From 3d39e3e50d778ec3564b5fe2025569e6d0d94a24 Mon Sep 17 00:00:00 2001
From: Sam <30577766+Samasaur1@users.noreply.github.com>
Date: Wed, 15 Oct 2025 22:44:10 -0700
Subject: [PATCH] ghc_filesystem: disable new Clang 21 warning

This warning was added in Clang 21, causing this package to break on
Darwin as well as any other LLVM stdenv. Upstream hasn't changed and
hasn't released a version in two and a half years, so I'm just disabling
the warning.

(I did check whether updating to the latest `master` fixes the issue,
and it does not).
---
 pkgs/by-name/gh/ghc_filesystem/package.nix | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/pkgs/by-name/gh/ghc_filesystem/package.nix b/pkgs/by-name/gh/ghc_filesystem/package.nix
index 3119d6af64cf..503de44f004c 100644
--- a/pkgs/by-name/gh/ghc_filesystem/package.nix
+++ b/pkgs/by-name/gh/ghc_filesystem/package.nix
@@ -19,6 +19,9 @@ stdenv.mkDerivation (finalAttrs: {
 
   nativeBuildInputs = [ cmake ];
 
+  # https://github.com/NixOS/nixpkgs/issues/451580
+  env.NIX_CFLAGS_COMPILE = lib.optionalString stdenv.cc.isClang "-Wno-error=character-conversion";
+
   passthru = {
     updateScript = nix-update-script { };
   };