From 19a201920498e169399762b0d6ec20b23e991f09 Mon Sep 17 00:00:00 2001
From: Mateusz Pusz <mateusz.pusz@gmail.com>
Date: Fri, 29 Nov 2024 21:20:37 +0100
Subject: [PATCH] feat: proper constraints for `kind_of`

---
 src/core/include/mp-units/framework/quantity_spec.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/core/include/mp-units/framework/quantity_spec.h b/src/core/include/mp-units/framework/quantity_spec.h
index c4497681..e7f1b7c2 100644
--- a/src/core/include/mp-units/framework/quantity_spec.h
+++ b/src/core/include/mp-units/framework/quantity_spec.h
@@ -499,7 +499,7 @@ template<QuantitySpec Q>
 
 }  // namespace detail
 
-template<typename Q>
+template<QuantitySpec Q>
   requires(!detail::QuantityKindSpec<Q>) && (detail::get_kind_tree_root(Q{}) == Q{})
 #if MP_UNITS_API_NO_CRTP
 struct kind_of_<Q> final : Q::_base_type_ {
@@ -510,7 +510,7 @@ struct kind_of_<Q> final : quantity_spec<kind_of_<Q>, Q{}>::_base_type_ {
   static constexpr auto _quantity_spec_ = Q{};
 };
 
-MP_UNITS_EXPORT template<auto Q>
+MP_UNITS_EXPORT template<QuantitySpec auto Q>
   requires requires { typename kind_of_<decltype(Q)>; }
 constexpr kind_of_<MP_UNITS_REMOVE_CONST(decltype(Q))> kind_of;