From a2376b9b53fe358f50e72138a48d38dc5b6bdf62 Mon Sep 17 00:00:00 2001
From: Mateusz Pusz <mateusz.pusz@gmail.com>
Date: Fri, 25 Aug 2023 21:15:00 +0200
Subject: [PATCH] refactor: workaround to enable clang-16 compilation

---
 src/core/include/mp-units/bits/quantity_concepts.h       | 4 ++++
 src/core/include/mp-units/bits/quantity_point_concepts.h | 4 ++++
 src/core/include/mp-units/quantity.h                     | 8 ++++++++
 src/core/include/mp-units/quantity_point.h               | 8 ++++++++
 4 files changed, 24 insertions(+)

diff --git a/src/core/include/mp-units/bits/quantity_concepts.h b/src/core/include/mp-units/bits/quantity_concepts.h
index 559bfc11..42e5903a 100644
--- a/src/core/include/mp-units/bits/quantity_concepts.h
+++ b/src/core/include/mp-units/bits/quantity_concepts.h
@@ -32,8 +32,12 @@ namespace mp_units {
 template<Reference auto R, RepresentationOf<get_quantity_spec(R).character> Rep>
 class quantity;
 
+#if MP_UNITS_COMP_CLANG < 17
+template<auto R, typename Rep>
+#else
 template<Reference auto R, typename Rep>
   requires quantity<R, std::remove_cvref_t<Rep>>::_rep_safe_constructible_
+#endif
 [[nodiscard]] constexpr quantity<R, std::remove_cvref_t<Rep>> make_quantity(Rep&& v);
 
 namespace detail {
diff --git a/src/core/include/mp-units/bits/quantity_point_concepts.h b/src/core/include/mp-units/bits/quantity_point_concepts.h
index 5aa1257d..695d9da3 100644
--- a/src/core/include/mp-units/bits/quantity_point_concepts.h
+++ b/src/core/include/mp-units/bits/quantity_point_concepts.h
@@ -110,8 +110,12 @@ template<Reference auto R, PointOriginFor<get_quantity_spec(R)> auto PO,
          RepresentationOf<get_quantity_spec(R).character> Rep>
 class quantity_point;
 
+#if MP_UNITS_COMP_CLANG < 17
+template<auto PO, typename Q>
+#else
 template<PointOrigin auto PO, Quantity Q>
   requires ReferenceOf<std::remove_const_t<decltype(Q::reference)>, PO.quantity_spec>
+#endif
 [[nodiscard]] constexpr quantity_point<Q::reference, PO, typename Q::rep> make_quantity_point(Q&& q);
 
 namespace detail {
diff --git a/src/core/include/mp-units/quantity.h b/src/core/include/mp-units/quantity.h
index 0512f733..6cd9a78e 100644
--- a/src/core/include/mp-units/quantity.h
+++ b/src/core/include/mp-units/quantity.h
@@ -325,8 +325,12 @@ public:
   }
 
 private:
+#if MP_UNITS_COMP_CLANG < 17
+  template<auto R2, typename Rep2>
+#else
   template<Reference auto R2, typename Rep2>
     requires quantity<R2, std::remove_cvref_t<Rep2>>::_rep_safe_constructible_
+#endif
   friend constexpr quantity<R2, std::remove_cvref_t<Rep2>> make_quantity(Rep2&&);
 
   template<typename Value>
@@ -435,8 +439,12 @@ template<auto R1, typename Rep1, auto R2, typename Rep2>
 }
 
 // make_quantity
+#if MP_UNITS_COMP_CLANG < 17
+template<auto R, typename Rep>
+#else
 template<Reference auto R, typename Rep>
   requires quantity<R, std::remove_cvref_t<Rep>>::_rep_safe_constructible_
+#endif
 [[nodiscard]] constexpr quantity<R, std::remove_cvref_t<Rep>> make_quantity(Rep&& v)
 {
   return quantity<R, std::remove_cvref_t<Rep>>(std::forward<Rep>(v));
diff --git a/src/core/include/mp-units/quantity_point.h b/src/core/include/mp-units/quantity_point.h
index 23dfaebc..6deea3e0 100644
--- a/src/core/include/mp-units/quantity_point.h
+++ b/src/core/include/mp-units/quantity_point.h
@@ -207,8 +207,12 @@ public:
   }
 
 private:
+#if MP_UNITS_COMP_CLANG < 17
+  template<auto PO2, typename Q>
+#else
   template<PointOrigin auto PO2, Quantity Q>
     requires ReferenceOf<std::remove_const_t<decltype(Q::reference)>, PO2.quantity_spec>
+#endif
   friend constexpr quantity_point<Q::reference, PO2, typename Q::rep> make_quantity_point(Q&&);
 
   template<Quantity Q>
@@ -356,8 +360,12 @@ template<QuantityPoint QP1, QuantityPointOf<QP1::absolute_point_origin> QP2>
 }
 
 // make_quantity_point
+#if MP_UNITS_COMP_CLANG < 17
+template<auto PO, typename Q>
+#else
 template<PointOrigin auto PO, Quantity Q>
   requires ReferenceOf<std::remove_const_t<decltype(Q::reference)>, PO.quantity_spec>
+#endif
 [[nodiscard]] constexpr quantity_point<Q::reference, PO, typename Q::rep> make_quantity_point(Q&& q)
 {
   return quantity_point<Q::reference, PO, typename Q::rep>(std::forward<Q>(q));