From fe11777d7873ab2c73fcaf91536cdb9edfafea20 Mon Sep 17 00:00:00 2001
From: Alexey Ochapov <alexez@alexez.com>
Date: Wed, 4 Nov 2020 01:04:12 +0300
Subject: [PATCH] actual fix to eliminate warnings

---
 include/fmt/format.h | 29 ++++++++++++++++++-----------
 1 file changed, 18 insertions(+), 11 deletions(-)

diff --git a/include/fmt/format.h b/include/fmt/format.h
index ea45429f..87c62fed 100644
--- a/include/fmt/format.h
+++ b/include/fmt/format.h
@@ -3198,17 +3198,24 @@ FMT_CONSTEXPR basic_string_view<Char> compile_string_to_view(
   return {s.data(), s.size()};
 }
 
-#define FMT_STRING_IMPL(s, base)                                  \
-  [] {                                                            \
-    /* Use a macro-like name to avoid shadowing warnings. */      \
-    struct FMT_COMPILE_STRING : base {                            \
-      using char_type = fmt::remove_cvref_t<decltype(s[0])>;      \
-      FMT_MAYBE_UNUSED FMT_CONSTEXPR                              \
-      operator fmt::basic_string_view<char_type>() const {        \
-        return fmt::detail::compile_string_to_view<char_type>(s); \
-      }                                                           \
-    };                                                            \
-    return FMT_COMPILE_STRING();                                  \
+#if defined(FMT_GCC_VERSION) && FMT_GCC_VERSION >= 400
+#  define FMT_COMPILE_STRING_VISIBILITY_ATTRIBUTE \
+    __attribute__((visibility("hidden")))
+#else
+#  define FMT_COMPILE_STRING_VISIBILITY_ATTRIBUTE
+#endif
+
+#define FMT_STRING_IMPL(s, base)                                               \
+  [] {                                                                         \
+    /* Use a macro-like name to avoid shadowing warnings. */                   \
+    struct FMT_COMPILE_STRING_VISIBILITY_ATTRIBUTE FMT_COMPILE_STRING : base { \
+      using char_type = fmt::remove_cvref_t<decltype(s[0])>;                   \
+      FMT_MAYBE_UNUSED FMT_CONSTEXPR                                           \
+      operator fmt::basic_string_view<char_type>() const {                     \
+        return fmt::detail::compile_string_to_view<char_type>(s);              \
+      }                                                                        \
+    };                                                                         \
+    return FMT_COMPILE_STRING();                                               \
   }()
 
 /**