From 055684bc415f93bb43a3faecbfcc199d7f952f79 Mon Sep 17 00:00:00 2001
From: Pranam Lashkari <plashkari628@gmail.com>
Date: Sat, 5 Sep 2020 22:16:28 +0530
Subject: [PATCH] resolve c2146 on vs15 with area_result declaration

---
 include/boost/geometry/algorithms/area_result.hpp | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/include/boost/geometry/algorithms/area_result.hpp b/include/boost/geometry/algorithms/area_result.hpp
index c5d43cdc1..beb63136a 100644
--- a/include/boost/geometry/algorithms/area_result.hpp
+++ b/include/boost/geometry/algorithms/area_result.hpp
@@ -46,9 +46,10 @@ template
     bool IsUmbrella = strategies::detail::is_umbrella_strategy<Strategy>::value
 >
 struct area_result
-    : decltype(std::declval<Strategy>().area(std::declval<Geometry>()))
-        ::template result_type<Geometry>
-{};
+{
+    typedef decltype(std::declval<Strategy>().area(std::declval<Geometry>())) strategy_type;
+    typedef typename strategy_type::template result_type<Geometry>::type type;
+};
 
 template
 <