From 7893d85394ea1cda51bc772eb5f7fc1b487f5b30 Mon Sep 17 00:00:00 2001
From: Victor Zverovich <victor.zverovich@gmail.com>
Date: Tue, 4 Jun 2019 08:47:25 -0700
Subject: [PATCH] Clarify why we cannot have nice things

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

diff --git a/include/fmt/core.h b/include/fmt/core.h
index c7c74e22..780bb138 100644
--- a/include/fmt/core.h
+++ b/include/fmt/core.h
@@ -1381,6 +1381,8 @@ struct is_contiguous_back_insert_iterator<std::back_insert_iterator<Container>>
     : is_contiguous<Container> {};
 
 /** Formats a string and writes the output to ``out``. */
+// GCC 8 and earlier cannot handle std::back_insert_iterator<Container> with
+// vformat_to<ArgFormatter>(...) overload, so SFINAE on iterator type instead.
 template <typename OutputIt, typename S, typename Char = char_t<S>,
           FMT_ENABLE_IF(is_contiguous_back_insert_iterator<OutputIt>::value)>
 OutputIt vformat_to(OutputIt out, const S& format_str,