From d8e1c9f175a363e7cfe8ff340df2f77d682bc344 Mon Sep 17 00:00:00 2001
From: Alexey Ochapov <alexez@alexez.com>
Date: Tue, 23 Feb 2021 18:18:30 +0300
Subject: [PATCH] fix `fmt::get` for some GCC versions and legacy Clang (#2144)

fixes https://github.com/fmtlib/fmt/issues/2140

- some GCC versions decay function pointers to `const void*`, exactly like
  MSVC does
- legacy Clang (prior to 7.0) treats function pointers also as `const T*`
  pointers, but unable to convert them
---
 include/fmt/format.h | 17 ++++++-----------
 1 file changed, 6 insertions(+), 11 deletions(-)

diff --git a/include/fmt/format.h b/include/fmt/format.h
index 53094c1a..6d5c1f69 100644
--- a/include/fmt/format.h
+++ b/include/fmt/format.h
@@ -3833,21 +3833,16 @@ FMT_CONSTEXPR void advance_to(
     auto s = fmt::format("{}", fmt::ptr(p));
   \endrst
  */
-template <typename T> inline const void* ptr(const T* p) { return p; }
-template <typename T> inline const void* ptr(const std::unique_ptr<T>& p) {
+template <typename T> const void* ptr(T p) {
+  static_assert(std::is_pointer<T>::value, "");
+  return detail::bit_cast<const void*>(p);
+}
+template <typename T> const void* ptr(const std::unique_ptr<T>& p) {
   return p.get();
 }
-template <typename T> inline const void* ptr(const std::shared_ptr<T>& p) {
+template <typename T> const void* ptr(const std::shared_ptr<T>& p) {
   return p.get();
 }
-#if !FMT_MSC_VER
-// MSVC lets function pointers decay to void pointers, so this
-// overload is unnecessary.
-template <typename T, typename... Args>
-inline const void* ptr(T (*fn)(Args...)) {
-  return detail::bit_cast<const void*>(fn);
-}
-#endif
 
 class bytes {
  private: