dotnet · CyrusNajmabadi · Mar 27, 2025 · Mar 26, 2025 · Mar 26, 2025 · Mar 26, 2025
diff --git a/...lyzers/AddRequiredParentheses/CSharpAddRequiredExpressionParenthesesDiagnosticAnalyzer.cs b/...lyzers/AddRequiredParentheses/CSharpAddRequiredExpressionParenthesesDiagnosticAnalyzer.cs
@@ -13,7 +13,7 @@
 namespace Microsoft.CodeAnalysis.CSharp.AddRequiredParentheses;
 
 [DiagnosticAnalyzer(LanguageNames.CSharp)]
-internal class CSharpAddRequiredExpressionParenthesesDiagnosticAnalyzer :
+internal sealed class CSharpAddRequiredExpressionParenthesesDiagnosticAnalyzer :
     AbstractAddRequiredParenthesesDiagnosticAnalyzer<
         ExpressionSyntax, ExpressionSyntax, SyntaxKind>
 {

diff --git a/...Analyzers/AddRequiredParentheses/CSharpAddRequiredPatternParenthesesDiagnosticAnalyzer.cs b/...Analyzers/AddRequiredParentheses/CSharpAddRequiredPatternParenthesesDiagnosticAnalyzer.cs
@@ -13,7 +13,7 @@
 namespace Microsoft.CodeAnalysis.CSharp.AddRequiredParentheses;
 
 [DiagnosticAnalyzer(LanguageNames.CSharp)]
-internal class CSharpAddRequiredPatternParenthesesDiagnosticAnalyzer :
+internal sealed class CSharpAddRequiredPatternParenthesesDiagnosticAnalyzer :
     AbstractAddRequiredParenthesesDiagnosticAnalyzer<
         PatternSyntax, BinaryPatternSyntax, SyntaxKind>
 {

diff --git a/...zers/CSharp/Analyzers/ConvertNamespace/ConvertToBlockScopedNamespaceDiagnosticAnalyzer.cs b/...zers/CSharp/Analyzers/ConvertNamespace/ConvertToBlockScopedNamespaceDiagnosticAnalyzer.cs
@@ -12,7 +12,7 @@
 namespace Microsoft.CodeAnalysis.CSharp.ConvertNamespace;
 
 [DiagnosticAnalyzer(LanguageNames.CSharp)]
-internal class ConvertToBlockScopedNamespaceDiagnosticAnalyzer : AbstractBuiltInCodeStyleDiagnosticAnalyzer
+internal sealed class ConvertToBlockScopedNamespaceDiagnosticAnalyzer : AbstractBuiltInCodeStyleDiagnosticAnalyzer
 {
     public ConvertToBlockScopedNamespaceDiagnosticAnalyzer()
         : base(IDEDiagnosticIds.UseBlockScopedNamespaceDiagnosticId,

diff --git a/...yzers/CSharp/Analyzers/ConvertNamespace/ConvertToFileScopedNamespaceDiagnosticAnalyzer.cs b/...yzers/CSharp/Analyzers/ConvertNamespace/ConvertToFileScopedNamespaceDiagnosticAnalyzer.cs
@@ -12,7 +12,7 @@
 namespace Microsoft.CodeAnalysis.CSharp.ConvertNamespace;
 
 [DiagnosticAnalyzer(LanguageNames.CSharp)]
-internal class ConvertToFileScopedNamespaceDiagnosticAnalyzer : AbstractBuiltInCodeStyleDiagnosticAnalyzer
+internal sealed class ConvertToFileScopedNamespaceDiagnosticAnalyzer : AbstractBuiltInCodeStyleDiagnosticAnalyzer
 {
     public ConvertToFileScopedNamespaceDiagnosticAnalyzer()
         : base(IDEDiagnosticIds.UseFileScopedNamespaceDiagnosticId,

diff --git a/src/Analyzers/CSharp/Analyzers/FileHeaders/CSharpFileHeaderDiagnosticAnalyzer.cs b/src/Analyzers/CSharp/Analyzers/FileHeaders/CSharpFileHeaderDiagnosticAnalyzer.cs
@@ -8,7 +8,7 @@
 namespace Microsoft.CodeAnalysis.CSharp.FileHeaders;
 
 [DiagnosticAnalyzer(LanguageNames.CSharp)]
-internal class CSharpFileHeaderDiagnosticAnalyzer : AbstractFileHeaderDiagnosticAnalyzer
+internal sealed class CSharpFileHeaderDiagnosticAnalyzer : AbstractFileHeaderDiagnosticAnalyzer
 {
     protected override AbstractFileHeaderHelper FileHeaderHelper => CSharpFileHeaderHelper.Instance;
 }
diff --git a/src/Analyzers/CSharp/Analyzers/Formatting/CSharpFormattingAnalyzer.cs b/src/Analyzers/CSharp/Analyzers/Formatting/CSharpFormattingAnalyzer.cs
@@ -9,7 +9,7 @@
 namespace Microsoft.CodeAnalysis.CodeStyle;
 
 [DiagnosticAnalyzer(LanguageNames.CSharp)]
-internal class CSharpFormattingAnalyzer : AbstractFormattingAnalyzer
+internal sealed class CSharpFormattingAnalyzer : AbstractFormattingAnalyzer
 {
     protected override ISyntaxFormatting SyntaxFormatting
         => CSharpSyntaxFormatting.Instance;

diff --git a/...harp/Analyzers/MatchFolderAndNamespace/CSharpMatchFolderAndNamespaceDiagnosticAnalyzer.cs b/...harp/Analyzers/MatchFolderAndNamespace/CSharpMatchFolderAndNamespaceDiagnosticAnalyzer.cs
@@ -20,7 +20,7 @@ namespace Microsoft.CodeAnalysis.CSharp.Analyzers.MatchFolderAndNamespace;
 [Export(typeof(CSharpMatchFolderAndNamespaceDiagnosticAnalyzer)), Shared]
 #endif
 [DiagnosticAnalyzer(LanguageNames.CSharp)]
-internal class CSharpMatchFolderAndNamespaceDiagnosticAnalyzer
+internal sealed class CSharpMatchFolderAndNamespaceDiagnosticAnalyzer
     : AbstractMatchFolderAndNamespaceDiagnosticAnalyzer<SyntaxKind, BaseNamespaceDeclarationSyntax>
 {
 #if !CODE_STYLE

diff --git a/src/Analyzers/CSharp/Analyzers/OrderModifiers/CSharpOrderModifiersDiagnosticAnalyzer.cs b/src/Analyzers/CSharp/Analyzers/OrderModifiers/CSharpOrderModifiersDiagnosticAnalyzer.cs
@@ -13,7 +13,7 @@
 namespace Microsoft.CodeAnalysis.CSharp.OrderModifiers;
 
 [DiagnosticAnalyzer(LanguageNames.CSharp)]
-internal class CSharpOrderModifiersDiagnosticAnalyzer : AbstractOrderModifiersDiagnosticAnalyzer
+internal sealed class CSharpOrderModifiersDiagnosticAnalyzer : AbstractOrderModifiersDiagnosticAnalyzer
 {
     public CSharpOrderModifiersDiagnosticAnalyzer()
         : base(CSharpSyntaxFacts.Instance,

diff --git a/src/Analyzers/CSharp/Analyzers/OrderModifiers/CSharpOrderModifiersHelper.cs b/src/Analyzers/CSharp/Analyzers/OrderModifiers/CSharpOrderModifiersHelper.cs
@@ -8,7 +8,7 @@
 
 namespace Microsoft.CodeAnalysis.CSharp.OrderModifiers;
 
-internal class CSharpOrderModifiersHelper : AbstractOrderModifiersHelpers
+internal sealed class CSharpOrderModifiersHelper : AbstractOrderModifiersHelpers
 {
     public static readonly CSharpOrderModifiersHelper Instance = new();
 

diff --git a/...eUnnecessaryParentheses/CSharpRemoveUnnecessaryExpressionParenthesesDiagnosticAnalyzer.cs b/...eUnnecessaryParentheses/CSharpRemoveUnnecessaryExpressionParenthesesDiagnosticAnalyzer.cs
@@ -15,7 +15,7 @@
 namespace Microsoft.CodeAnalysis.CSharp.RemoveUnnecessaryParentheses;
 
 [DiagnosticAnalyzer(LanguageNames.CSharp)]
-internal class CSharpRemoveUnnecessaryExpressionParenthesesDiagnosticAnalyzer
+internal sealed class CSharpRemoveUnnecessaryExpressionParenthesesDiagnosticAnalyzer
     : AbstractRemoveUnnecessaryParenthesesDiagnosticAnalyzer<SyntaxKind, ParenthesizedExpressionSyntax>
 {
     protected override SyntaxKind GetSyntaxKind()

diff --git a/...moveUnnecessaryParentheses/CSharpRemoveUnnecessaryPatternParenthesesDiagnosticAnalyzer.cs b/...moveUnnecessaryParentheses/CSharpRemoveUnnecessaryPatternParenthesesDiagnosticAnalyzer.cs
@@ -15,7 +15,7 @@
 namespace Microsoft.CodeAnalysis.CSharp.RemoveUnnecessaryParentheses;
 
 [DiagnosticAnalyzer(LanguageNames.CSharp)]
-internal class CSharpRemoveUnnecessaryPatternParenthesesDiagnosticAnalyzer
+internal sealed class CSharpRemoveUnnecessaryPatternParenthesesDiagnosticAnalyzer
     : AbstractRemoveUnnecessaryParenthesesDiagnosticAnalyzer<SyntaxKind, ParenthesizedPatternSyntax>
 {
     protected override SyntaxKind GetSyntaxKind()

diff --git a/...s/CSharp/Analyzers/RemoveUnreachableCode/CSharpRemoveUnreachableCodeDiagnosticAnalyzer.cs b/...s/CSharp/Analyzers/RemoveUnreachableCode/CSharpRemoveUnreachableCodeDiagnosticAnalyzer.cs
@@ -14,7 +14,7 @@
 namespace Microsoft.CodeAnalysis.CSharp.RemoveUnreachableCode;
 
 [DiagnosticAnalyzer(LanguageNames.CSharp)]
-internal class CSharpRemoveUnreachableCodeDiagnosticAnalyzer : AbstractBuiltInUnnecessaryCodeStyleDiagnosticAnalyzer
+internal sealed class CSharpRemoveUnreachableCodeDiagnosticAnalyzer : AbstractBuiltInUnnecessaryCodeStyleDiagnosticAnalyzer
 {
     private const string CS0162 = nameof(CS0162); // Unreachable code detected
 

diff --git a/...CSharp/Analyzers/SimplifyBooleanExpression/CSharpSimplifyConditionalDiagnosticAnalyzer.cs b/...CSharp/Analyzers/SimplifyBooleanExpression/CSharpSimplifyConditionalDiagnosticAnalyzer.cs
@@ -13,7 +13,7 @@
 namespace Microsoft.CodeAnalysis.CSharp.SimplifyBooleanExpression;
 
 [DiagnosticAnalyzer(LanguageNames.CSharp)]
-internal class CSharpSimplifyConditionalDiagnosticAnalyzer :
+internal sealed class CSharpSimplifyConditionalDiagnosticAnalyzer :
     AbstractSimplifyConditionalDiagnosticAnalyzer<
         SyntaxKind,
         ExpressionSyntax,

diff --git a/...harp/Analyzers/SimplifyPropertyPattern/CSharpSimplifyPropertyPatternDiagnosticAnalyzer.cs b/...harp/Analyzers/SimplifyPropertyPattern/CSharpSimplifyPropertyPatternDiagnosticAnalyzer.cs
@@ -20,7 +20,7 @@ namespace Microsoft.CodeAnalysis.CSharp.SimplifyPropertyPattern;
 ///     <c>x is { a.b: ... }</c>
 /// </summary>
 [DiagnosticAnalyzer(LanguageNames.CSharp)]
-internal class CSharpSimplifyPropertyPatternDiagnosticAnalyzer : AbstractBuiltInCodeStyleDiagnosticAnalyzer
+internal sealed class CSharpSimplifyPropertyPatternDiagnosticAnalyzer : AbstractBuiltInCodeStyleDiagnosticAnalyzer
 {
     public CSharpSimplifyPropertyPatternDiagnosticAnalyzer()
         : base(IDEDiagnosticIds.SimplifyPropertyPatternDiagnosticId,

diff --git a/...ession/CSharpUseCoalesceExpressionForNullableTernaryConditionalCheckDiagnosticAnalyzer.cs b/...ession/CSharpUseCoalesceExpressionForNullableTernaryConditionalCheckDiagnosticAnalyzer.cs
@@ -12,7 +12,7 @@
 namespace Microsoft.CodeAnalysis.CSharp.UseCoalesceExpression;
 
 [DiagnosticAnalyzer(LanguageNames.CSharp)]
-internal class CSharpUseCoalesceExpressionForNullableTernaryConditionalCheckDiagnosticAnalyzer :
+internal sealed class CSharpUseCoalesceExpressionForNullableTernaryConditionalCheckDiagnosticAnalyzer :
     AbstractUseCoalesceExpressionForNullableTernaryConditionalCheckDiagnosticAnalyzer<
         SyntaxKind,
         ExpressionSyntax,

diff --git a/...esceExpression/CSharpUseCoalesceExpressionForTernaryConditionalCheckDiagnosticAnalyzer.cs b/...esceExpression/CSharpUseCoalesceExpressionForTernaryConditionalCheckDiagnosticAnalyzer.cs
@@ -12,7 +12,7 @@
 namespace Microsoft.CodeAnalysis.CSharp.UseCoalesceExpression;
 
 [DiagnosticAnalyzer(LanguageNames.CSharp)]
-internal class CSharpUseCoalesceExpressionForTernaryConditionalCheckDiagnosticAnalyzer :
+internal sealed class CSharpUseCoalesceExpressionForTernaryConditionalCheckDiagnosticAnalyzer :
     AbstractUseCoalesceExpressionForTernaryConditionalCheckDiagnosticAnalyzer<
         SyntaxKind,
         ExpressionSyntax,

diff --git a/...ers/UseConditionalExpression/CSharpUseConditionalExpressionForReturnDiagnosticAnalyzer.cs b/...ers/UseConditionalExpression/CSharpUseConditionalExpressionForReturnDiagnosticAnalyzer.cs
@@ -12,7 +12,7 @@
 namespace Microsoft.CodeAnalysis.CSharp.UseConditionalExpression;
 
 [DiagnosticAnalyzer(LanguageNames.CSharp)]
-internal class CSharpUseConditionalExpressionForReturnDiagnosticAnalyzer
+internal sealed class CSharpUseConditionalExpressionForReturnDiagnosticAnalyzer
     : AbstractUseConditionalExpressionForReturnDiagnosticAnalyzer<IfStatementSyntax>
 {
     public CSharpUseConditionalExpressionForReturnDiagnosticAnalyzer()

diff --git a/...Analyzers/CSharp/Analyzers/UseDefaultLiteral/CSharpUseDefaultLiteralDiagnosticAnalyzer.cs b/...Analyzers/CSharp/Analyzers/UseDefaultLiteral/CSharpUseDefaultLiteralDiagnosticAnalyzer.cs
@@ -12,7 +12,7 @@
 namespace Microsoft.CodeAnalysis.CSharp.UseDefaultLiteral;
 
 [DiagnosticAnalyzer(LanguageNames.CSharp)]
-internal class CSharpUseDefaultLiteralDiagnosticAnalyzer : AbstractBuiltInUnnecessaryCodeStyleDiagnosticAnalyzer
+internal sealed class CSharpUseDefaultLiteralDiagnosticAnalyzer : AbstractBuiltInUnnecessaryCodeStyleDiagnosticAnalyzer
 {
     public CSharpUseDefaultLiteralDiagnosticAnalyzer()
         : base(IDEDiagnosticIds.UseDefaultLiteralDiagnosticId,

diff --git a/...zers/CSharp/Analyzers/UseExpressionBody/Helpers/UseExpressionBodyForConstructorsHelper.cs b/...zers/CSharp/Analyzers/UseExpressionBody/Helpers/UseExpressionBodyForConstructorsHelper.cs
@@ -10,7 +10,7 @@
 
 namespace Microsoft.CodeAnalysis.CSharp.UseExpressionBody;
 
-internal class UseExpressionBodyForConstructorsHelper :
+internal sealed class UseExpressionBodyForConstructorsHelper :
     UseExpressionBodyHelper<ConstructorDeclarationSyntax>
 {
     public static readonly UseExpressionBodyForConstructorsHelper Instance = new();

diff --git a/...harp/Analyzers/UseExpressionBody/Helpers/UseExpressionBodyForConversionOperatorsHelper.cs b/...harp/Analyzers/UseExpressionBody/Helpers/UseExpressionBodyForConversionOperatorsHelper.cs
@@ -10,7 +10,7 @@
 
 namespace Microsoft.CodeAnalysis.CSharp.UseExpressionBody;
 
-internal class UseExpressionBodyForConversionOperatorsHelper :
+internal sealed class UseExpressionBodyForConversionOperatorsHelper :
     UseExpressionBodyHelper<ConversionOperatorDeclarationSyntax>
 {
     public static readonly UseExpressionBodyForConversionOperatorsHelper Instance = new();

diff --git a/...ers/CSharp/Analyzers/UseExpressionBody/Helpers/UseExpressionBodyForLocalFunctionHelper.cs b/...ers/CSharp/Analyzers/UseExpressionBody/Helpers/UseExpressionBodyForLocalFunctionHelper.cs
@@ -13,7 +13,7 @@
 
 namespace Microsoft.CodeAnalysis.CSharp.UseExpressionBody;
 
-internal class UseExpressionBodyForLocalFunctionHelper :
+internal sealed class UseExpressionBodyForLocalFunctionHelper :
     UseExpressionBodyHelper<LocalFunctionStatementSyntax>
 {
     public static readonly UseExpressionBodyForLocalFunctionHelper Instance = new();

diff --git a/...Analyzers/CSharp/Analyzers/UseExpressionBody/Helpers/UseExpressionBodyForMethodsHelper.cs b/...Analyzers/CSharp/Analyzers/UseExpressionBody/Helpers/UseExpressionBodyForMethodsHelper.cs
@@ -13,7 +13,7 @@
 
 namespace Microsoft.CodeAnalysis.CSharp.UseExpressionBody;
 
-internal class UseExpressionBodyForMethodsHelper :
+internal sealed class UseExpressionBodyForMethodsHelper :
     UseExpressionBodyHelper<MethodDeclarationSyntax>
 {
     public static readonly UseExpressionBodyForMethodsHelper Instance = new();

diff --git a/...alyzers/CSharp/Analyzers/UseExpressionBody/Helpers/UseExpressionBodyForOperatorsHelper.cs b/...alyzers/CSharp/Analyzers/UseExpressionBody/Helpers/UseExpressionBodyForOperatorsHelper.cs
@@ -12,7 +12,7 @@
 
 namespace Microsoft.CodeAnalysis.CSharp.UseExpressionBody;
 
-internal class UseExpressionBodyForOperatorsHelper :
+internal sealed class UseExpressionBodyForOperatorsHelper :
     UseExpressionBodyHelper<OperatorDeclarationSyntax>
 {
     public static readonly UseExpressionBodyForOperatorsHelper Instance = new();

diff --git a/...lyzers/CSharp/Analyzers/UseExpressionBody/Helpers/UseExpressionBodyForPropertiesHelper.cs b/...lyzers/CSharp/Analyzers/UseExpressionBody/Helpers/UseExpressionBodyForPropertiesHelper.cs
@@ -14,7 +14,7 @@
 
 namespace Microsoft.CodeAnalysis.CSharp.UseExpressionBody;
 
-internal class UseExpressionBodyForPropertiesHelper :
+internal sealed class UseExpressionBodyForPropertiesHelper :
     UseExpressionBodyHelper<PropertyDeclarationSyntax>
 {
     public static readonly UseExpressionBodyForPropertiesHelper Instance = new();

diff --git a/.../Analyzers/UseImplicitObjectCreation/CSharpUseImplicitObjectCreationDiagnosticAnalyzer.cs b/.../Analyzers/UseImplicitObjectCreation/CSharpUseImplicitObjectCreationDiagnosticAnalyzer.cs
@@ -16,7 +16,7 @@
 namespace Microsoft.CodeAnalysis.CSharp.UseImplicitObjectCreation;
 
 [DiagnosticAnalyzer(LanguageNames.CSharp)]
-internal class CSharpUseImplicitObjectCreationDiagnosticAnalyzer : AbstractBuiltInCodeStyleDiagnosticAnalyzer
+internal sealed class CSharpUseImplicitObjectCreationDiagnosticAnalyzer : AbstractBuiltInCodeStyleDiagnosticAnalyzer
 {
     public CSharpUseImplicitObjectCreationDiagnosticAnalyzer()
         : base(IDEDiagnosticIds.UseImplicitObjectCreationDiagnosticId,

diff --git a/...lyzers/UseIsNullCheck/CSharpUseIsNullCheckForCastAndEqualityOperatorDiagnosticAnalyzer.cs b/...lyzers/UseIsNullCheck/CSharpUseIsNullCheckForCastAndEqualityOperatorDiagnosticAnalyzer.cs
@@ -12,7 +12,7 @@
 namespace Microsoft.CodeAnalysis.CSharp.UseIsNullCheck;
 
 [DiagnosticAnalyzer(LanguageNames.CSharp)]
-internal class CSharpUseIsNullCheckForCastAndEqualityOperatorDiagnosticAnalyzer
+internal sealed class CSharpUseIsNullCheckForCastAndEqualityOperatorDiagnosticAnalyzer
     : AbstractBuiltInCodeStyleDiagnosticAnalyzer
 {
     private static readonly ImmutableDictionary<string, string?> s_properties =

diff --git a/...harp/Analyzers/UseIsNullCheck/CSharpUseIsNullCheckForReferenceEqualsDiagnosticAnalyzer.cs b/...harp/Analyzers/UseIsNullCheck/CSharpUseIsNullCheckForReferenceEqualsDiagnosticAnalyzer.cs
@@ -11,7 +11,7 @@
 namespace Microsoft.CodeAnalysis.CSharp.UseIsNullCheck;
 
 [DiagnosticAnalyzer(LanguageNames.CSharp)]
-internal class CSharpUseIsNullCheckForReferenceEqualsDiagnosticAnalyzer : AbstractUseIsNullCheckForReferenceEqualsDiagnosticAnalyzer<SyntaxKind>
+internal sealed class CSharpUseIsNullCheckForReferenceEqualsDiagnosticAnalyzer : AbstractUseIsNullCheckForReferenceEqualsDiagnosticAnalyzer<SyntaxKind>
 {
     public CSharpUseIsNullCheckForReferenceEqualsDiagnosticAnalyzer()
         : base(CSharpAnalyzersResources.Use_is_null_check)

diff --git a/src/Analyzers/CSharp/Analyzers/UseLocalFunction/CSharpUseLocalFunctionDiagnosticAnalyzer.cs b/src/Analyzers/CSharp/Analyzers/UseLocalFunction/CSharpUseLocalFunctionDiagnosticAnalyzer.cs
@@ -39,7 +39,7 @@ namespace Microsoft.CodeAnalysis.CSharp.UseLocalFunction;
 ///     }
 /// </summary>
 [DiagnosticAnalyzer(LanguageNames.CSharp)]
-internal class CSharpUseLocalFunctionDiagnosticAnalyzer : AbstractBuiltInCodeStyleDiagnosticAnalyzer
+internal sealed class CSharpUseLocalFunctionDiagnosticAnalyzer : AbstractBuiltInCodeStyleDiagnosticAnalyzer
 {
     public CSharpUseLocalFunctionDiagnosticAnalyzer()
         : base(IDEDiagnosticIds.UseLocalFunctionDiagnosticId,

diff --git a/src/Analyzers/CSharp/Analyzers/UsePatternMatching/CSharpIsAndCastCheckDiagnosticAnalyzer.cs b/src/Analyzers/CSharp/Analyzers/UsePatternMatching/CSharpIsAndCastCheckDiagnosticAnalyzer.cs
@@ -29,7 +29,7 @@ namespace Microsoft.CodeAnalysis.CSharp.UsePatternMatching;
 ///     }
 /// </summary>
 [DiagnosticAnalyzer(LanguageNames.CSharp)]
-internal class CSharpIsAndCastCheckDiagnosticAnalyzer : AbstractBuiltInCodeStyleDiagnosticAnalyzer
+internal sealed class CSharpIsAndCastCheckDiagnosticAnalyzer : AbstractBuiltInCodeStyleDiagnosticAnalyzer
 {
     public static readonly CSharpIsAndCastCheckDiagnosticAnalyzer Instance = new();
 

diff --git a/...alyzers/CSharp/Analyzers/UseThrowExpression/CSharpUseThrowExpressionDiagnosticAnalyzer.cs b/...alyzers/CSharp/Analyzers/UseThrowExpression/CSharpUseThrowExpressionDiagnosticAnalyzer.cs
@@ -12,7 +12,7 @@
 namespace Microsoft.CodeAnalysis.CSharp.UseThrowExpression;
 
 [DiagnosticAnalyzer(LanguageNames.CSharp)]
-internal class CSharpUseThrowExpressionDiagnosticAnalyzer()
+internal sealed class CSharpUseThrowExpressionDiagnosticAnalyzer()
     : AbstractUseThrowExpressionDiagnosticAnalyzer(CSharpCodeStyleOptions.PreferThrowExpression)
 {
     protected override ISemanticFacts SemanticFacts

diff --git a/src/Analyzers/CSharp/Analyzers/UseTupleSwap/CSharpUseTupleSwapDiagnosticAnalyzer.cs b/src/Analyzers/CSharp/Analyzers/UseTupleSwap/CSharpUseTupleSwapDiagnosticAnalyzer.cs
@@ -30,7 +30,7 @@ namespace Microsoft.CodeAnalysis.CSharp.UseTupleSwap;
 /// 
 /// </summary>
 [DiagnosticAnalyzer(LanguageNames.CSharp)]
-internal class CSharpUseTupleSwapDiagnosticAnalyzer : AbstractBuiltInCodeStyleDiagnosticAnalyzer
+internal sealed class CSharpUseTupleSwapDiagnosticAnalyzer : AbstractBuiltInCodeStyleDiagnosticAnalyzer
 {
     public CSharpUseTupleSwapDiagnosticAnalyzer()
         : base(IDEDiagnosticIds.UseTupleSwapDiagnosticId,

diff --git a/...ers/CSharp/Analyzers/ValidateFormatString/CSharpValidateFormatStringDiagnosticAnalyzer.cs b/...ers/CSharp/Analyzers/ValidateFormatString/CSharpValidateFormatStringDiagnosticAnalyzer.cs
@@ -12,7 +12,7 @@
 namespace Microsoft.CodeAnalysis.CSharp.ValidateFormatString;
 
 [DiagnosticAnalyzer(LanguageNames.CSharp)]
-internal class CSharpValidateFormatStringDiagnosticAnalyzer :
+internal sealed class CSharpValidateFormatStringDiagnosticAnalyzer :
     AbstractValidateFormatStringDiagnosticAnalyzer<SyntaxKind>
 {
     protected override ISyntaxFacts GetSyntaxFacts()

diff --git a/src/Analyzers/CSharp/CodeFixes/ConvertToRecord/PositionalParameterInfo.cs b/src/Analyzers/CSharp/CodeFixes/ConvertToRecord/PositionalParameterInfo.cs
@@ -21,7 +21,7 @@ namespace Microsoft.CodeAnalysis.CSharp.ConvertToRecord;
 /// Null iff <see cref="IsInherited"/> is true</param>
 /// <param name="Symbol">Symbol of the property</param>
 /// <param name="KeepAsOverride">Whether we should keep the original declaration present</param>
-internal record PositionalParameterInfo(
+internal sealed record PositionalParameterInfo(
     PropertyDeclarationSyntax? Declaration,
     IPropertySymbol Symbol,
     bool KeepAsOverride)

diff --git a/...CSharp/CodeFixes/UseConditionalExpression/MultiLineConditionalExpressionFormattingRule.cs b/...CSharp/CodeFixes/UseConditionalExpression/MultiLineConditionalExpressionFormattingRule.cs
@@ -22,7 +22,7 @@ namespace Microsoft.CodeAnalysis.CSharp.UseConditionalExpression;
 /// 
 /// i.e. both branches will be on a newline, indented once from the parent indentation.
 /// </summary>
-internal class MultiLineConditionalExpressionFormattingRule : AbstractFormattingRule
+internal sealed class MultiLineConditionalExpressionFormattingRule : AbstractFormattingRule
 {
     public static readonly AbstractFormattingRule Instance = new MultiLineConditionalExpressionFormattingRule();
 

diff --git a/src/Analyzers/CSharp/Tests/AddAnonymousTypeMemberName/AddAnonymousTypeMemberNameTests.cs b/src/Analyzers/CSharp/Tests/AddAnonymousTypeMemberName/AddAnonymousTypeMemberNameTests.cs
@@ -14,7 +14,7 @@
 namespace Microsoft.CodeAnalysis.Editor.CSharp.UnitTests.AddAnonymousTypeMemberName;
 
 [Trait(Traits.Feature, Traits.Features.CodeActionsAddAnonymousTypeMemberName)]
-public class AddAnonymousTypeMemberNameTests : AbstractCSharpDiagnosticProviderBasedUserDiagnosticTest_NoEditor
+public sealed class AddAnonymousTypeMemberNameTests : AbstractCSharpDiagnosticProviderBasedUserDiagnosticTest_NoEditor
 {
     public AddAnonymousTypeMemberNameTests(ITestOutputHelper logger)
        : base(logger)

diff --git a/src/Analyzers/CSharp/Tests/AddBraces/AddBracesTests.cs b/src/Analyzers/CSharp/Tests/AddBraces/AddBracesTests.cs
@@ -17,7 +17,7 @@
 namespace Microsoft.CodeAnalysis.Editor.CSharp.UnitTests.AddBraces;
 
 [Trait(Traits.Feature, Traits.Features.CodeActionsAddBraces)]
-public partial class AddBracesTests : AbstractCSharpDiagnosticProviderBasedUserDiagnosticTest_NoEditor
+public sealed partial class AddBracesTests : AbstractCSharpDiagnosticProviderBasedUserDiagnosticTest_NoEditor
 {
     public AddBracesTests(ITestOutputHelper logger)
        : base(logger)

diff --git a/src/Analyzers/CSharp/Tests/AddExplicitCast/AddExplicitCastTests.cs b/src/Analyzers/CSharp/Tests/AddExplicitCast/AddExplicitCastTests.cs
@@ -16,7 +16,7 @@
 namespace Microsoft.CodeAnalysis.Editor.CSharp.UnitTests.Diagnostics.AddExplicitCast;
 
 [Trait(Traits.Feature, Traits.Features.CodeActionsAddExplicitCast)]
-public partial class AddExplicitCastTests(ITestOutputHelper logger)
+public sealed partial class AddExplicitCastTests(ITestOutputHelper logger)
     : AbstractCSharpDiagnosticProviderBasedUserDiagnosticTest_NoEditor(logger)
 {
     internal override (DiagnosticAnalyzer?, CodeFixProvider) CreateDiagnosticProviderAndFixer(Workspace workspace)

diff --git a/src/Analyzers/CSharp/Tests/AliasAmbiguousType/AliasAmbiguousTypeTests.cs b/src/Analyzers/CSharp/Tests/AliasAmbiguousType/AliasAmbiguousTypeTests.cs
@@ -19,7 +19,7 @@
 namespace Microsoft.CodeAnalysis.Editor.CSharp.UnitTests.AliasAmbiguousType;
 
 [Trait(Traits.Feature, Traits.Features.CodeActionsAliasAmbiguousType)]
-public class AliasAmbiguousTypeTests : AbstractCSharpDiagnosticProviderBasedUserDiagnosticTest_NoEditor
+public sealed class AliasAmbiguousTypeTests : AbstractCSharpDiagnosticProviderBasedUserDiagnosticTest_NoEditor
 {
     public AliasAmbiguousTypeTests(ITestOutputHelper logger)
        : base(logger)

diff --git a/src/Analyzers/CSharp/Tests/AssignOutParameters/AssignOutParametersAboveReturnTests.cs b/src/Analyzers/CSharp/Tests/AssignOutParameters/AssignOutParametersAboveReturnTests.cs
@@ -16,7 +16,7 @@ namespace Microsoft.CodeAnalysis.Editor.CSharp.UnitTests.AssignOutParameters;
     AssignOutParametersAboveReturnCodeFixProvider>;
 
 [Trait(Traits.Feature, Traits.Features.CodeActionsAssignOutParameters)]
-public class AssignOutParametersAboveReturnTests
+public sealed class AssignOutParametersAboveReturnTests
 {
     [Fact]
     public async Task TestForSimpleReturn()

diff --git a/src/Analyzers/CSharp/Tests/AssignOutParameters/AssignOutParametersAtStartTests.cs b/src/Analyzers/CSharp/Tests/AssignOutParameters/AssignOutParametersAtStartTests.cs
@@ -21,7 +21,7 @@ namespace Microsoft.CodeAnalysis.Editor.CSharp.UnitTests.AssignOutParameters;
 /// such.
 /// </summary>
 [Trait(Traits.Feature, Traits.Features.CodeActionsAssignOutParameters)]
-public class AssignOutParametersAtStartTests
+public sealed class AssignOutParametersAtStartTests
 {
     [Fact]
     public async Task TestForSimpleReturn()

diff --git a/...SharpAddParenthesesAroundConditionalExpressionInInterpolatedStringCodeFixProviderTests.cs b/...SharpAddParenthesesAroundConditionalExpressionInInterpolatedStringCodeFixProviderTests.cs
@@ -14,7 +14,7 @@
 namespace Microsoft.CodeAnalysis.Editor.CSharp.UnitTests.ConditionalExpressionInStringInterpolation;
 
 [Trait(Traits.Feature, Traits.Features.CodeActionsAddParenthesesAroundConditionalExpressionInInterpolatedString)]
-public class CSharpAddParenthesesAroundConditionalExpressionInInterpolatedStringCodeFixProviderTests : AbstractCSharpDiagnosticProviderBasedUserDiagnosticTest_NoEditor
+public sealed class CSharpAddParenthesesAroundConditionalExpressionInInterpolatedStringCodeFixProviderTests : AbstractCSharpDiagnosticProviderBasedUserDiagnosticTest_NoEditor
 {
     public CSharpAddParenthesesAroundConditionalExpressionInInterpolatedStringCodeFixProviderTests(ITestOutputHelper logger)
        : base(logger)

diff --git a/src/Analyzers/CSharp/Tests/ConflictMarkerResolution/ConflictMarkerResolutionTests.cs b/src/Analyzers/CSharp/Tests/ConflictMarkerResolution/ConflictMarkerResolutionTests.cs
@@ -16,7 +16,7 @@ namespace Microsoft.CodeAnalysis.Editor.CSharp.UnitTests.ConflictMarkerResolutio
 using VerifyCS = CSharpCodeFixVerifier<EmptyDiagnosticAnalyzer, CSharpResolveConflictMarkerCodeFixProvider>;
 
 [Trait(Traits.Feature, Traits.Features.CodeActionsResolveConflictMarker)]
-public class ConflictMarkerResolutionTests
+public sealed class ConflictMarkerResolutionTests
 {
     [Fact]
     public async Task TestTakeTop1()

diff --git a/src/Analyzers/CSharp/Tests/ConvertNamespace/ConvertToBlockScopedNamespaceAnalyzerTests.cs b/src/Analyzers/CSharp/Tests/ConvertNamespace/ConvertToBlockScopedNamespaceAnalyzerTests.cs
@@ -17,7 +17,7 @@ namespace Microsoft.CodeAnalysis.Editor.CSharp.UnitTests.ConvertNamespace;
 
 using VerifyCS = CSharpCodeFixVerifier<ConvertToBlockScopedNamespaceDiagnosticAnalyzer, ConvertNamespaceCodeFixProvider>;
 
-public class ConvertToBlockScopedNamespaceAnalyzerTests
+public sealed class ConvertToBlockScopedNamespaceAnalyzerTests
 {
     public static IEnumerable<object[]> EndOfDocumentSequences
     {

diff --git a/...Tests/ConvertSwitchStatementToExpression/ConvertSwitchStatementToExpressionFixAllTests.cs b/...Tests/ConvertSwitchStatementToExpression/ConvertSwitchStatementToExpressionFixAllTests.cs
@@ -16,7 +16,7 @@ namespace Microsoft.CodeAnalysis.Editor.CSharp.UnitTests.ConvertSwitchStatementT
     ConvertSwitchStatementToExpressionCodeFixProvider>;
 
 [Trait(Traits.Feature, Traits.Features.CodeActionsConvertSwitchStatementToExpression)]
-public class ConvertSwitchStatementToExpressionFixAllTests
+public sealed class ConvertSwitchStatementToExpressionFixAllTests
 {
     [Fact]
     public async Task TestNested_01()