From cedfe6e154d1e581cb4d97fe445eb229ce2758ed Mon Sep 17 00:00:00 2001
From: Matthew Gilbert <matthew_gilbert@apple.com>
Date: Thu, 20 May 2021 20:02:33 -0400
Subject: [PATCH] Add missing Allocator template argument for
 basic_memory_buffer in format_to

Remove deduced default template arguments in format_to and vformat_to.
Moves SFINAE check to non-deduced template parameter in format_to.
---
 include/fmt/format.h | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/include/fmt/format.h b/include/fmt/format.h
index bbaef4b00c0d2..053c9bd804607 100644
--- a/include/fmt/format.h
+++ b/include/fmt/format.h
@@ -2691,7 +2691,7 @@ FMT_INLINE auto make_args_checked(const S& fmt,
   return {args...};
 }
 
-template <typename S, typename Char = char_t<S>,
+template <typename S, typename Char,
           FMT_ENABLE_IF(detail::is_string<S>::value)>
 inline void vformat_to(
     detail::buffer<Char>& buf, const S& format_str,
@@ -2699,9 +2699,10 @@ inline void vformat_to(
   return detail::vformat_to(buf, to_string_view(format_str), args);
 }
 
-template <typename S, typename... Args, size_t SIZE = inline_buffer_size,
-          typename Char = enable_if_t<detail::is_string<S>::value, char_t<S>>>
-inline auto format_to(basic_memory_buffer<Char, SIZE>& buf, const S& format_str,
+template <typename S, typename... Args, typename Char, size_t SIZE,
+          typename Allocator, FMT_ENABLE_IF(detail::is_string<S>::value)>
+inline auto format_to(basic_memory_buffer<Char, SIZE, Allocator>& buf,
+                      const S& format_str,
                       Args&&... args) ->
     typename buffer_context<Char>::iterator {
   const auto& vargs = fmt::make_args_checked<Args...>(format_str, args...);