From 330d160824659c43f811fc0bd486fed4440404ac Mon Sep 17 00:00:00 2001
From: Alex Overchenko <aleksandr9809@gmail.com>
Date: Sat, 31 Aug 2024 19:42:05 +0300
Subject: [PATCH] Disable "warnings as errors" flag for CL preprocessing
 (#2251)

---
 src/compiler/msvc.rs             | 3 ++-
 tests/msvc-preprocessing/foo.cpp | 8 ++++++++
 2 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/src/compiler/msvc.rs b/src/compiler/msvc.rs
index ccf77ce75..b9b797888 100644
--- a/src/compiler/msvc.rs
+++ b/src/compiler/msvc.rs
@@ -908,7 +908,8 @@ pub fn preprocess_cmd<T>(
         }
         // Windows SDK generates C4668 during preprocessing, but compiles fine.
         // Read for more info: https://github.com/mozilla/sccache/issues/1725
-        cmd.arg("/wd4668");
+        // And here: https://github.com/mozilla/sccache/issues/2250
+        cmd.arg("/WX-");
     }
 
     if rewrite_includes_only && is_clang {
diff --git a/tests/msvc-preprocessing/foo.cpp b/tests/msvc-preprocessing/foo.cpp
index e0604526f..511b0a75d 100644
--- a/tests/msvc-preprocessing/foo.cpp
+++ b/tests/msvc-preprocessing/foo.cpp
@@ -10,6 +10,14 @@ __pragma(warning(disable: 4668))
 #endif
 __pragma(warning(pop))
 
+// Minimal reproducible example for errors from user code
+// More information: https://github.com/mozilla/sccache/issues/2250
+#pragma warning(disable : 4002)
+
+#define F(x, y)
+
 int main() {
+  F(2, , , , , , 3, , , , , , ) // C4002
+
   return 0;
 }