Add Enum static extensions (#79546)

Author: tmat

src/Analyzers/Core/Analyzers/RemoveUnnecessarySuppressions/SuppressMessageAttributeState.cs

@@ -26,9 +26,7 @@ private static ImmutableDictionary<string, TargetScope> CreateTargetScopesMap()
     {
         var builder = ImmutableDictionary.CreateBuilder<string, TargetScope>(StringComparer.OrdinalIgnoreCase);
 
-#pragma warning disable CS8605 // Unboxing a possibly null value.
-        foreach (TargetScope targetScope in Enum.GetValues(typeof(TargetScope)))
-#pragma warning restore CS8605 // Unboxing a possibly null value.
+        foreach (var targetScope in Enum.GetValues<TargetScope>())
         {
             if (targetScope == TargetScope.None)
             {

src/CodeStyle/Tools/Program.cs

@@ -66,12 +66,12 @@ private static void CreateGlobalConfigFiles(string language, string outputDir, I
         }
 
         var configDir = Path.Combine(outputDir, "config");
-        foreach (var analysisMode in Enum.GetValues(typeof(AnalysisMode)))
+        foreach (var analysisMode in Enum.GetValues<AnalysisMode>())
         {
             CreateGlobalconfig(
                 configDir,
                 $"AnalysisLevelStyle_{analysisMode}.globalconfig".ToLowerInvariant(),
-                (AnalysisMode)analysisMode!,
+                analysisMode,
                 allRulesById);
         }
 

src/Dependencies/Contracts/EnumExtensions.cs

@@ -0,0 +1,27 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+#nullable enable
+
+namespace System;
+
+internal static partial class RoslynEnumExtensions
+{
+#if NET // binary compatibility
+    public static TEnum[] GetValues<TEnum>() where TEnum : struct, Enum
+        => Enum.GetValues<TEnum>();
+
+    public static string[] GetNames<TEnum>() where TEnum : struct, Enum
+        => Enum.GetNames<TEnum>();
+#else
+    extension(Enum)
+    {
+        public static TEnum[] GetValues<TEnum>() where TEnum : struct, Enum
+            => (TEnum[])Enum.GetValues(typeof(TEnum));
+
+        public static string[] GetNames<TEnum>() where TEnum : struct, Enum
+            => Enum.GetNames(typeof(TEnum));
+    }
+#endif
+}

src/EditorFeatures/CSharpTest/Completion/CompletionProviders/ExtensionMethodImportCompletionProviderTests.cs

@@ -40,7 +40,7 @@ public enum ReferenceType
 
     private static IEnumerable<object[]> CombineWithReferenceTypeData(IEnumerable<List<object>> data)
     {
-        foreach (var refKind in Enum.GetValues(typeof(ReferenceType)))
+        foreach (var refKind in Enum.GetValues<ReferenceType>())
         {
             foreach (var d in data)
             {

src/EditorFeatures/CSharpTest/LanguageServer/CSharpLspBuildOnlyDiagnosticsTests.cs

@@ -21,7 +21,7 @@ protected override ImmutableArray<string> ExpectedDiagnosticCodes
     {
         get
         {
-            var errorCodes = Enum.GetValues(typeof(ErrorCode));
+            var errorCodes = Enum.GetValues<ErrorCode>();
             var supported = new CSharpCompilerDiagnosticAnalyzer().GetSupportedErrorCodes();
             var builder = ImmutableArray.CreateBuilder<string>();
             foreach (int errorCode in errorCodes)

src/EditorFeatures/Core/Logging/FunctionIdOptions.cs

@@ -35,7 +35,7 @@ private static Option2<bool> CreateOption(FunctionId id)
     }
 
     private static IEnumerable<FunctionId> GetFunctionIds()
-        => Enum.GetValues(typeof(FunctionId)).Cast<FunctionId>();
+        => Enum.GetValues<FunctionId>();
 
     public static IEnumerable<IOption2> GetOptions()
         => GetFunctionIds().Select(GetOption);

src/EditorFeatures/Test/EditorConfigSettings/Data/CodeStyleSettingsTest.cs

@@ -66,8 +66,8 @@ public static void CodeStyleSettingEnumFactory(DayOfWeek defaultValue)
             description: "TestDesciption",
             options,
             updater: null!,
-            enumValues: (DayOfWeek[])Enum.GetValues(typeof(DayOfWeek)),
-            valueDescriptions: Enum.GetNames(typeof(DayOfWeek)));
+            enumValues: Enum.GetValues<DayOfWeek>(),
+            valueDescriptions: Enum.GetNames<DayOfWeek>());
 
         Assert.Equal(string.Empty, setting.Category);
         Assert.Equal("TestDesciption", setting.Description);

src/ExpressionEvaluator/CSharp/Test/ResultProvider/ResultProviderTests.cs

@@ -15,7 +15,7 @@ public class ResultProviderTests
         [Fact]
         public void DkmEvaluationFlagsConflict()
         {
-            var values = Enum.GetValues(typeof(DkmEvaluationFlags)).Cast<DkmEvaluationFlags>().ToArray();
+            var values = Enum.GetValues<DkmEvaluationFlags>();
             Assert.False(values.Contains(ResultProvider.NoResults));
             Assert.False(values.Contains(ResultProvider.NotRoot));
         }

src/Features/CSharpTest/Diagnostics/Suppression/RemoveUnnecessaryPragmaSuppressionsTests.cs

@@ -136,7 +136,7 @@ protected override ImmutableArray<string> UnsupportedDiagnosticIds
             {
                 get
                 {
-                    var errorCodes = Enum.GetValues(typeof(ErrorCode));
+                    var errorCodes = Enum.GetValues<ErrorCode>();
                     var supported = ((CSharpCompilerDiagnosticAnalyzer)OtherAnalyzers[0]).GetSupportedErrorCodes();
                     using var _ = ArrayBuilder<string>.GetInstance(out var builder);
                     foreach (int errorCode in errorCodes)

src/Features/CSharpTest/EditAndContinue/CSharpEditAndContinueAnalyzerTests.cs

@@ -87,7 +87,7 @@ private static IEnumerable<TextSpan> GetExpectedSpans(string source)
     private static void TestErrorSpansAllKinds(Func<SyntaxKind, bool> hasLabel)
     {
         var unhandledKinds = new List<SyntaxKind>();
-        foreach (var kind in Enum.GetValues(typeof(SyntaxKind)).Cast<SyntaxKind>().Where(hasLabel))
+        foreach (var kind in Enum.GetValues<SyntaxKind>().Where(hasLabel))
         {
             TextSpan? span;
             try