From 95e71b10b02e2d5cfe41b5d9f8dd6a01382cf981 Mon Sep 17 00:00:00 2001
From: attila <attila@juce.com>
Date: Wed, 10 Jul 2024 19:25:36 +0200
Subject: [PATCH] FixedSizeFunction: Replace std::aligned_storage_t to avoid
 C++23 warning

We are ignoring warning 4324, which warns us that a FixedSizeFunction<4>
will have it's size increased to 8 bytes, due to the minimum alignment
requirement of 8 bytes.
---
 modules/juce_core/containers/juce_FixedSizeFunction.h | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/modules/juce_core/containers/juce_FixedSizeFunction.h b/modules/juce_core/containers/juce_FixedSizeFunction.h
index 1eedf720df..2d185ee9e5 100644
--- a/modules/juce_core/containers/juce_FixedSizeFunction.h
+++ b/modules/juce_core/containers/juce_FixedSizeFunction.h
@@ -108,14 +108,12 @@ template <size_t len, typename Ret, typename... Args>
 class FixedSizeFunction<len, Ret (Args...)>
 {
 private:
-    using Storage = std::aligned_storage_t<len>;
-
     template <typename Item>
     using Decay = std::decay_t<Item>;
 
     template <typename Item, typename Fn = Decay<Item>>
     using IntIfValidConversion = std::enable_if_t<sizeof (Fn) <= len
-                                                      && alignof (Fn) <= alignof (Storage)
+                                                      && alignof (Fn) <= alignof (std::max_align_t)
                                                       && ! std::is_same_v<FixedSizeFunction, Fn>,
                                                   int>;
 
@@ -137,7 +135,7 @@ public:
     {
         static_assert (sizeof (Fn) <= len,
                        "The requested function cannot fit in this FixedSizeFunction");
-        static_assert (alignof (Fn) <= alignof (Storage),
+        static_assert (alignof (Fn) <= alignof (std::max_align_t),
                        "FixedSizeFunction cannot accommodate the requested alignment requirements");
 
         static constexpr auto vtableForCallable = detail::makeVtable<Fn, Ret, Args...>();
@@ -228,7 +226,10 @@ private:
     }
 
     const detail::Vtable<Ret, Args...>* vtable = nullptr;
-    mutable Storage storage;
+
+    JUCE_BEGIN_IGNORE_WARNINGS_MSVC (4324)
+    alignas (std::max_align_t) mutable std::byte storage[len];
+    JUCE_END_IGNORE_WARNINGS_MSVC
 };
 
 template <size_t len, typename T>