From b723c021dfd521ca528925ae20472bac81089faa Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Tobias=20Schl=C3=BCter?=
 <TobiSchluter@users.noreply.github.com>
Date: Wed, 21 May 2025 04:21:06 +0900
Subject: [PATCH] Give useful error when misusing fmt::ptr. (#4453)

static_assert(bla, "") prints an empty message but not the condition with at least MSVC. Add an informative message.
---
 include/fmt/format.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/fmt/format.h b/include/fmt/format.h
index c559b45f..5aac87e4 100644
--- a/include/fmt/format.h
+++ b/include/fmt/format.h
@@ -3824,7 +3824,7 @@ struct formatter<T, Char, void_t<detail::format_as_result<T>>>
  *     auto s = fmt::format("{}", fmt::ptr(p));
  */
 template <typename T> auto ptr(T p) -> const void* {
-  static_assert(std::is_pointer<T>::value, "");
+  static_assert(std::is_pointer<T>::value, "fmt::ptr used with non-pointer");
   return detail::bit_cast<const void*>(p);
 }