Add WarningsAsErrors and WarningsNotAsErrors

src/ILLink.Tasks/LinkTask.cs

@@ -67,6 +67,25 @@ public class ILLink : ToolTask
 		/// </summary>
 		public string Warn { get; set; }
 
+		/// <summary>
+		/// Treat all warnings as errors.
+		/// Maps to '--warnaserror' if true, '--warnaserror-' if false.
+		/// </summary>
+		public bool TreatWarningsAsErrors { set => _treatWarningsAsErrors = value; }
+		bool? _treatWarningsAsErrors;
+
+		/// <summary>
+		/// The list of warnings to report as errors.
+		/// Maps to '--warnaserror LIST-OF-WARNINGS'.
+		/// </summary>
+		public string WarningsAsErrors { get; set; }
+
+		/// <summary>
+		/// The list of warnings to report as usual.
+		/// Maps to '--warnaserror- LIST-OF-WARNINGS'.
+		/// </summary>
+		public string WarningsNotAsErrors { get; set; }
+
 		/// <summary>
 		///   A list of XML root descriptor files specifying linker
 		///   roots at a granular level. See the mono/linker
@@ -315,6 +334,17 @@ protected override string GenerateResponseFileCommands ()
 			if (Warn != null)
 				args.Append ("--warn ").AppendLine (Quote (Warn));
 
+			if (_treatWarningsAsErrors is bool treatWarningsAsErrors && treatWarningsAsErrors)
+				args.Append ("--warnaserror ");
+			else
+				args.Append ("--warnaserror- ");
+
+			if (WarningsAsErrors != null)
+				args.Append ("--warnaserror ").AppendLine (Quote (WarningsAsErrors));
+
+			if (WarningsNotAsErrors != null)
+				args.Append ("--warnaserror- ").AppendLine (Quote (WarningsNotAsErrors));
+
 			// Add global optimization arguments
 			if (_beforeFieldInit is bool beforeFieldInit)
 				SetOpt (args, "beforefieldinit", beforeFieldInit);

src/linker/Linker/Driver.cs

@@ -777,18 +777,18 @@ string Unquote (string arg)
 
 			value = Unquote (value);
 			string[] values = value.Split (new char[] { ',', ';', ' ' }, StringSplitOptions.RemoveEmptyEntries);
-			HashSet<uint> noWarnCodes = new HashSet<uint> ();
+			HashSet<uint> warningCodes = new HashSet<uint> ();
 			foreach (string id in values) {
 				if (!id.StartsWith ("IL", StringComparison.Ordinal))
 					continue;
 
 				var warningCode = id.Substring (2);
 				if (ushort.TryParse (warningCode, out ushort code)
 					&& code > 2000 && code <= 6000)
-					noWarnCodes.Add (code);
+					warningCodes.Add (code);
 			}
 
-			return noWarnCodes;
+			return warningCodes;
 		}
 
 		private static Assembly GetCustomAssembly (string arg)

test/ILLink.Tasks.Tests/ILLink.Tasks.Tests.cs

@@ -4,13 +4,9 @@
 using System.Linq;
 using System.Reflection;
 using Xunit;
-using Xunit.Abstractions;
-using Xunit.Sdk;
 using Microsoft.Build.Framework;
 using Microsoft.Build.Utilities;
-using ILLink.Tasks;
 using Mono.Linker;
-using Mono.Linker.Steps;
 
 namespace ILLink.Tasks.Tests
 {
@@ -306,6 +302,43 @@ public void TestWarn (string warnArg, WarnVersion expectedVersion)
 			}
 		}
 
+#nullable enable
+		[Theory]
+		[InlineData (true, null, null, new uint[] { }, new uint[] { })]
+		[InlineData (false, "IL1001,IL####,IL2000,IL2021,IL2022", null,
+			new uint[] { 2021, 2022 }, new uint[] { })]
+		[InlineData (false, "IL2023,IL6000;IL5042 IL2040", "IL4000,IL4001;IL4002 IL4003",
+			new uint[] { 2023, 2040, 5042, 6000 }, new uint[] { 4000, 4001, 4002, 4003 })]
+		[InlineData (false, "IL3000;IL3000;ABCD", "IL2005 il3000 IL2005",
+			new uint[] { 3000 }, new uint[] { 2005 })]
+		[InlineData (true, null, "IL2006", new uint[] { }, new uint[] { 2006 })]
+		[InlineData (true, "IL2001", "IL2001", new uint[] { }, new uint[] { 2001 })]
+		public void TestWarningsAsErrors (bool treatWarningsAsErrors, string? warningsAsErrors, string? warningsNotAsErrors, uint[] warnAsError, uint[] warnNotAsError)
+		{
+			var task = new MockTask () {
+				TreatWarningsAsErrors = treatWarningsAsErrors,
+				WarningsAsErrors = warningsAsErrors,
+				WarningsNotAsErrors = warningsNotAsErrors
+			};
+
+			using (var driver = task.CreateDriver ()) {
+				var actualWarnAsError = driver.Context.WarnAsError;
+				var actualGeneralWarnAsError = driver.Context.GeneralWarnAsError;
+				Assert.Equal (actualWarnAsError.Count, warnAsError.Distinct ().Count () + warnNotAsError.Distinct ().Count ());
+				Assert.Equal (actualGeneralWarnAsError, treatWarningsAsErrors);
+				if (warnAsError.Length > 0) {
+					foreach (var warningCode in warnAsError)
+						Assert.True (actualWarnAsError.ContainsKey (warningCode) && actualWarnAsError[warningCode] == true);
+				}
+
+				if (warnNotAsError.Length > 0) {
+					foreach (var warningCode in warnNotAsError)
+						Assert.True (actualWarnAsError.ContainsKey (warningCode) && actualWarnAsError[warningCode] == false);
+				}
+			}
+		}
+#nullable disable
+
 		public static IEnumerable<object[]> CustomDataCases => new List<object[]> {
 			new object [] {
 				new ITaskItem [] {

test/ILLink.Tasks.Tests/Mock.cs

@@ -45,7 +45,8 @@ public void SetOptimization (string optimization, bool enabled)
 
 		static readonly string[] nonOptimizationBooleanProperties = new string[] {
 			"DumpDependencies",
-			"RemoveSymbols"
+			"RemoveSymbols",
+			"TreatWarningsAsErrors"
 		};
 
 		public static IEnumerable<string> GetOptimizationPropertyNames ()