From 3168b15a9b2b0a961fdff2f89129c679aa3d94f1 Mon Sep 17 00:00:00 2001
From: Chaitanya Kumar <chaitanya@passivelogic.com>
Date: Fri, 26 Sep 2025 21:35:00 +0200
Subject: [PATCH 1/2] fix: remove preceding `-Xcc` instead of the argument
 following `-Werror` or `-Wwarning`

https://github.com/swiftlang/swift-package-manager/issues/9192
---
 .../Build/BuildDescription/SwiftModuleBuildDescription.swift  | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/Sources/Build/BuildDescription/SwiftModuleBuildDescription.swift b/Sources/Build/BuildDescription/SwiftModuleBuildDescription.swift
index b6b6c20fffa..6e7e2283158 100644
--- a/Sources/Build/BuildDescription/SwiftModuleBuildDescription.swift
+++ b/Sources/Build/BuildDescription/SwiftModuleBuildDescription.swift
@@ -612,7 +612,7 @@ public final class SwiftModuleBuildDescription {
         if self.package.isRemote {
             // suppress-warnings and the other warning control flags are mutually exclusive
             var removeNextArg = false
-            args = args.filter { arg in
+            args = Array(args.lazy.reversed().filter { arg in
                 if removeNextArg {
                     removeNextArg = false
                     return false
@@ -626,7 +626,7 @@ public final class SwiftModuleBuildDescription {
                 default:
                     return true
                 }
-            }
+            }.reversed())
             guard !removeNextArg else {
                 throw InternalError("Unexpected '-Wwarning' or '-Werror' at the end of args")
             }

From 91f258748af95167eb3cf351d842d0419309ffcc Mon Sep 17 00:00:00 2001
From: Chaitanya Kumar <chaitanya@passivelogic.com>
Date: Mon, 29 Sep 2025 22:46:33 +0200
Subject: [PATCH 2/2] refactor: use simple for loop instead of filter with
 side-effect closure

---
 .../SwiftModuleBuildDescription.swift         | 23 ++++++++-----------
 1 file changed, 9 insertions(+), 14 deletions(-)

diff --git a/Sources/Build/BuildDescription/SwiftModuleBuildDescription.swift b/Sources/Build/BuildDescription/SwiftModuleBuildDescription.swift
index 6e7e2283158..8e227186daf 100644
--- a/Sources/Build/BuildDescription/SwiftModuleBuildDescription.swift
+++ b/Sources/Build/BuildDescription/SwiftModuleBuildDescription.swift
@@ -611,26 +611,21 @@ public final class SwiftModuleBuildDescription {
         // suppress warnings if the package is remote
         if self.package.isRemote {
             // suppress-warnings and the other warning control flags are mutually exclusive
-            var removeNextArg = false
-            args = Array(args.lazy.reversed().filter { arg in
-                if removeNextArg {
-                    removeNextArg = false
-                    return false
-                }
+            var filteredArgs = [String]()
+            for arg in args {
                 switch arg {
                 case "-warnings-as-errors", "-no-warnings-as-errors":
-                    return false
+                    // Skip this flag
+                    continue
                 case "-Wwarning", "-Werror":
-                    removeNextArg = true
-                    return false
+                    // Remove preceding -Xcc and skip this flag
+                    filteredArgs.removeLast()
                 default:
-                    return true
+                    filteredArgs.append(arg)
                 }
-            }.reversed())
-            guard !removeNextArg else {
-                throw InternalError("Unexpected '-Wwarning' or '-Werror' at the end of args")
             }
-            args += ["-suppress-warnings"]
+            args = filteredArgs
+            args.append("-suppress-warnings")
         }
 
         // Pass `-user-module-version` for versioned packages that aren't pre-releases.