diff --git a/geom/ops.hpp b/geom/ops.hpp
index ee21a308..7f1eed6d 100644
--- a/geom/ops.hpp
+++ b/geom/ops.hpp
@@ -55,12 +55,12 @@ namespace cruft::geom {
         size_t S,
         typename T,
         template <size_t,typename> class A,
-        template <size_t,typename> class B,
-        typename = std::enable_if_t<
-            !std::is_same_v<cruft::point<S,T>, A<S,T>> &&
-            !std::is_same_v<cruft::point<S,T>, B<S,T>>
-        >
+        template <size_t,typename> class B
     >
+    requires (
+        !std::is_same_v<cruft::point<S,T>, A<S,T>> &&
+        !std::is_same_v<cruft::point<S,T>, B<S,T>>
+    )
     T
     distance (A<S,T>, B<S,T>);