refactor: 💥 ReferenceOf does not take a dimension anymore

It seems unneeded and removing this check greatly simplifies common compilation errors.

docs/users_guide/framework_basics/concepts.md

@@ -165,12 +165,8 @@ A `Reference` can either be:
 
 ### `ReferenceOf<T, V>` { #ReferenceOf }
 
-`ReferenceOf` concept is satisfied by references `T` that match the following value `V`:
-
-| `V`            | Condition                                                                                     |
-|----------------|-----------------------------------------------------------------------------------------------|
-| `Dimension`    | The dimension of a quantity specification satisfies [`DimensionOf<V>`](#DimensionOf) concept. |
-| `QuantitySpec` | The quantity specification satisfies [`QuantitySpecOf<V>`](#QuantitySpecOf) concept.          |
+`ReferenceOf` concept is satisfied by references `T` which have a quantity specification that satisfies
+[`QuantitySpecOf<V>`](#QuantitySpecOf) concept.          |
 
 
 ## `Representation<T>` { #Representation }
@@ -212,7 +208,7 @@ satisfied by all types being or deriving from an instantiation of a `quantity` c
 
 ### `QuantityOf<T, V>` { #QuantityOf }
 
-`QuantityOf` concept is satisfied by all the quantities for which a [`ReferenceOf<V>`](#ReferenceOf)
+`QuantityOf` concept is satisfied by all the quantities for which a [`QuantitySpecOf<V>`](#QuantitySpecOf)
 is `true`.
 
 
@@ -259,10 +255,10 @@ class template.
 
 `QuantityPointOf` concept is satisfied by all the quantity points `T` that match the following value `V`:
 
-| `V`           | Condition                                                                        |
-|---------------|----------------------------------------------------------------------------------|
-| `Reference`   | The quantity point reference satisfies [`ReferenceOf<V>`](#ReferenceOf) concept. |
-| `PointOrigin` | The _point_ and `V` have the same absolute point origin.                         |
+| `V`            | Condition                                                                                           |
+|----------------|-----------------------------------------------------------------------------------------------------|
+| `QuantitySpec` | The quantity point quantity specification satisfies [`QuantitySpecOf<V>`](#QuantitySpecOf) concept. |
+| `PointOrigin`  | The _point_ and `V` have the same absolute point origin.                                            |
 
 
 ## `QuantityLike<T>` { #QuantityLike }

src/core/include/mp-units/bits/quantity_concepts.h

@@ -52,13 +52,13 @@ template<typename T>
 concept Quantity = detail::is_derived_from_specialization_of_quantity<T>;
 
 /**
- * @brief A concept matching all quantities with provided dimension or quantity spec
+ * @brief A concept matching all quantities with provided quantity spec
  *
- * Satisfied by all quantities with a dimension/quantity_spec being the instantiation derived from
- * the provided dimension/quantity_spec type.
+ * Satisfied by all quantities with a quantity_spec being the instantiation derived from
+ * the provided quantity_spec type.
  */
-template<typename Q, auto V>
-concept QuantityOf = Quantity<Q> && ReferenceOf<std::remove_const_t<decltype(Q::reference)>, V>;
+template<typename Q, auto QS>
+concept QuantityOf = Quantity<Q> && QuantitySpecOf<std::remove_const_t<decltype(Q::quantity_spec)>, QS>;
 
 /**
  * @brief A concept matching all external quantities like types

src/core/include/mp-units/bits/quantity_point_concepts.h

@@ -145,15 +145,15 @@ concept SameAbsolutePointOriginAs =
 
 
 /**
- * @brief A concept matching all quantity points with provided dimension or quantity spec
+ * @brief A concept matching all quantity points with provided quantity spec
  *
- * Satisfied by all quantity points with a dimension/quantity_spec being the instantiation derived from
- * the provided dimension/quantity_spec type, or quantity points having the origin with the same
+ * Satisfied by all quantity points with a quantity_spec being the instantiation derived from
+ * the provided quantity_spec type, or quantity points having the origin with the same
  * `absolute_point_origin`.
  */
 template<typename QP, auto V>
 concept QuantityPointOf =
-  QuantityPoint<QP> && (ReferenceOf<std::remove_const_t<decltype(QP::reference)>, V> ||
+  QuantityPoint<QP> && (QuantitySpecOf<std::remove_const_t<decltype(QP::quantity_spec)>, V> ||
                         detail::SameAbsolutePointOriginAs<std::remove_const_t<decltype(QP::absolute_point_origin)>, V>);
 
 /**

src/core/include/mp-units/bits/reference_concepts.h

@@ -66,14 +66,12 @@ template<auto Q, auto U>
 }
 
 /**
- * @brief A concept matching all references with provided dimension or quantity spec
+ * @brief A concept matching all references with provided quantity spec
  *
- * Satisfied by all references with a dimension/quantity_spec being the instantiation derived from
- * the provided dimension/quantity_spec type.
+ * Satisfied by all references with a quantity_spec being the instantiation derived from
+ * the provided quantity_spec type.
  */
-template<typename T, auto V>
-concept ReferenceOf =
-  Reference<T> && (DimensionOf<std::remove_const_t<decltype(get_quantity_spec(T{}).dimension)>, V> ||
-                   QuantitySpecOf<std::remove_const_t<decltype(get_quantity_spec(T{}))>, V>);
+template<typename T, auto QS>
+concept ReferenceOf = Reference<T> && QuantitySpecOf<std::remove_const_t<decltype(get_quantity_spec(T{}))>, QS>;
 
 }  // namespace mp_units

test/static/concepts_test.cpp

@@ -82,6 +82,9 @@ static_assert(!Dimension<base_dimension<"L">>);
 static_assert(!Dimension<struct si::metre>);
 static_assert(!Dimension<int>);
 
+// DimensionOf
+// TODO add tests
+
 // QuantitySpec
 struct speed : decltype(isq::length / isq::time) {};  // this is not recommended
 
@@ -132,6 +135,9 @@ static_assert(!detail::QuantityKindSpec<speed>);
 static_assert(!detail::QuantityKindSpec<struct isq::dim_length>);
 static_assert(!detail::QuantityKindSpec<int>);
 
+// QuantitySpecOf
+// TODO add tests
+
 // Unit
 struct metre_per_second : decltype(si::metre / si::second) {};
 
@@ -265,24 +271,16 @@ static_assert(ReferenceOf<std::remove_const_t<decltype(isq::length[si::metre])>,
 static_assert(!ReferenceOf<std::remove_const_t<decltype(isq::length[si::metre])>, isq::radius>);
 static_assert(ReferenceOf<std::remove_const_t<decltype(isq::radius[si::metre])>, isq::length>);
 static_assert(ReferenceOf<std::remove_const_t<decltype(isq::radius[si::metre])>, isq::radius>);
-static_assert(ReferenceOf<struct si::metre, isq::dim_length>);
 static_assert(!ReferenceOf<struct si::second, isq::dim_length>);
-static_assert(ReferenceOf<std::remove_const_t<decltype(isq::length[si::metre])>, isq::dim_length>);
-static_assert(ReferenceOf<std::remove_const_t<decltype(isq::radius[si::metre])>, isq::dim_length>);
 
 static_assert(ReferenceOf<struct one, dimensionless>);
-static_assert(ReferenceOf<struct one, dimension_one>);
 static_assert(ReferenceOf<std::remove_const_t<decltype(dimensionless[one])>, dimensionless>);
-static_assert(ReferenceOf<std::remove_const_t<decltype(dimensionless[one])>, dimension_one>);
 static_assert(ReferenceOf<std::remove_const_t<decltype(isq::rotation[one])>, isq::rotation>);
 static_assert(ReferenceOf<std::remove_const_t<decltype(isq::rotation[one])>, dimensionless>);
-static_assert(ReferenceOf<std::remove_const_t<decltype(isq::rotation[one])>, dimension_one>);
 static_assert(ReferenceOf<struct si::radian, isq::angular_measure>);
 static_assert(!ReferenceOf<struct si::radian, dimensionless>);
-static_assert(ReferenceOf<struct si::radian, dimension_one>);
 static_assert(ReferenceOf<std::remove_const_t<decltype(isq::angular_measure[si::radian])>, isq::angular_measure>);
 static_assert(!ReferenceOf<std::remove_const_t<decltype(isq::angular_measure[si::radian])>, dimensionless>);
-static_assert(ReferenceOf<std::remove_const_t<decltype(isq::angular_measure[si::radian])>, dimension_one>);
 static_assert(ReferenceOf<struct one, isq::rotation>);
 static_assert(ReferenceOf<struct one, isq::angular_measure>);
 static_assert(!ReferenceOf<std::remove_const_t<decltype(dimensionless[one])>, isq::rotation>);
@@ -323,24 +321,16 @@ static_assert(QuantityOf<quantity<isq::length[si::metre]>, isq::length>);
 static_assert(!QuantityOf<quantity<isq::length[si::metre]>, isq::radius>);
 static_assert(QuantityOf<quantity<isq::radius[si::metre]>, isq::length>);
 static_assert(QuantityOf<quantity<isq::radius[si::metre]>, isq::radius>);
-static_assert(QuantityOf<quantity<si::metre>, isq::dim_length>);
 static_assert(!QuantityOf<quantity<si::second>, isq::dim_length>);
-static_assert(QuantityOf<quantity<isq::length[si::metre]>, isq::dim_length>);
-static_assert(QuantityOf<quantity<isq::radius[si::metre]>, isq::dim_length>);
 
 static_assert(QuantityOf<quantity<one>, dimensionless>);
-static_assert(QuantityOf<quantity<one>, dimension_one>);
 static_assert(QuantityOf<quantity<dimensionless[one]>, dimensionless>);
-static_assert(QuantityOf<quantity<dimensionless[one]>, dimension_one>);
 static_assert(QuantityOf<quantity<isq::rotation[one]>, isq::rotation>);
 static_assert(QuantityOf<quantity<isq::rotation[one]>, dimensionless>);
-static_assert(QuantityOf<quantity<isq::rotation[one]>, dimension_one>);
 static_assert(QuantityOf<quantity<si::radian>, isq::angular_measure>);
 static_assert(!QuantityOf<quantity<si::radian>, dimensionless>);
-static_assert(QuantityOf<quantity<si::radian>, dimension_one>);
 static_assert(QuantityOf<quantity<isq::angular_measure[si::radian]>, isq::angular_measure>);
 static_assert(!QuantityOf<quantity<isq::angular_measure[si::radian]>, dimensionless>);
-static_assert(QuantityOf<quantity<isq::angular_measure[si::radian]>, dimension_one>);
 static_assert(QuantityOf<quantity<one>, isq::rotation>);
 static_assert(QuantityOf<quantity<one>, isq::angular_measure>);
 static_assert(!QuantityOf<quantity<dimensionless[one]>, isq::rotation>);