From 87d442772c553d818b250345107dce20ce085508 Mon Sep 17 00:00:00 2001
From: Danny Robson <danny@nerdcruft.net>
Date: Mon, 16 Apr 2018 15:58:13 +1000
Subject: [PATCH] geom/ops: remove point-point distance via sfinae

point-point distance is already defined outside of the geom namespace
---
 geom/ops.hpp | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/geom/ops.hpp b/geom/ops.hpp
index 304edc20..1cf82c85 100644
--- a/geom/ops.hpp
+++ b/geom/ops.hpp
@@ -11,7 +11,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  *
- * Copyright 2015 Danny Robson <danny@nerdcruft.net>
+ * Copyright 2015-2018 Danny Robson <danny@nerdcruft.net>
  */
 
 #ifndef __UTIL_GEOM_OPS_HPP
@@ -20,6 +20,8 @@
 #include "./fwd.hpp"
 #include "../point.hpp"
 
+#include <type_traits>
+
 
 ///////////////////////////////////////////////////////////////////////////////
 namespace util::geom {
@@ -41,11 +43,17 @@ namespace util::geom {
     T
     distance2 (A<S,T>, B<S,T>);
 
+    // disable distance for point-point arguments given it's already
+    // explicitly specified in the point header.
     template <
         size_t S,
         typename T,
         template <size_t,typename> class A,
-        template <size_t,typename> class B
+        template <size_t,typename> class B,
+        typename = std::enable_if_t<
+            !std::is_same_v<util::point<S,T>, A> &&
+            !std::is_same_v<util::point<S,T>, B>
+        >
     >
     T
     distance (A<S,T>, B<S,T>);