diff --git a/src/include/units/quantity_cast.h b/src/include/units/quantity_cast.h
index 06b8a1ca..b3195e37 100644
--- a/src/include/units/quantity_cast.h
+++ b/src/include/units/quantity_cast.h
@@ -287,10 +287,10 @@ template<Dimension ToD, Unit ToU, typename D, typename U, typename Rep>
  */
 template<typename CastSpec, typename K, typename U, typename Rep>
 [[nodiscard]] constexpr QuantityKind auto quantity_kind_cast(const quantity_kind<K, U, Rep>& qk)
-  requires (is_specialization_of<CastSpec, quantity_kind> &&
-              requires { quantity_cast<typename CastSpec::quantity_type>(qk.common()); }) ||
-           (Kind<CastSpec> && UnitOf<U, typename CastSpec::dimension>) ||
-           requires { quantity_cast<CastSpec>(qk.common()); }
+  requires requires { requires is_specialization_of<CastSpec, quantity_kind>;
+              requires requires { quantity_cast<typename CastSpec::quantity_type>(qk.common()); }; } ||
+           requires { requires Kind<CastSpec>; requires UnitOf<U, typename CastSpec::dimension>; } ||
+           requires { requires requires { quantity_cast<CastSpec>(qk.common()); }; }
 {
   if constexpr (is_specialization_of<CastSpec, quantity_kind>)
     return CastSpec(quantity_cast<typename CastSpec::quantity_type>(qk.common()));
diff --git a/src/include/units/quantity_kind.h b/src/include/units/quantity_kind.h
index 2e40d978..874a0552 100644
--- a/src/include/units/quantity_kind.h
+++ b/src/include/units/quantity_kind.h
@@ -241,21 +241,21 @@ public:
   // Below friend functions are to be found via argument-dependent lookup only
   template<QuantityValue Value>
   [[nodiscard]] friend constexpr QuantityKind auto operator*(const quantity_kind& qk, const Value& v)
-    requires requires { { qk.common() * v } -> Quantity; }
+    requires requires(quantity_type q) { { q * v } -> Quantity; }
   {
     return detail::make_quantity_kind<quantity_kind>(qk.common() * v);
   }
 
   template<QuantityValue Value>
   [[nodiscard]] friend constexpr QuantityKind auto operator*(const Value& v, const quantity_kind& qk)
-    requires requires { { v * qk.common() } -> Quantity; }
+    requires requires(quantity_type q) { { v * q } -> Quantity; }
   {
     return detail::make_quantity_kind<quantity_kind>(v * qk.common());
   }
 
   template<QuantityValue Value>
   [[nodiscard]] friend constexpr QuantityKind auto operator/(const quantity_kind& qk, const Value& v)
-    requires requires { { qk.common() / v } -> Quantity; }
+    requires requires(quantity_type q) { { q / v } -> Quantity; }
   {
     gsl_ExpectsAudit(v != quantity_values<Value>::zero());
     return detail::make_quantity_kind<quantity_kind>(qk.common() / v);
@@ -263,7 +263,7 @@ public:
 
   template<QuantityValue Value>
   [[nodiscard]] friend constexpr QuantityKind auto operator/(const Value& v, const quantity_kind& qk)
-    requires requires { { v / qk.common() } -> Quantity; }
+    requires requires(quantity_type q) { { v / q } -> Quantity; }
   {
     gsl_ExpectsAudit(qk.common().count() != quantity_values<rep>::zero());
     return detail::downcasted_kind<quantity_kind>(v / qk.common());
@@ -271,7 +271,7 @@ public:
 
   template<QuantityValue Value>
   [[nodiscard]] friend constexpr QuantityKind auto operator%(const quantity_kind& qk, const Value& v)
-    requires requires { qk.common() % v; }
+    requires requires(quantity_type q) { q % v; }
   {
     gsl_ExpectsAudit(v != quantity_values<Value>::zero());
     return detail::make_quantity_kind<quantity_kind>(qk.common() % v);