From 7a79a15f4f41ce8bdd30bae711a1d75fcc136a5c Mon Sep 17 00:00:00 2001
From: Mateusz Pusz <mateusz.pusz@gmail.com>
Date: Thu, 16 May 2024 18:33:10 +0200
Subject: [PATCH] fix: `derived_quantity_spec` definition fixed for C++23

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

diff --git a/src/core/include/mp-units/quantity_spec.h b/src/core/include/mp-units/quantity_spec.h
index 5f70d034..c5741a74 100644
--- a/src/core/include/mp-units/quantity_spec.h
+++ b/src/core/include/mp-units/quantity_spec.h
@@ -424,7 +424,11 @@ struct quantity_spec<Self, QS, Eq, Args...> : quantity_spec<Self, QS, Args...> {
  */
 template<detail::IntermediateDerivedQuantitySpecExpr... Expr>
 struct derived_quantity_spec :
+#ifdef __cpp_explicit_this_parameter
+    detail::quantity_spec_interface,
+#else
     detail::quantity_spec_interface<derived_quantity_spec<Expr...>>,
+#endif
     detail::expr_fractions<detail::is_dimensionless, Expr...> {
   using _base_ = detail::expr_fractions<detail::is_dimensionless, Expr...>;