From 471dfa4f604d2506076d5b38b787e7a3c979e57c Mon Sep 17 00:00:00 2001
From: Egor Seredin <egor.seredin@quoine.com>
Date: Thu, 29 Aug 2019 18:14:18 +0900
Subject: [PATCH 1/2] Map not int enum to correct underlying_type

---
 include/fmt/core.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/include/fmt/core.h b/include/fmt/core.h
index 2dc6ed552bbb..cb7f6185fb81 100644
--- a/include/fmt/core.h
+++ b/include/fmt/core.h
@@ -824,8 +824,8 @@ 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 int map(const T& val) {
-    return static_cast<int>(val);
+  FMT_CONSTEXPR auto map(const T& val) -> decltype(map(static_cast<typename std::underlying_type<T>::type>(val))) {
+    return map(static_cast<typename std::underlying_type<T>::type>(val));
   }
   template <typename T,
             FMT_ENABLE_IF(!is_string<T>::value && !is_char<T>::value &&

From 93d1d1507d61d4d3fe0585ec148126c88b7b1efb Mon Sep 17 00:00:00 2001
From: Egor Seredin <egor.seredin@quoine.com>
Date: Thu, 29 Aug 2019 20:01:50 +0900
Subject: [PATCH 2/2] Use non-zero constant in TestFixedEnum

---
 test/format-test.cc | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/test/format-test.cc b/test/format-test.cc
index ffa0a9b276fc..3d619e50932a 100644
--- a/test/format-test.cc
+++ b/test/format-test.cc
@@ -1906,9 +1906,9 @@ TEST(FormatTest, FormatterNotSpecialized) {
 }
 
 #if FMT_HAS_FEATURE(cxx_strong_enums)
-enum TestFixedEnum : short { B };
+enum TestFixedEnum : short { B = 1 };
 
-TEST(FormatTest, FixedEnum) { EXPECT_EQ("0", fmt::format("{}", B)); }
+TEST(FormatTest, FixedEnum) { EXPECT_EQ("1", fmt::format("{}", B)); }
 #endif
 
 using buffer_range = fmt::buffer_range<char>;