From 4ef4d0659d1131c297103ac0a0f62cc17ab64b14 Mon Sep 17 00:00:00 2001
From: Charles Milette <me@charlesmilette.net>
Date: Wed, 24 Jul 2019 13:30:43 -0400
Subject: [PATCH] Improve correctness of convertion checks

---
 include/spdlog/logger.h | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/include/spdlog/logger.h b/include/spdlog/logger.h
index 69e3721f..b9300bb8 100644
--- a/include/spdlog/logger.h
+++ b/include/spdlog/logger.h
@@ -143,7 +143,7 @@ public:
     }
 
     // T can be statically converted to string_view
-    template<class T, typename std::enable_if<std::is_convertible<T, spdlog::string_view_t>::value, T>::type * = nullptr>
+    template<class T, typename std::enable_if<std::is_convertible<const T &, spdlog::string_view_t>::value, T>::type * = nullptr>
     void log(source_loc loc, level::level_enum lvl, const T &msg)
     {
         if (!should_log(lvl))
@@ -156,7 +156,7 @@ public:
     }
 
     // T cannot be statically converted to string_view
-    template<class T, typename std::enable_if<!std::is_convertible<T, spdlog::string_view_t>::value, T>::type * = nullptr>
+    template<class T, typename std::enable_if<!std::is_convertible<const T &, spdlog::string_view_t>::value, T>::type * = nullptr>
     void log(source_loc loc, level::level_enum lvl, const T &msg)
     {
         if (!should_log(lvl))
@@ -279,7 +279,7 @@ public:
     }
 
     // T can be statically converted to wstring_view
-    template<class T, typename std::enable_if<std::is_convertible<T, spdlog::wstring_view_t>::value, T>::type * = nullptr>
+    template<class T, typename std::enable_if<std::is_convertible<const T &, spdlog::wstring_view_t>::value, T>::type * = nullptr>
     void log(source_loc loc, level::level_enum lvl, const T &msg)
     {
         if (!should_log(lvl))