Ignore preferreduilang

Author: jjonescz

src/Cli/dotnet/Commands/Run/CSharpCompilerCommand.Generated.cs

@@ -21,7 +21,6 @@ private IEnumerable<string> GetCscArguments(
             "/errorreport:prompt",
             "/warn:10",
             "/define:TRACE;DEBUG;NET;NET10_0;NETCOREAPP;NET5_0_OR_GREATER;NET6_0_OR_GREATER;NET7_0_OR_GREATER;NET8_0_OR_GREATER;NET9_0_OR_GREATER;NET10_0_OR_GREATER;NETCOREAPP1_0_OR_GREATER;NETCOREAPP1_1_OR_GREATER;NETCOREAPP2_0_OR_GREATER;NETCOREAPP2_1_OR_GREATER;NETCOREAPP2_2_OR_GREATER;NETCOREAPP3_0_OR_GREATER;NETCOREAPP3_1_OR_GREATER",
-            "/preferreduilang:en-US",
             "/highentropyva+",
             "/nullable:enable",
             $"/reference:{DotNetRootPath}/packs/Microsoft.NETCore.App.Ref/{RuntimeVersion}/ref/net10.0/Microsoft.CSharp.dll",

test/dotnet.Tests/CommandTests/Run/RunFileTests.cs

@@ -1375,13 +1375,19 @@ private IEnumerable<string> GetCscArguments(
             }
 
             // We don't need to generate a ref assembly.
-            if (arg.StartsWith("/refout", StringComparison.Ordinal))
+            if (arg.StartsWith("/refout:", StringComparison.Ordinal))
             {
                 continue;
             }
 
             // Ignore source link.
-            if (arg.StartsWith("/sourcelink", StringComparison.Ordinal))
+            if (arg.StartsWith("/sourcelink:", StringComparison.Ordinal))
+            {
+                continue;
+            }
+
+            // PreferredUILang is normally not set by default but can be in builds, so ignore it.
+            if (arg.StartsWith("/preferreduilang:", StringComparison.Ordinal))
             {
                 continue;
             }