From 6c1062e166238b560c78e789122e1badd3c5971e Mon Sep 17 00:00:00 2001
From: Mateusz Pusz <mateusz.pusz@gmail.com>
Date: Sat, 14 May 2022 11:22:09 +0200
Subject: [PATCH] fix: `UNITS_MSVC_WORKAROUND()` added

---
 src/core/include/units/bits/common_type.h    |  6 +++---
 src/core/include/units/bits/external/hacks.h | 10 ++++++++++
 src/core/include/units/derived_dimension.h   |  2 +-
 src/core/include/units/prefix.h              |  2 +-
 src/core/include/units/unit.h                |  2 +-
 5 files changed, 16 insertions(+), 6 deletions(-)

diff --git a/src/core/include/units/bits/common_type.h b/src/core/include/units/bits/common_type.h
index 40880927..46f7cb5f 100644
--- a/src/core/include/units/bits/common_type.h
+++ b/src/core/include/units/bits/common_type.h
@@ -67,9 +67,9 @@ struct common_quantity_reference_impl<reference<D1, U1>, reference<D2, U2>> {
 template<typename D1, typename U1, typename D2, typename U2>
 struct common_quantity_reference_impl<reference<D1, U1>, reference<D2, U2>> {
   using dimension = conditional<is_specialization_of<D1, unknown_dimension>, D2, D1>;
-  static constexpr Magnitude auto m1 = D1::base_units_ratio * U1::mag;
-  static constexpr Magnitude auto m2 = D2::base_units_ratio * U2::mag;
-  static constexpr Magnitude auto cm = common_magnitude(m1, m2);
+  static constexpr UNITS_MSVC_WORKAROUND(Magnitude) auto m1 = D1::base_units_ratio * U1::mag;
+  static constexpr UNITS_MSVC_WORKAROUND(Magnitude) auto m2 = D2::base_units_ratio * U2::mag;
+  static constexpr UNITS_MSVC_WORKAROUND(Magnitude) auto cm = common_magnitude(m1, m2);
   using unit = downcast_unit<dimension, cm / dimension::base_units_ratio>;
   using type = reference<dimension, unit>;
 };
diff --git a/src/core/include/units/bits/external/hacks.h b/src/core/include/units/bits/external/hacks.h
index 5a983540..169718ba 100644
--- a/src/core/include/units/bits/external/hacks.h
+++ b/src/core/include/units/bits/external/hacks.h
@@ -100,6 +100,16 @@
 
 #endif
 
+#if UNITS_COMP_MSVC
+
+#define UNITS_MSVC_WORKAROUND(X)
+
+#else
+
+#define UNITS_MSVC_WORKAROUND(X) (X)
+
+#endif
+
 
 namespace std {
 
diff --git a/src/core/include/units/derived_dimension.h b/src/core/include/units/derived_dimension.h
index 76c8dc9f..cfe0830c 100644
--- a/src/core/include/units/derived_dimension.h
+++ b/src/core/include/units/derived_dimension.h
@@ -85,7 +85,7 @@ template<typename Child, Unit U, Exponent... Es>
 struct derived_dimension : downcast_dispatch<Child, typename detail::make_dimension<Es...>> {
   using recipe = exponent_list<Es...>;
   using coherent_unit = U;
-  static constexpr Magnitude auto base_units_ratio =
+  static constexpr UNITS_MSVC_WORKAROUND(Magnitude) auto base_units_ratio =
     detail::absolute_magnitude(typename derived_dimension::exponents());
 };
 
diff --git a/src/core/include/units/prefix.h b/src/core/include/units/prefix.h
index e460b4de..0a95499c 100644
--- a/src/core/include/units/prefix.h
+++ b/src/core/include/units/prefix.h
@@ -36,7 +36,7 @@ namespace detail {
 
 template<ratio R>
 struct prefix_base : downcast_base<prefix_base<R>> {
-  static constexpr Magnitude auto mag = as_magnitude<R>();
+  static constexpr UNITS_MSVC_WORKAROUND(Magnitude) auto mag = as_magnitude<R>();
 };
 
 }  // namespace detail
diff --git a/src/core/include/units/unit.h b/src/core/include/units/unit.h
index c429f837..3e4f7253 100644
--- a/src/core/include/units/unit.h
+++ b/src/core/include/units/unit.h
@@ -60,7 +60,7 @@ inline constexpr bool can_be_prefixed = false;
  */
 template<Magnitude auto M, typename U>
 struct scaled_unit : downcast_base<scaled_unit<M, U>> {
-  static constexpr Magnitude auto mag = M;
+  static constexpr UNITS_MSVC_WORKAROUND(Magnitude) auto mag = M;
   using reference = U;
 };