From c03288b0a7ee49b4753c8e45b090df916d9b75a6 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Daniel=20Kr=C3=BCgler?= <daniel.kruegler@gmail.com>
Date: Sun, 10 Jul 2022 09:16:17 +0200
Subject: [PATCH] - Rename is_not_recursive_range to is_nonrecursive_range and
 add comment that explains it being depending on is_range being true - Merge
 has_fallback_formatter_delayed into is_formattable_delayed and add comment
 that explains it being depending on is_not_recursive_range being true -
 Replace disjunction in formatter specialization by
 has_fallback_formatter_delayed - Get rid of unneeded detail:: prefixes within
 namespace detail

---
 include/fmt/ranges.h | 29 ++++++++++++++---------------
 1 file changed, 14 insertions(+), 15 deletions(-)

diff --git a/include/fmt/ranges.h b/include/fmt/ranges.h
index 280d1c57..8b7c9aad 100644
--- a/include/fmt/ranges.h
+++ b/include/fmt/ranges.h
@@ -391,19 +391,21 @@ template <typename R>
 using maybe_const_range =
     conditional_t<has_const_begin_end<R>::value, const R, R>;
 
+// is_nonrecursive_range depends on fmt::is_range<T, Char>::value == true.
+// It exists to ensure short-circuit evaluation in the constraint of the 
+// formatter specialization below. A similar approach is used in 
+// https://wg21.link/p2286.
 template <typename R>
-struct is_not_recursive_range : bool_constant<
-    !std::is_same<detail::uncvref_type<R>, R>::value> {};
+struct is_nonrecursive_range : bool_constant<
+    !std::is_same<uncvref_type<R>, R>::value> {};
 
+// is_formattable_delayed depends on is_nonrecursive_range<R>::value == true.
+// It exists to ensure short-circuit evaluation in the constraint of the 
+// formatter specialization below.
 template <typename R, typename Char>
-struct is_formattable_delayed : is_formattable<
-    detail::uncvref_type<detail::maybe_const_range<R>>, Char> {
-};
-
-template <typename R, typename Char>
-struct has_fallback_formatter_delayed : detail::has_fallback_formatter<
-    detail::uncvref_type<detail::maybe_const_range<R>>, Char> {
-};
+struct is_formattable_delayed : disjunction<
+    is_formattable<uncvref_type<maybe_const_range<R>>, Char>,
+    has_fallback_formatter<uncvref_type<maybe_const_range<R>>, Char>> {};
 
 }  // namespace detail
 
@@ -412,14 +414,11 @@ struct formatter<
     R, Char,
     enable_if_t<
         conjunction<fmt::is_range<R, Char>,
-          detail::is_not_recursive_range<R>
+          detail::is_nonrecursive_range<R>
 // Workaround a bug in MSVC 2015 and earlier.
 #if !FMT_MSC_VERSION || FMT_MSC_VERSION > 1900
           ,
-          disjunction<
-              detail::is_formattable_delayed<R, Char>,
-              detail::has_fallback_formatter_delayed<R, Char>
-          >
+          detail::is_formattable_delayed<R, Char>
 #endif
         >::value
         >> {