From 8cb0961fba2ca742510f120f6d85909050e615ec Mon Sep 17 00:00:00 2001
From: Felix <felix-antoine.constantin@polymtl.ca>
Date: Wed, 2 Aug 2023 21:43:52 -0400
Subject: [PATCH] Added format_as for std::vector<bool>::reference

---
 include/fmt/std.h | 9 +++++++++
 test/std-test.cc  | 5 +++++
 2 files changed, 14 insertions(+)

diff --git a/include/fmt/std.h b/include/fmt/std.h
index a71a59db..62e091ce 100644
--- a/include/fmt/std.h
+++ b/include/fmt/std.h
@@ -15,6 +15,7 @@
 #include <type_traits>
 #include <typeinfo>
 #include <utility>
+#include <vector>
 
 #include "format.h"
 #include "ostream.h"
@@ -391,4 +392,12 @@ struct formatter<
 };
 FMT_END_NAMESPACE
 
+namespace std
+{
+template <typename T, FMT_ENABLE_IF(std::is_same<T, std::vector<bool>::reference>::value)>
+inline auto format_as(T b) -> bool {
+  return static_cast<bool>(b);
+}
+}
+
 #endif  // FMT_STD_H_
diff --git a/test/std-test.cc b/test/std-test.cc
index fda8e96b..643d93c6 100644
--- a/test/std-test.cc
+++ b/test/std-test.cc
@@ -221,3 +221,8 @@ TEST(std_test, exception) {
   }
 #endif
 }
+
+TEST(std_test, format_vector_bool_specialization) {
+  std::vector<bool> v = {true, false};
+  EXPECT_EQ(fmt::format("{} {}", v[0], v[1]), "true false");
+}