From 3c24052cf17e23a285316ac52178935599ad6a47 Mon Sep 17 00:00:00 2001
From: Victor Zverovich <viz@fb.com>
Date: Wed, 11 Mar 2020 17:29:07 -0700
Subject: [PATCH] Workaround 'cannot call member function without object' error
 on gcc 4.9

---
 include/fmt/core.h | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/include/fmt/core.h b/include/fmt/core.h
index 72bbddad..8bcc0d06 100644
--- a/include/fmt/core.h
+++ b/include/fmt/core.h
@@ -950,8 +950,9 @@ template <typename Context> struct arg_mapper {
             FMT_ENABLE_IF(std::is_enum<T>::value &&
                           !has_formatter<T, Context>::value &&
                           !has_fallback_formatter<T, Context>::value)>
-  FMT_CONSTEXPR auto map(const T& val) -> decltype(
-      map(static_cast<typename std::underlying_type<T>::type>(val))) {
+  FMT_CONSTEXPR auto map(const T& val)
+      -> decltype(std::declval<arg_mapper>().map(
+          static_cast<typename std::underlying_type<T>::type>(val))) {
     return map(static_cast<typename std::underlying_type<T>::type>(val));
   }
   template <typename T,