From eb96c466f5ebe69530fbc89cb0a28a547e38a4eb Mon Sep 17 00:00:00 2001
From: Barry Revzin <barry.revzin@gmail.com>
Date: Tue, 18 Aug 2020 11:23:29 -0500
Subject: [PATCH] Adding message to static_assert

---
 test/format-test.cc | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/test/format-test.cc b/test/format-test.cc
index f7a1a9bd..c79aa548 100644
--- a/test/format-test.cc
+++ b/test/format-test.cc
@@ -2485,9 +2485,9 @@ template <> struct formatter<check_back_appender> {
 
   template <typename Context>
   auto format(check_back_appender, Context& ctx) -> decltype(ctx.out()) {
-    // needs to satisfy weakly_incrementable
     auto out = ctx.out();
-    static_assert(std::is_same<decltype(++out), decltype(out)&>::value);
+    static_assert(std::is_same<decltype(++out), decltype(out)&>::value,
+                  "needs to satisfy weakly_incrementable");
     *out = 'y';
     return ++out;
   }
@@ -2497,4 +2497,3 @@ FMT_END_NAMESPACE
 TEST(FormatTest, BackInsertSlicing) {
   EXPECT_EQ(fmt::format("{}", check_back_appender{}), "y");
 }
-