diff --git a/src/core/include/mp-units/bits/reference_concepts.h b/src/core/include/mp-units/bits/reference_concepts.h index 61cd917d..c51d2d59 100644 --- a/src/core/include/mp-units/bits/reference_concepts.h +++ b/src/core/include/mp-units/bits/reference_concepts.h @@ -74,6 +74,9 @@ template concept ReferenceOf = Reference && ((Dimension> && get_quantity_spec(T{}).dimension == V) || - (QuantitySpec> && implicitly_convertible(get_quantity_spec(T{}), V))); + (QuantitySpec> && implicitly_convertible(get_quantity_spec(T{}), V) && + !detail::DerivedFromQuantityKindSpecOf && + (detail::QuantityKindSpec> || + !detail::DerivedFromQuantityKindSpecOf))); } // namespace mp_units