From 75c3e26a53c18f7aab591c6a80f271ca9bc38f4c Mon Sep 17 00:00:00 2001
From: Mateusz Pusz <mateusz.pusz@gmail.com>
Date: Mon, 13 Feb 2023 18:18:08 +0100
Subject: [PATCH] fix: `has_associated_quantity` fixed

---
 src/core/include/mp_units/bits/unit_concepts.h | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/src/core/include/mp_units/bits/unit_concepts.h b/src/core/include/mp_units/bits/unit_concepts.h
index 165582e7..11f4f505 100644
--- a/src/core/include/mp_units/bits/unit_concepts.h
+++ b/src/core/include/mp_units/bits/unit_concepts.h
@@ -140,12 +140,14 @@ template<typename... Us>
 template<Unit U>
 [[nodiscard]] consteval bool has_associated_quantity(U)
 {
+  if constexpr (requires { U::quantity_spec; })
+      return true;
   if constexpr (requires { U::reference_unit; })
     return has_associated_quantity(U::reference_unit);
   else if constexpr (requires { typename U::_num_; })
     return has_associated_quantity(typename U::_num_{}) && has_associated_quantity(typename U::_den_{});
   else
-    return requires { U::base_quantity; };
+    return false;
 }
 
 }  // namespace detail