A concept matching all quantity specifications in the library
Declared in <mp-units/framework/quantity_spec_concepts.h>
template<typename T>
concept QuantitySpec = std::derived_from<T, detail::quantity_spec_interface_base> && detail::SymbolicConstant<T> &&
!detail::is_specialization_of_quantity_spec<T>;Satisfied by strong types derived from a quantity_spec specialization, excluding quantity_spec specializations themselves.