diff --git a/test_package/test_package.cpp b/test_package/test_package.cpp
index 72a27f88..0ab5bdb0 100644
--- a/test_package/test_package.cpp
+++ b/test_package/test_package.cpp
@@ -28,7 +28,7 @@
 
 using namespace mp_units;
 
-constexpr QuantityOf<isq::speed> auto avg_speed(QuantityOf<isq::distance> auto d, QuantityOf<isq::duration> auto t)
+constexpr QuantityOf<isq::speed> auto avg_speed(QuantityOf<(isq::distance)> auto d, QuantityOf<(isq::duration)> auto t)
 {
   return d / t;
 }