltype(si::metre / si::second)>);
 static_assert(!PrefixableUnit<decltype(inverse(si::second))>);
@@ -220,7 +220,7 @@ static_assert(!PrefixableUnit<std::chrono::seconds>);
 // AssociatedUnit
 static_assert(AssociatedUnit<struct si::metre>);
 static_assert(!AssociatedUnit<struct natural::electronvolt>);
-static_assert(AssociatedUnit<struct si::kilogram>);
+static_assert(AssociatedUnit<decltype(si::kilogram)>);
 static_assert(AssociatedUnit<decltype(si::kilo<si::gram>)>);
 static_assert(AssociatedUnit<decltype(si::metre / si::second)>);
 static_assert(AssociatedUnit<decltype(inverse(si::second))>);
@@ -246,7 +246,7 @@ static_assert(!AssociatedUnit<std::chrono::seconds>);
 // UnitOf
 static_assert(UnitOf<struct si::metre, isq::length>);
 static_assert(UnitOf<struct si::metre, isq::radius>);
-static_assert(UnitOf<struct si::kilogram, isq::mass>);
+static_assert(UnitOf<decltype(si::kilogram), isq::mass>);
 static_assert(UnitOf<struct si::hertz, isq::frequency>);
 static_assert(UnitOf<struct si::hertz, inverse(isq::time)>);
 static_assert(UnitOf<struct one, dimensionless>);