From 5d755d0a4e50076f78bebc4869f10d27f45b5db5 Mon Sep 17 00:00:00 2001
From: Victor Zverovich <victor.zverovich@gmail.com>
Date: Sun, 14 Apr 2019 12:34:56 -0700
Subject: [PATCH] Fix handling of volatile char (#1115)

---
 include/fmt/core.h  | 11 ++++++-----
 test/format-test.cc |  5 +++++
 2 files changed, 11 insertions(+), 5 deletions(-)

diff --git a/include/fmt/core.h b/include/fmt/core.h
index cc55c0e8..8dc68e40 100644
--- a/include/fmt/core.h
+++ b/include/fmt/core.h
@@ -872,11 +872,12 @@ inline init<C, basic_string_view<Char>, string_type> make_value(const T& val) {
 // unsafe: https://github.com/fmtlib/fmt/issues/729
 template <
     typename C, typename T, typename Char = typename C::char_type,
-    FMT_ENABLE_IF(!convert_to_int<T, Char>::value &&
-                  !std::is_same<T, Char>::value &&
-                  !std::is_convertible<T, basic_string_view<Char>>::value &&
-                  !is_constructible<basic_string_view<Char>, T>::value &&
-                  !internal::is_string<T>::value)>
+    typename U = typename std::remove_volatile<T>::type,
+    FMT_ENABLE_IF(!convert_to_int<U, Char>::value &&
+                  !std::is_same<U, Char>::value &&
+                  !std::is_convertible<U, basic_string_view<Char>>::value &&
+                  !is_constructible<basic_string_view<Char>, U>::value &&
+                  !internal::is_string<U>::value)>
 inline init<C, const T&, custom_type> make_value(const T& val) {
   return val;
 }
diff --git a/test/format-test.cc b/test/format-test.cc
index 1aa2e43e..34550bc2 100644
--- a/test/format-test.cc
+++ b/test/format-test.cc
@@ -1550,6 +1550,11 @@ TEST(FormatterTest, FormatChar) {
   EXPECT_EQ(fmt::format("{:02X}", n), fmt::format("{:02X}", 'x'));
 }
 
+TEST(FormatterTest, FormatVolatileChar) {
+  volatile char c = 'x';
+  EXPECT_EQ("x", format("{}", c));
+}
+
 TEST(FormatterTest, FormatUnsignedChar) {
   EXPECT_EQ("42", format("{}", static_cast<unsigned char>(42)));
   EXPECT_EQ("42", format("{}", static_cast<uint8_t>(42)));