[clang] [clang] Add release note for int->enum conversion change. (PR #144407)

[Eli Friedman via cfe-commits]

https://github.com/efriedma-quic created https://github.com/llvm/llvm-project/pull/144407

This seems to be having some practical impact, so we should let people know.

>From 72b5793a6b0df71ec78e691aaa1b0729273263e0 Mon Sep 17 00:00:00 2001
From: Eli Friedman <efriedma at quicinc.com>
Date: Mon, 16 Jun 2025 11:04:04 -0700
Subject: [PATCH] [clang] Add release note for int->enum conversion change.

This seems to be having some practical impact, so we should let people
know.
---
 clang/docs/ReleaseNotes.rst | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index b42d5f8425af6..e9455c0756bd9 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -65,8 +65,10 @@ C++ Specific Potentially Breaking Changes
   standard library already have their own bespoke builtins.
 - A workaround for libstdc++4.7 has been removed. Note that 4.8.3 remains the oldest
   supported libstdc++ version.
-
 - Added ``!nonnull/!align`` metadata to load of references for better codegen.
+- Checking for int->enum conversions in constant expressions is more strict;
+  in particular, ``const E x = (E)-1;`` is not treated as a constant if it's
+  out of range. This impacts old versions of Boost.  (#GH143034)
 
 ABI Changes in This Version
 ---------------------------