refactor: 💥 ReferenceOf does not take a dimension anymore

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

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