diff --git a/src/Docfx.App/Helpers/DocumentBuilderWrapper.cs b/src/Docfx.App/Helpers/DocumentBuilderWrapper.cs
index bc542a514fb..2bafb81bef6 100644
--- a/src/Docfx.App/Helpers/DocumentBuilderWrapper.cs
+++ b/src/Docfx.App/Helpers/DocumentBuilderWrapper.cs
@@ -23,7 +23,7 @@ public static void BuildDocument(BuildJsonConfig config, BuildOptions options, T
         // Ensure "_enableSearch" adds the right post processor
         if (metadata != null && metadata.TryGetValue("_enableSearch", out object value))
         {
-            if (value is bool isSearchable && isSearchable && !postProcessorNames.Contains("ExtractSearchIndex"))
+            if (value is true && !postProcessorNames.Contains("ExtractSearchIndex"))
             {
                 postProcessorNames = postProcessorNames.Add("ExtractSearchIndex");
             }
diff --git a/src/Docfx.Build.Common/ModelAttributeHandlers/Handlers/BaseModelAttributeHandler.cs b/src/Docfx.Build.Common/ModelAttributeHandlers/Handlers/BaseModelAttributeHandler.cs
index 847a3da6406..1178c9062bf 100644
--- a/src/Docfx.Build.Common/ModelAttributeHandlers/Handlers/BaseModelAttributeHandler.cs
+++ b/src/Docfx.Build.Common/ModelAttributeHandlers/Handlers/BaseModelAttributeHandler.cs
@@ -78,7 +78,7 @@ public object Handle(object obj, HandleModelAttributesContext context)
 
     protected virtual bool ShouldHandle(object currentObj, object declaringObject, PropInfo currentPropInfo, HandleModelAttributesContext context)
     {
-        return currentPropInfo != null && currentPropInfo.Attr != null;
+        return currentPropInfo is {Attr: not null};
     }
 
     /// <summary>
diff --git a/src/Docfx.Build.ManagedReference/BuildOutputs/ApiReferenceBuildOutput.cs b/src/Docfx.Build.ManagedReference/BuildOutputs/ApiReferenceBuildOutput.cs
index e168b7949b4..14416d04deb 100644
--- a/src/Docfx.Build.ManagedReference/BuildOutputs/ApiReferenceBuildOutput.cs
+++ b/src/Docfx.Build.ManagedReference/BuildOutputs/ApiReferenceBuildOutput.cs
@@ -300,7 +300,7 @@ public void Expand(Dictionary<string, ApiReferenceBuildOutput> references, strin
 
     public static List<ApiLanguageValuePair> GetSpecNames(string xref, string[] supportedLanguages, SortedList<string, List<SpecViewModel>> specs = null)
     {
-        if (specs != null && specs.Count > 0)
+        if (specs is {Count: > 0})
         {
             return (from spec in specs
                     where supportedLanguages.Contains(spec.Key)
diff --git a/src/Docfx.Build.RestApi/BuildRestApiDocument.cs b/src/Docfx.Build.RestApi/BuildRestApiDocument.cs
index 75d60adb8d8..479fa53a900 100644
--- a/src/Docfx.Build.RestApi/BuildRestApiDocument.cs
+++ b/src/Docfx.Build.RestApi/BuildRestApiDocument.cs
@@ -102,7 +102,7 @@ private static void MarkupRecursive(JToken jToken, IHostService host, FileModel
             {
                 if (MarkupKeys.Contains(pair.Key) && pair.Value != null)
                 {
-                    if (pair.Value is JValue jValue && jValue.Type == JTokenType.String)
+                    if (pair.Value is JValue {Type: JTokenType.String} jValue)
                     {
                         jObject[pair.Key] = Markup(host, (string)jValue, model, filter);
                     }
diff --git a/src/Docfx.Build.RestApi/RestApiDocumentProcessor.cs b/src/Docfx.Build.RestApi/RestApiDocumentProcessor.cs
index 8e6e4a5e608..fe922ad87a2 100644
--- a/src/Docfx.Build.RestApi/RestApiDocumentProcessor.cs
+++ b/src/Docfx.Build.RestApi/RestApiDocumentProcessor.cs
@@ -211,7 +211,7 @@ private static bool IsSwaggerFile(string filePath)
             if (jObject.TryGetValue("swagger", out JToken swaggerValue))
             {
                 var swaggerString = (string)swaggerValue;
-                if (swaggerString != null && swaggerString.Equals("2.0"))
+                if (swaggerString is "2.0")
                 {
                     return true;
                 }
diff --git a/src/Docfx.Build.SchemaDriven/Models/JsonPointer.cs b/src/Docfx.Build.SchemaDriven/Models/JsonPointer.cs
index 5b1284e1ea1..99bb7ddba2d 100644
--- a/src/Docfx.Build.SchemaDriven/Models/JsonPointer.cs
+++ b/src/Docfx.Build.SchemaDriven/Models/JsonPointer.cs
@@ -49,7 +49,7 @@ public JsonPointer GetParentPointer()
     public static bool TryCreate(string raw, out JsonPointer pointer)
     {
         pointer = null;
-        if (raw != null && raw.Length > 0 && raw[0] != '/')
+        if (raw is {Length: > 0} && raw[0] != '/')
         {
             return false;
         }
diff --git a/src/Docfx.Build.SchemaDriven/Processors/FileInterpreter.cs b/src/Docfx.Build.SchemaDriven/Processors/FileInterpreter.cs
index 1874563298d..d67f99742ed 100644
--- a/src/Docfx.Build.SchemaDriven/Processors/FileInterpreter.cs
+++ b/src/Docfx.Build.SchemaDriven/Processors/FileInterpreter.cs
@@ -19,7 +19,7 @@ public FileInterpreter(bool exportFileLink, bool updateValue)
 
     public bool CanInterpret(BaseSchema schema)
     {
-        return schema != null && schema.ContentType == ContentType.File;
+        return schema is {ContentType: ContentType.File};
     }
 
     public object Interpret(BaseSchema schema, object value, IProcessContext context, string path)
diff --git a/src/Docfx.Build.SchemaDriven/Processors/HrefInterpreter.cs b/src/Docfx.Build.SchemaDriven/Processors/HrefInterpreter.cs
index e6c95f1def9..64fee4703e3 100644
--- a/src/Docfx.Build.SchemaDriven/Processors/HrefInterpreter.cs
+++ b/src/Docfx.Build.SchemaDriven/Processors/HrefInterpreter.cs
@@ -21,7 +21,7 @@ public HrefInterpreter(bool exportFileLink, bool updateValue, string siteHostNam
 
     public bool CanInterpret(BaseSchema schema)
     {
-        return schema != null && schema.ContentType == ContentType.Href;
+        return schema is {ContentType: ContentType.Href};
     }
 
     public object Interpret(BaseSchema schema, object value, IProcessContext context, string path)
diff --git a/src/Docfx.Build.SchemaDriven/Processors/MarkdownInterpreter.cs b/src/Docfx.Build.SchemaDriven/Processors/MarkdownInterpreter.cs
index f2b8c36260f..2ac605ee96e 100644
--- a/src/Docfx.Build.SchemaDriven/Processors/MarkdownInterpreter.cs
+++ b/src/Docfx.Build.SchemaDriven/Processors/MarkdownInterpreter.cs
@@ -9,7 +9,7 @@ public class MarkdownInterpreter : IInterpreter
 {
     public bool CanInterpret(BaseSchema schema)
     {
-        return schema != null && schema.ContentType == ContentType.Markdown;
+        return schema is {ContentType: ContentType.Markdown};
     }
 
     public object Interpret(BaseSchema schema, object value, IProcessContext context, string path)
diff --git a/src/Docfx.Build.SchemaDriven/Processors/XrefInterpreter.cs b/src/Docfx.Build.SchemaDriven/Processors/XrefInterpreter.cs
index a865871c960..e4c0f1618f3 100644
--- a/src/Docfx.Build.SchemaDriven/Processors/XrefInterpreter.cs
+++ b/src/Docfx.Build.SchemaDriven/Processors/XrefInterpreter.cs
@@ -19,7 +19,7 @@ public XrefInterpreter(bool aggregateXrefs, bool resolveXref)
 
     public bool CanInterpret(BaseSchema schema)
     {
-        return schema != null && schema.ContentType == ContentType.Xref;
+        return schema is {ContentType: ContentType.Xref};
     }
 
     public object Interpret(BaseSchema schema, object value, IProcessContext context, string path)
diff --git a/src/Docfx.Build/TableOfContents/TocDocumentProcessor.cs b/src/Docfx.Build/TableOfContents/TocDocumentProcessor.cs
index 85edc54ffdb..79172edce58 100644
--- a/src/Docfx.Build/TableOfContents/TocDocumentProcessor.cs
+++ b/src/Docfx.Build/TableOfContents/TocDocumentProcessor.cs
@@ -91,7 +91,7 @@ private void UpdateTocItemHref(TocItemViewModel toc, FileModel model, IDocumentB
         toc.OriginalTopicHref = null;
 
         includedFrom = toc.IncludedFrom ?? includedFrom;
-        if (toc.Items != null && toc.Items.Count > 0)
+        if (toc.Items is {Count: > 0})
         {
             foreach (var item in toc.Items)
             {
diff --git a/src/Docfx.Build/TableOfContents/TocResolver.cs b/src/Docfx.Build/TableOfContents/TocResolver.cs
index 242a7bddbec..6ea34f31a3b 100644
--- a/src/Docfx.Build/TableOfContents/TocResolver.cs
+++ b/src/Docfx.Build/TableOfContents/TocResolver.cs
@@ -122,7 +122,7 @@ private TocItemInfo ResolveItemCore(TocItemInfo wrapper, Stack<FileAndType> stac
         {
             case HrefType.AbsolutePath:
             case HrefType.RelativeFile:
-                if (item.Items != null && item.Items.Count > 0)
+                if (item.Items is {Count: > 0})
                 {
                     item.Items = new List<TocItemViewModel>(from i in item.Items
                                                             select ResolveItem(new TocItemInfo(file, i), stack) into r
diff --git a/src/Docfx.Build/TableOfContents/TocRestructureUtility.cs b/src/Docfx.Build/TableOfContents/TocRestructureUtility.cs
index c22f925242f..ead7255750e 100644
--- a/src/Docfx.Build/TableOfContents/TocRestructureUtility.cs
+++ b/src/Docfx.Build/TableOfContents/TocRestructureUtility.cs
@@ -28,7 +28,7 @@ private static void RestructureCore(TocItemViewModel item, List<TocItemViewModel
             }
         }
 
-        if (item.Items != null && item.Items.Count > 0)
+        if (item.Items is {Count: > 0})
         {
             var parentItems = new List<TocItemViewModel>(item.Items);
             foreach (var i in item.Items)
diff --git a/src/Docfx.Build/TemplateProcessors/TemplateManager.cs b/src/Docfx.Build/TemplateProcessors/TemplateManager.cs
index 760989cb1f8..d4345e937f4 100644
--- a/src/Docfx.Build/TemplateProcessors/TemplateManager.cs
+++ b/src/Docfx.Build/TemplateProcessors/TemplateManager.cs
@@ -78,7 +78,7 @@ private IEnumerable<string> GetTemplateDirectories(IEnumerable<string> names)
 
     public void ProcessTheme(string outputDirectory, bool overwrite)
     {
-        if (_themes != null && _themes.Count > 0)
+        if (_themes is {Count: > 0})
         {
             TryExportResourceFiles(_themes, outputDirectory, overwrite);
             Logger.LogInfo($"Theme(s) {_themes.ToDelimitedString()} applied.");
diff --git a/src/Docfx.Build/XRefMaps/XRefArchiveBuilder.cs b/src/Docfx.Build/XRefMaps/XRefArchiveBuilder.cs
index 0a43a29fa30..61d2f99d36e 100644
--- a/src/Docfx.Build/XRefMaps/XRefArchiveBuilder.cs
+++ b/src/Docfx.Build/XRefMaps/XRefArchiveBuilder.cs
@@ -53,7 +53,7 @@ private async Task<string> DownloadCoreAsync(Uri uri, XRefArchive xa, Cancellati
         //   Sort is not needed if `map.Sorted == true`.
         //   But there are some xrefmap files that is not propery sorted by using InvariantCulture.
         //   (e.g. Unity xrefmap that maintained by community)
-        if (map.References != null && map.References.Count > 0)
+        if (map.References is {Count: > 0})
         {
             map.References.Sort(XRefSpecUidComparer.Instance);
             map.Sorted = true;
diff --git a/src/Docfx.Common/Path/RelativePath.cs b/src/Docfx.Common/Path/RelativePath.cs
index a804d5db46f..8e783c36c42 100644
--- a/src/Docfx.Common/Path/RelativePath.cs
+++ b/src/Docfx.Common/Path/RelativePath.cs
@@ -54,11 +54,10 @@ public static RelativePath FromUrl(string path)
     public static bool IsRelativePath(string path)
     {
         // TODO : to merge with the PathUtility one
-        return path != null &&
-            path.Length > 0 &&
-            path[0] != '/' &&
-            path[0] != '\\' &&
-            path.IndexOfAny(PathUtility.InvalidPathChars) == -1;
+        return path is {Length: > 0} &&
+               path[0] != '/' &&
+               path[0] != '\\' &&
+               path.IndexOfAny(PathUtility.InvalidPathChars) == -1;
     }
 
     public static RelativePath Parse(string path) => TryParseCore(path, true);
diff --git a/src/Docfx.Dotnet/DotnetApiCatalog.Toc.cs b/src/Docfx.Dotnet/DotnetApiCatalog.Toc.cs
index 5dcb7ecd79e..788da38ef94 100644
--- a/src/Docfx.Dotnet/DotnetApiCatalog.Toc.cs
+++ b/src/Docfx.Dotnet/DotnetApiCatalog.Toc.cs
@@ -61,7 +61,7 @@ IEnumerable<TocNode> CreateToc(ISymbol symbol, Compilation compilation)
 
             switch (symbol)
             {
-                case INamespaceSymbol ns when ns.IsGlobalNamespace:
+                case INamespaceSymbol {IsGlobalNamespace: true} ns:
                     foreach (var child in ns.GetNamespaceMembers())
                         foreach (var item in CreateToc(child, compilation))
                             yield return item;
@@ -248,7 +248,7 @@ void InsertCategory(TocNodeType type, string name)
                     case CategoryLayout.Nested:
                         {
                             // Skip when parent node is category node.
-                            if (parentTocNode != null && parentTocNode.type == TocNodeType.None)
+                            if (parentTocNode is {type: TocNodeType.None})
                                 return;
 
                             // If items contains specified type node. Create new TocNode for category. and move related node to child node.
diff --git a/src/Docfx.Dotnet/ManagedReference/Resolvers/NormalizeSyntax.cs b/src/Docfx.Dotnet/ManagedReference/Resolvers/NormalizeSyntax.cs
index 1fe8e00c895..61794226839 100644
--- a/src/Docfx.Dotnet/ManagedReference/Resolvers/NormalizeSyntax.cs
+++ b/src/Docfx.Dotnet/ManagedReference/Resolvers/NormalizeSyntax.cs
@@ -17,7 +17,7 @@ public void Run(MetadataModel yaml, ResolverContext context)
             (member, parent) =>
             {
                 // get all the possible places where link is possible
-                if (member.Syntax != null && member.Syntax.Content != null)
+                if (member.Syntax is {Content: not null})
                 {
                     SyntaxLanguage[] keys = new SyntaxLanguage[member.Syntax.Content.Count];
                     member.Syntax.Content.Keys.CopyTo(keys, 0);
diff --git a/src/Docfx.Dotnet/ManagedReference/Resolvers/ResolveReference.cs b/src/Docfx.Dotnet/ManagedReference/Resolvers/ResolveReference.cs
index 074c5318ea6..1b59b26ee8c 100644
--- a/src/Docfx.Dotnet/ManagedReference/Resolvers/ResolveReference.cs
+++ b/src/Docfx.Dotnet/ManagedReference/Resolvers/ResolveReference.cs
@@ -27,7 +27,7 @@ public void Run(MetadataModel yaml, ResolverContext context)
                     page = parent;
                     current.References = null;
                 }
-                if (documentReferences != null && documentReferences.Count > 0)
+                if (documentReferences is {Count: > 0})
                 {
                     foreach (var key in documentReferences.Keys)
                     {
diff --git a/src/Docfx.Dotnet/ManagedReference/Resolvers/SetDerivedClass.cs b/src/Docfx.Dotnet/ManagedReference/Resolvers/SetDerivedClass.cs
index 8a9401b2a32..c812f1a6e0d 100644
--- a/src/Docfx.Dotnet/ManagedReference/Resolvers/SetDerivedClass.cs
+++ b/src/Docfx.Dotnet/ManagedReference/Resolvers/SetDerivedClass.cs
@@ -11,7 +11,7 @@ internal class SetDerivedClass : IResolverPipeline
 
     public void Run(MetadataModel yaml, ResolverContext context)
     {
-        if (yaml.Members != null && yaml.Members.Count > 0)
+        if (yaml.Members is {Count: > 0})
         {
             UpdateDerivedClassMapping(yaml.Members, context.References);
             AppendDerivedClass(yaml.Members);
@@ -23,7 +23,7 @@ private void UpdateDerivedClassMapping(List<MetadataItem> items, Dictionary<stri
         foreach (var item in items ?? Enumerable.Empty<MetadataItem>())
         {
             var inheritance = item.Inheritance;
-            if (inheritance != null && inheritance.Count > 0)
+            if (inheritance is {Count: > 0})
             {
                 var superClass = inheritance[inheritance.Count - 1];
 
diff --git a/src/Docfx.Dotnet/ManagedReference/Visitors/SymbolVisitorAdapter.cs b/src/Docfx.Dotnet/ManagedReference/Visitors/SymbolVisitorAdapter.cs
index b283661a9a3..0ede8bde10a 100644
--- a/src/Docfx.Dotnet/ManagedReference/Visitors/SymbolVisitorAdapter.cs
+++ b/src/Docfx.Dotnet/ManagedReference/Visitors/SymbolVisitorAdapter.cs
@@ -238,7 +238,7 @@ public override MetadataItem VisitMethod(IMethodSymbol symbol)
         }
         _generator.GenerateSyntax(symbol, result.Syntax, _filter);
 
-        if (symbol.IsOverride && symbol.OverriddenMethod != null)
+        if (symbol is {IsOverride: true, OverriddenMethod: not null})
         {
             result.Overridden = AddSpecReference(symbol.OverriddenMethod, typeGenericParameters, methodGenericParameters);
         }
@@ -296,7 +296,7 @@ public override MetadataItem VisitEvent(IEventSymbol symbol)
 
         var typeGenericParameters = symbol.ContainingType.IsGenericType ? symbol.ContainingType.Accept(TypeGenericParameterNameVisitor.Instance) : EmptyListOfString;
 
-        if (symbol.IsOverride && symbol.OverriddenEvent != null)
+        if (symbol is {IsOverride: true, OverriddenEvent: not null})
         {
             result.Overridden = AddSpecReference(symbol.OverriddenEvent, typeGenericParameters);
         }
@@ -350,7 +350,7 @@ public override MetadataItem VisitProperty(IPropertySymbol symbol)
             Debug.Assert(result.Syntax.Return.Type != null);
         }
 
-        if (symbol.IsOverride && symbol.OverriddenProperty != null)
+        if (symbol is {IsOverride: true, OverriddenProperty: not null})
         {
             result.Overridden = AddSpecReference(symbol.OverriddenProperty, typeGenericParameters);
         }
diff --git a/src/Docfx.Dotnet/ManagedReference/Visitors/VisitorHelper.cs b/src/Docfx.Dotnet/ManagedReference/Visitors/VisitorHelper.cs
index d60fbf4f395..0db6a1a587f 100644
--- a/src/Docfx.Dotnet/ManagedReference/Visitors/VisitorHelper.cs
+++ b/src/Docfx.Dotnet/ManagedReference/Visitors/VisitorHelper.cs
@@ -29,7 +29,7 @@ public static string GetId(ISymbol symbol)
             return null;
         }
 
-        if (symbol is INamespaceSymbol namespaceSymbol && namespaceSymbol.IsGlobalNamespace)
+        if (symbol is INamespaceSymbol {IsGlobalNamespace: true})
         {
             return GlobalNamespaceId;
         }
diff --git a/src/Docfx.Dotnet/Parsers/XmlComment.cs b/src/Docfx.Dotnet/Parsers/XmlComment.cs
index 1cfc7312d61..52b3b1d6a29 100644
--- a/src/Docfx.Dotnet/Parsers/XmlComment.cs
+++ b/src/Docfx.Dotnet/Parsers/XmlComment.cs
@@ -356,7 +356,7 @@ private void ResolveCrefLink(XNode node, string nodeSelector, Action<string, str
             if (!success)
             {
                 var detailedInfo = new StringBuilder();
-                if (_context != null && _context.Source != null)
+                if (_context is {Source: not null})
                 {
                     if (!string.IsNullOrEmpty(_context.Source.Name))
                     {
@@ -631,7 +631,7 @@ static void MarkdownXmlDecode(MarkdownObject node)
                         MarkdownXmlDecode(child);
                     break;
 
-                case LeafBlock leafBlock when leafBlock.Inline is not null:
+                case LeafBlock {Inline: not null} leafBlock:
                     foreach (var child in leafBlock.Inline)
                         MarkdownXmlDecode(child);
                     break;
diff --git a/src/Docfx.Dotnet/SymbolFilter.cs b/src/Docfx.Dotnet/SymbolFilter.cs
index d0ce53fabc4..47685377b9d 100644
--- a/src/Docfx.Dotnet/SymbolFilter.cs
+++ b/src/Docfx.Dotnet/SymbolFilter.cs
@@ -95,7 +95,7 @@ bool IncludeAttributeDefault(ISymbol symbol)
     private bool IsSymbolAccessible(ISymbol symbol)
     {
         // TODO: should we include implicitly declared members like constructors? They are part of the API contract.
-        if (symbol.IsImplicitlyDeclared && symbol.Kind is not SymbolKind.Namespace)
+        if (symbol is {IsImplicitlyDeclared: true, Kind: not SymbolKind.Namespace})
             return false;
 
         if (_config.IncludeExplicitInterfaceImplementations &&
diff --git a/src/Docfx.Dotnet/SymbolFormatter.Syntax.cs b/src/Docfx.Dotnet/SymbolFormatter.Syntax.cs
index 737ab8e086d..9e8db3d1da9 100644
--- a/src/Docfx.Dotnet/SymbolFormatter.Syntax.cs
+++ b/src/Docfx.Dotnet/SymbolFormatter.Syntax.cs
@@ -368,7 +368,7 @@ private void AddTypedConstant(TypedConstant typedConstant)
                     AddPunctuation(")");
                     break;
 
-                case TypedConstantKind.Array when !typedConstant.IsNull && typedConstant.Type is not null:
+                case TypedConstantKind.Array when typedConstant is {IsNull: false, Type: not null}:
                     AddKeyword("new", "New");
                     AddSpace();
                     AddTypeName(typedConstant.Type);
@@ -460,7 +460,7 @@ private void AddEnumConstant(TypedConstant typedConstant)
 
         private bool ExpandEnumClassName(ISymbol symbol, SymbolDisplayPart part)
         {
-            if (symbol.Kind != SymbolKind.Field && part.Kind == SymbolDisplayPartKind.EnumMemberName && part.Symbol is not null)
+            if (symbol.Kind != SymbolKind.Field && part is {Kind: SymbolDisplayPartKind.EnumMemberName, Symbol: not null})
             {
                 _parts.Add(new(SymbolDisplayPartKind.EnumName, part.Symbol.ContainingSymbol, part.Symbol.ContainingSymbol.Name));
                 _parts.Add(new(SymbolDisplayPartKind.Punctuation, null, "."));
@@ -472,7 +472,7 @@ private bool ExpandEnumClassName(ISymbol symbol, SymbolDisplayPart part)
 
         private bool StaticClassToVBModule(ISymbol symbol, SymbolDisplayPart part)
         {
-            if (Language is SyntaxLanguage.VB && symbol.IsStatic && symbol.Kind is SymbolKind.NamedType &&
+            if (Language is SyntaxLanguage.VB && symbol is {IsStatic: true, Kind: SymbolKind.NamedType} &&
                 part.Kind == SymbolDisplayPartKind.Keyword && part.ToString() == "Class")
             {
                 _parts.Add(new(SymbolDisplayPartKind.Keyword, null, "Module"));
diff --git a/src/Docfx.Dotnet/SymbolFormatter.cs b/src/Docfx.Dotnet/SymbolFormatter.cs
index b155a80d729..0e6bf1b496d 100644
--- a/src/Docfx.Dotnet/SymbolFormatter.cs
+++ b/src/Docfx.Dotnet/SymbolFormatter.cs
@@ -131,7 +131,7 @@ LinkItem ToLinkItem(SymbolDisplayPart part)
             if (symbol is null || part.Kind is SymbolDisplayPartKind.TypeParameterName)
                 return new() { DisplayName = part.ToString() };
 
-            if (symbol is INamedTypeSymbol type && type.IsGenericType)
+            if (symbol is INamedTypeSymbol {IsGenericType: true} type)
                 symbol = type.ConstructedFrom;
 
             return new()
diff --git a/src/Docfx.Dotnet/SymbolHelper.cs b/src/Docfx.Dotnet/SymbolHelper.cs
index bc61ab74cb8..d49889a6a32 100644
--- a/src/Docfx.Dotnet/SymbolHelper.cs
+++ b/src/Docfx.Dotnet/SymbolHelper.cs
@@ -33,7 +33,7 @@ public static bool IsMember(this ISymbol symbol)
 
     public static bool IsClass(this ISymbol symbol)
     {
-        return symbol.Kind is SymbolKind.NamedType && symbol is INamedTypeSymbol type && type.TypeKind is TypeKind.Class;
+        return symbol.Kind is SymbolKind.NamedType && symbol is INamedTypeSymbol {TypeKind: TypeKind.Class};
     }
 
     public static bool IsEnumMember(this ISymbol symbol)
diff --git a/src/Docfx.Dotnet/SymbolUrlResolver.MSLearn.cs b/src/Docfx.Dotnet/SymbolUrlResolver.MSLearn.cs
index b25a9624801..0faf52089ff 100644
--- a/src/Docfx.Dotnet/SymbolUrlResolver.MSLearn.cs
+++ b/src/Docfx.Dotnet/SymbolUrlResolver.MSLearn.cs
@@ -109,7 +109,7 @@ internal static string GetUrlFragmentFromUid(string uid)
                 case '}':
                     sb.Append("))");
                     break;
-                case char c when (c >= 'a' && c <= 'z') || (c >= '0' && c <= '9'):
+                case char and (>= 'a' and <= 'z' or >= '0' and <= '9'):
                 case '(' or ')' or '*' or '@':
                     sb.Append(ch);
                     break;
diff --git a/src/Docfx.Dotnet/YamlViewModelExtensions.cs b/src/Docfx.Dotnet/YamlViewModelExtensions.cs
index b24dba95762..e1690b0bce4 100644
--- a/src/Docfx.Dotnet/YamlViewModelExtensions.cs
+++ b/src/Docfx.Dotnet/YamlViewModelExtensions.cs
@@ -180,7 +180,7 @@ private static ReferenceViewModel ToReferenceViewModel(KeyValuePair<string, Refe
             Parent = model.Value.Parent,
             Definition = model.Value.Definition,
         };
-        if (model.Value.NameParts != null && model.Value.NameParts.Count > 0)
+        if (model.Value.NameParts is {Count: > 0})
         {
             result.Name = GetName(model.Value.NameParts, SyntaxLanguage.Default);
             var nameForCSharp = GetName(model.Value.NameParts, SyntaxLanguage.CSharp);
@@ -270,7 +270,7 @@ public static ItemViewModel ToItemViewModel(this MetadataItem model, ExtractMeta
             Attributes = model.Attributes,
         };
 
-        if (model.Parent != null && model.Parent.Name != null && !model.Name.StartsWith(model.Parent.Name))
+        if (model.Parent is {Name: not null} && !model.Name.StartsWith(model.Parent.Name))
         {
             result.Id = model.Name.Substring(model.Name.LastIndexOf('.') + 1);
         }
@@ -330,7 +330,7 @@ public static SyntaxDetailViewModel ToSyntaxDetailViewModel(this SyntaxDetail mo
             TypeParameters = model.TypeParameters,
             Return = model.Return,
         };
-        if (model.Content != null && model.Content.Count > 0)
+        if (model.Content is {Count: > 0})
         {
             result.Content = model.Content.GetLanguageProperty(SyntaxLanguage.Default);
             var contentForCSharp = model.Content.GetLanguageProperty(SyntaxLanguage.CSharp);
@@ -379,7 +379,7 @@ public static TValue GetLanguageProperty<TValue>(this SortedList<SyntaxLanguage,
 
     private static void AddChildren(MetadataItem model, PageViewModel result, ExtractMetadataConfig config)
     {
-        if (model.Items != null && model.Items.Count > 0)
+        if (model.Items is {Count: > 0})
         {
             foreach (var item in model.Items)
             {
diff --git a/src/Docfx.MarkdigEngine.Extensions/Aggregator/TabGroupAggregator.cs b/src/Docfx.MarkdigEngine.Extensions/Aggregator/TabGroupAggregator.cs
index 6c10611f183..b2d531fccd1 100644
--- a/src/Docfx.MarkdigEngine.Extensions/Aggregator/TabGroupAggregator.cs
+++ b/src/Docfx.MarkdigEngine.Extensions/Aggregator/TabGroupAggregator.cs
@@ -106,7 +106,7 @@ private static TabItemBlock CreateTabItem(
     private static Tuple<string, string, LinkInline> ParseHeading(HeadingBlock block)
     {
         var child = block.Inline.FirstChild;
-        if (child != null && child.NextSibling == null && child is LinkInline link)
+        if (child is {NextSibling: null} and LinkInline link)
         {
             var m = HrefRegex.Match(link.Url);
             if (m.Success)
diff --git a/src/Docfx.MarkdigEngine.Extensions/MonikerRange/MonikerRangeParser.cs b/src/Docfx.MarkdigEngine.Extensions/MonikerRange/MonikerRangeParser.cs
index 7a0f3e7e480..3e8a92f5756 100644
--- a/src/Docfx.MarkdigEngine.Extensions/MonikerRange/MonikerRangeParser.cs
+++ b/src/Docfx.MarkdigEngine.Extensions/MonikerRange/MonikerRangeParser.cs
@@ -142,7 +142,7 @@ public override BlockState TryContinue(BlockProcessor processor, Block block)
     public override bool Close(BlockProcessor processor, Block block)
     {
         var monikerRange = (MonikerRangeBlock)block;
-        if (monikerRange != null && monikerRange.Closed == false)
+        if (monikerRange is {Closed: false})
         {
             _context.LogWarning("invalid-moniker-range", $"No \"::: {EndString}\" found for \"{monikerRange.MonikerRange}\", MonikerRange does not end explicitly.", block);
         }
diff --git a/src/Docfx.MarkdigEngine.Extensions/PlantUml/PlantUmlCodeBlockRenderer.cs b/src/Docfx.MarkdigEngine.Extensions/PlantUml/PlantUmlCodeBlockRenderer.cs
index 776df0e678b..5957c059df4 100644
--- a/src/Docfx.MarkdigEngine.Extensions/PlantUml/PlantUmlCodeBlockRenderer.cs
+++ b/src/Docfx.MarkdigEngine.Extensions/PlantUml/PlantUmlCodeBlockRenderer.cs
@@ -44,9 +44,8 @@ public PlantUmlCodeBlockRenderer(MarkdownContext context, PlantUmlOptions settin
 
     protected override void Write(HtmlRenderer renderer, CodeBlock obj)
     {
-        if (obj is FencedCodeBlock fencedCodeBlock
-          && fencedCodeBlock.Info is string info
-          && info.Equals("plantuml", StringComparison.OrdinalIgnoreCase))
+        if (obj is FencedCodeBlock {Info: string info} fencedCodeBlock
+            && info.Equals("plantuml", StringComparison.OrdinalIgnoreCase))
         {
             IPlantUmlRenderer plantUmlRenderer = rendererFactory.CreateRenderer(_settings);
 
diff --git a/src/Docfx.MarkdigEngine.Extensions/ResolveLink/ResolveLinkExtension.cs b/src/Docfx.MarkdigEngine.Extensions/ResolveLink/ResolveLinkExtension.cs
index 2d7a45322b3..321d577d9ad 100644
--- a/src/Docfx.MarkdigEngine.Extensions/ResolveLink/ResolveLinkExtension.cs
+++ b/src/Docfx.MarkdigEngine.Extensions/ResolveLink/ResolveLinkExtension.cs
@@ -49,7 +49,7 @@ private void UpdateLinks(MarkdownObject markdownObject)
                 }
                 break;
 
-            case LeafBlock leafBlock when leafBlock.Inline != null:
+            case LeafBlock {Inline: not null} leafBlock:
                 foreach (var subInline in leafBlock.Inline)
                 {
                     UpdateLinks(subInline);
diff --git a/src/Docfx.MarkdigEngine.Extensions/Rewriter/MarkdownDocumentVisitor.cs b/src/Docfx.MarkdigEngine.Extensions/Rewriter/MarkdownDocumentVisitor.cs
index 04fd32e116d..fa3e396666e 100644
--- a/src/Docfx.MarkdigEngine.Extensions/Rewriter/MarkdownDocumentVisitor.cs
+++ b/src/Docfx.MarkdigEngine.Extensions/Rewriter/MarkdownDocumentVisitor.cs
@@ -43,7 +43,7 @@ private void RewriteContainerBlock(ContainerBlock blocks)
         for (var i = 0; i < blocks.Count; i++)
         {
             var block = blocks[i];
-            if (block is LeafBlock leafBlock && leafBlock.Inline != null)
+            if (block is LeafBlock {Inline: not null} leafBlock)
             {
                 RewriteContainerInline(leafBlock.Inline);
             }
diff --git a/src/Docfx.MarkdigEngine/MarkdigMarkdownService.cs b/src/Docfx.MarkdigEngine/MarkdigMarkdownService.cs
index 46d7f5c6ebf..dcfeb4e0c57 100644
--- a/src/Docfx.MarkdigEngine/MarkdigMarkdownService.cs
+++ b/src/Docfx.MarkdigEngine/MarkdigMarkdownService.cs
@@ -141,7 +141,7 @@ private MarkdownPipeline CreateMarkdownPipeline(bool isInline, bool multipleYaml
             builder.UseInlineOnly();
         }
 
-        if (_parameters?.Extensions?.MarkdigExtensions is { } extensions && extensions.Length > 0)
+        if (_parameters?.Extensions?.MarkdigExtensions is {Length: > 0} extensions)
         {
             builder.UseOptionalExtensions(extensions);
         }
diff --git a/src/Docfx.YamlSerialization/NodeTypeResolvers/ScalarYamlNodeTypeResolver.cs b/src/Docfx.YamlSerialization/NodeTypeResolvers/ScalarYamlNodeTypeResolver.cs
index b1e3f9c9ece..bca576600d1 100644
--- a/src/Docfx.YamlSerialization/NodeTypeResolvers/ScalarYamlNodeTypeResolver.cs
+++ b/src/Docfx.YamlSerialization/NodeTypeResolvers/ScalarYamlNodeTypeResolver.cs
@@ -13,7 +13,7 @@ bool INodeTypeResolver.Resolve(NodeEvent nodeEvent, ref Type currentType)
     {
         if (currentType == typeof(string) || currentType == typeof(object))
         {
-            if (nodeEvent is Scalar scalar && scalar.IsPlainImplicit)
+            if (nodeEvent is Scalar {IsPlainImplicit: true} scalar)
             {
                 if (Regexes.BooleanLike.IsMatch(scalar.Value))
                 {
diff --git a/src/Docfx.YamlSerialization/ObjectFactories/DefaultEmitObjectFactory.cs b/src/Docfx.YamlSerialization/ObjectFactories/DefaultEmitObjectFactory.cs
index 0b6ab897df4..300a7cf9cbb 100644
--- a/src/Docfx.YamlSerialization/ObjectFactories/DefaultEmitObjectFactory.cs
+++ b/src/Docfx.YamlSerialization/ObjectFactories/DefaultEmitObjectFactory.cs
@@ -18,7 +18,7 @@ public override object Create(Type type)
         if (!_cache.TryGetValue(type, out Func<object> func))
         {
             var realType = type;
-            if (type.IsInterface && type.IsGenericType)
+            if (type is {IsInterface: true, IsGenericType: true})
             {
                 var def = type.GetGenericTypeDefinition();
                 var args = type.GetGenericArguments();