diff --git a/Codist/Helpers/CodeAnalysisHelper.Document.cs b/Codist/Helpers/CodeAnalysisHelper.Document.cs
index 341a429a..16d0b0ad 100644
--- a/Codist/Helpers/CodeAnalysisHelper.Document.cs
+++ b/Codist/Helpers/CodeAnalysisHelper.Document.cs
@@ -13,21 +13,12 @@ public static Document GetDocument(this Workspace workspace, ITextBuffer textBuf
 			if (workspace == null) {
 				throw new ArgumentNullException(nameof(workspace));
 			}
-			var solution = workspace.CurrentSolution;
-			if (solution == null) {
-				throw new InvalidOperationException("solution is null");
-			}
 			if (textBuffer == null) {
 				throw new InvalidOperationException("textBuffer is null");
 			}
-			var textContainer = textBuffer.AsTextContainer();
-			if (textContainer == null) {
-				throw new InvalidOperationException("textContainer is null");
-			}
-			var docId = workspace.GetDocumentIdInCurrentContext(textContainer);
-			if (docId is null) {
-				throw new InvalidOperationException("docId is null");
-			}
+			var solution = workspace.CurrentSolution ?? throw new InvalidOperationException("solution is null");
+			var textContainer = textBuffer.AsTextContainer() ?? throw new InvalidOperationException("textContainer is null");
+			var docId = workspace.GetDocumentIdInCurrentContext(textContainer) ?? throw new InvalidOperationException("docId is null");
 			return solution.WithDocumentText(docId, textContainer.CurrentText, PreservationMode.PreserveIdentity).GetDocument(docId);
 		}
 		public static Document GetDocument(this ITextBuffer textBuffer) {
@@ -39,8 +30,8 @@ public static Document GetDocument(this Project project, string filePath) {
 
 		/// <summary>Gets all <see cref="Document"/>s from a given <see cref="Project"/> and referencing/referenced projects.</summary>
 		public static IEnumerable<Document> GetRelatedProjectDocuments(this Project project) {
-			foreach (var proj in GetRelatedProjects(project)) {
-				foreach (var doc in proj.Documents) {
+			foreach (var p in GetRelatedProjects(project)) {
+				foreach (var doc in p.Documents) {
 					yield return doc;
 				}
 			}
@@ -54,10 +45,10 @@ static HashSet<Project> GetRelatedProjects(Project project) {
 			var projects = new HashSet<Project>();
 			GetRelatedProjects(project, projects);
 			var id = project.Id;
-			foreach (var proj in project.Solution.Projects) {
-				if (projects.Contains(proj) == false
-					&& proj.AllProjectReferences.Any(p => p.ProjectId == id)) {
-					projects.Add(proj);
+			foreach (var p in project.Solution.Projects) {
+				if (projects.Contains(p) == false
+					&& p.AllProjectReferences.Any(i => i.ProjectId == id)) {
+					projects.Add(p);
 				}
 			}
 			return projects;
diff --git a/Codist/Helpers/CodeAnalysisHelper.Symbol.cs b/Codist/Helpers/CodeAnalysisHelper.Symbol.cs
index 0c5fcb4c..7b483c5f 100644
--- a/Codist/Helpers/CodeAnalysisHelper.Symbol.cs
+++ b/Codist/Helpers/CodeAnalysisHelper.Symbol.cs
@@ -1122,26 +1122,30 @@ public static IReadOnlyList<ISymbol> GetExplicitInterfaceImplementations(this IS
 
 		public static IMethodSymbol AsMethod(this ISymbol symbol) {
 			switch (symbol.Kind) {
-				case SymbolKind.Method: return symbol as IMethodSymbol;
+				case SymbolKind.Method: return (IMethodSymbol)symbol;
 				case SymbolKind.Event: return ((IEventSymbol)symbol).RaiseMethod;
 				case SymbolKind.NamedType:
-					var t = symbol as INamedTypeSymbol;
+					var t = (INamedTypeSymbol)symbol;
 					return t.TypeKind == TypeKind.Delegate ? t.DelegateInvokeMethod : null;
 				default: return null;
 			}
 		}
 
-		public static async Task<Project> GetProjectAsync(this ISymbol symbol, Solution solution, CancellationToken cancellationToken = default) {
+		public static Task<Project> GetProjectAsync(this ISymbol symbol, Solution solution, CancellationToken cancellationToken = default) {
 			var asm = symbol.ContainingAssembly;
-			if (asm != null) {
-				foreach (var item in solution.Projects) {
+			return asm == null
+				? Task.FromResult<Project>(null)
+				: GetProjectAsync(asm, solution, cancellationToken);
+
+			async Task<Project> GetProjectAsync(IAssemblySymbol a, Solution s, CancellationToken ct) {
+				foreach (var item in s.Projects) {
 					if (item.SupportsCompilation
-						&& (await item.GetCompilationAsync(cancellationToken).ConfigureAwait(false)).Assembly == asm) {
+						&& (await item.GetCompilationAsync(ct).ConfigureAwait(false)).Assembly == a) {
 						return item;
 					}
 				}
+				return null;
 			}
-			return null;
 		}
 		#endregion
 
@@ -1455,7 +1459,9 @@ int GetSymbolKindSortOrder(SymbolKind x) {
 
 		public static int CompareByFieldIntegerConst(ISymbol a, ISymbol b) {
 			IFieldSymbol fa = a as IFieldSymbol, fb = b as IFieldSymbol;
-			return fa == null ? -1 : fb == null ? 1 : Convert.ToInt64(fa.ConstantValue).CompareTo(Convert.ToInt64(fb.ConstantValue));
+			return fa == null ? -1
+				: fb == null ? 1
+				: Convert.ToInt64(fa.ConstantValue).CompareTo(Convert.ToInt64(fb.ConstantValue));
 		}
 
 		public static bool IsBoundedGenericType(this INamedTypeSymbol type) {
@@ -1512,13 +1518,8 @@ public static bool MatchSignature(this ISymbol symbol, SymbolKind kind, ITypeSym
 					}
 				}
 			}
-			if (typeParameters.IsDefault == false) {
-				var typeParams = method.TypeParameters;
-				if (typeParams.Length != typeParameters.Length) {
-					return false;
-				}
-			}
-			return true;
+			return typeParameters.IsDefaultOrEmpty
+				|| method.TypeParameters.Length == typeParameters.Length;
 		}
 
 		/// <summary>Returns whether a symbol could have an override.</summary>
@@ -1625,7 +1626,7 @@ static Func<IAssemblySymbol, int> CreateAssemblySourceTypeFunc() {
 					il.Emit(OpCodes.Ldc_I4_2);
 					il.Emit(OpCodes.Ret);
 				}
-				return m.CreateDelegate(typeof(Func<IAssemblySymbol, int>)) as Func<IAssemblySymbol, int>;
+				return m.CreateDelegate<Func<IAssemblySymbol, int>>();
 			}
 		}
 
diff --git a/Codist/Helpers/CodeAnalysisHelper.cs b/Codist/Helpers/CodeAnalysisHelper.cs
index 30eb5082..3d8e197c 100644
--- a/Codist/Helpers/CodeAnalysisHelper.cs
+++ b/Codist/Helpers/CodeAnalysisHelper.cs
@@ -824,6 +824,7 @@ public static string GetDeclarationSignature(this SyntaxNode node, int position
 					return GetEndIfSignature((EndIfDirectiveTriviaSyntax)node);
 			}
 			return null;
+
 			string GetTypeSignature(TypeDeclarationSyntax syntax) => GetGenericSignature(syntax.Identifier.Text, syntax.Arity);
 			string GetMethodSignature(MethodDeclarationSyntax syntax) => GetGenericSignature(syntax.Identifier.Text, syntax.Arity);
 			string GetDelegateSignature(DelegateDeclarationSyntax syntax) => GetGenericSignature(syntax.Identifier.Text, syntax.Arity);
@@ -866,7 +867,7 @@ string GetGenericAritySignature(int arity) {
 					case 5: return "<,,,,>";
 					case 6: return "<,,,,,>";
 					case 7: return "<,,,,,,>";
-					default: return "<" + new String(',', arity - 1) + ">";
+					default: return "<" + new string(',', arity - 1) + ">";
 				}
 			}
 			string GetVariableSignature(VariableDeclarationSyntax syntax, int pos) {
@@ -1058,8 +1059,7 @@ public static SyntaxNode GetAncestorOrSelfDeclaration(this SyntaxNode node) {
 		/// <summary>Gets the first expression containing current node which is of type <typeparamref name="TExpression"/>.</summary>
 		public static TExpression GetAncestorOrSelfExpression<TExpression>(this SyntaxNode node)
 			where TExpression : ExpressionSyntax {
-			TExpression r;
-			if ((r = node as TExpression) != null) {
+			if (node is TExpression r) {
 				return r;
 			}
 			if (node is ExpressionSyntax) {
@@ -1074,14 +1074,13 @@ public static TExpression GetAncestorOrSelfExpression<TExpression>(this SyntaxNo
 		}
 		/// <summary>Gets the first node containing current node which is of type <typeparamref name="TSyntaxNode"/> and not <see cref="ExpressionSyntax"/>.</summary>
 		public static ExpressionSyntax GetLastAncestorExpressionNode(this SyntaxNode node) {
-			var r = node as ExpressionSyntax;
-			if (r == null) {
-				return null;
-			}
-			while (node.Parent is ExpressionSyntax n) {
-				node = r = n;
+			if (node is ExpressionSyntax r) {
+				while (node.Parent is ExpressionSyntax n) {
+					node = r = n;
+				}
+				return r;
 			}
-			return r;
+			return null;
 		}
 
 		public static IEnumerable<SyntaxNode> GetDescendantDeclarations(this SyntaxNode root, CancellationToken cancellationToken = default) {
@@ -1400,26 +1399,10 @@ public static ParameterSyntax FindParameter(this BaseMethodDeclarationSyntax nod
 			return node?.ParameterList.Parameters.FirstOrDefault(p => p.Identifier.Text == name);
 		}
 		public static TypeParameterSyntax FindTypeParameter(this SyntaxNode node, string name) {
-			TypeParameterListSyntax tp;
-			var m = node as MethodDeclarationSyntax;
-			if (m != null && m.Arity > 0) {
-				tp = m.TypeParameterList;
-			}
-			else {
-				var t = node as TypeDeclarationSyntax;
-				if (t != null && t.Arity > 0) {
-					tp = t.TypeParameterList;
-				}
-				else {
-					var d = node as DelegateDeclarationSyntax;
-					if (d != null && d.Arity > 0) {
-						tp = d.TypeParameterList;
-					}
-					else {
-						tp = null;
-					}
-				}
-			}
+			var tp = (node is MethodDeclarationSyntax m && m.Arity > 0) ? m.TypeParameterList
+				: node is TypeDeclarationSyntax t && t.Arity > 0 ? t.TypeParameterList
+				: node is DelegateDeclarationSyntax d && d.Arity > 0 ? d.TypeParameterList
+				: null;
 			return tp?.Parameters.FirstOrDefault(p => p.Identifier.Text == name);
 		}
 		public static bool IsLineComment(this SyntaxTrivia trivia) {
@@ -1481,7 +1464,9 @@ public static int GetWarningLevel(int csErrorCode) {
 		static partial class NonPublicOrFutureAccessors
 		{
 			public static readonly Func<SyntaxNode, NameSyntax> GetFileScopedNamespaceName = ReflectionHelper.CreateGetPropertyMethod<SyntaxNode, NameSyntax>("Name", typeof(NamespaceDeclarationSyntax).Assembly.GetType("Microsoft.CodeAnalysis.CSharp.Syntax.FileScopedNamespaceDeclarationSyntax"));
+
 			public static readonly Func<ExpressionSyntax, ArgumentListSyntax> GetImplicitObjectCreationArgumentList = ReflectionHelper.CreateGetPropertyMethod<ExpressionSyntax, ArgumentListSyntax>("ArgumentList", typeof(ExpressionSyntax).Assembly.GetType("Microsoft.CodeAnalysis.CSharp.Syntax.BaseObjectCreationExpressionSyntax"));
+
 			public static readonly Func<int, int> GetWarningLevel = ReflectionHelper.CallStaticFunc<int, int>(typeof(LanguageVersionFacts).Assembly.GetType("Microsoft.CodeAnalysis.CSharp.ErrorFacts")?.GetMethod("GetWarningLevel", BindingFlags.Static | BindingFlags.Public | BindingFlags.NonPublic)) ?? (Func<int, int>)((int _) => 3);
 		}
 	}
diff --git a/Codist/Helpers/VsShellHelper.cs b/Codist/Helpers/VsShellHelper.cs
index aa63f703..fc2f4e87 100644
--- a/Codist/Helpers/VsShellHelper.cs
+++ b/Codist/Helpers/VsShellHelper.cs
@@ -109,9 +109,10 @@ public static EnvDTE.Project GetProject(string projectName) {
 
 			EnvDTE.Project FindProject(EnvDTE.ProjectItems items, string pp) {
 				for (int i = 1; i <= items.Count; i++) {
-					var p = items.Item(i);
-					if (p.Object is EnvDTE.Project proj && String.Equals(proj.FullName, pp, StringComparison.OrdinalIgnoreCase)) {
-						return proj;
+					var item = items.Item(i);
+					if (item.Object is EnvDTE.Project p
+						&& String.Equals(p.FullName, pp, StringComparison.OrdinalIgnoreCase)) {
+						return p;
 					}
 				}
 				return null;
diff --git a/Codist/Margins/MarginFactories.cs b/Codist/Margins/MarginFactories.cs
index fcd9a67f..b11eb0c3 100644
--- a/Codist/Margins/MarginFactories.cs
+++ b/Codist/Margins/MarginFactories.cs
@@ -73,7 +73,10 @@ public IWpfTextViewMargin CreateMargin(IWpfTextViewHost wpfTextViewHost, IWpfTex
 	sealed class DisableChangeTrackerMarginFactory : IWpfTextViewMarginProvider
 	{
 		public IWpfTextViewMargin CreateMargin(IWpfTextViewHost wpfTextViewHost, IWpfTextViewMargin marginContainer) {
-			return CodistPackage.VsVersion.Major >= 17 && wpfTextViewHost.TextView.TextBuffer.MayBeEditor() ? new DisableChangeTrackerMargin(marginContainer) : null;
+			return CodistPackage.VsVersion.Major >= 17
+				&& wpfTextViewHost.TextView.TextBuffer.MayBeEditor()
+				? new DisableChangeTrackerMargin(marginContainer)
+				: null;
 		}
 	}
 
diff --git a/Codist/Margins/MarkerStyle.cs b/Codist/Margins/MarkerStyle.cs
index 0c1ea1dd..63a7b3ac 100644
--- a/Codist/Margins/MarkerStyle.cs
+++ b/Codist/Margins/MarkerStyle.cs
@@ -10,19 +10,23 @@ public sealed class MarkerStyle
 		Color _ForeColor, _BackColor;
 
 		public int Id { get => (int)StyleID; set => StyleID = (MarkerStyleTypes)value; }
+
 		internal MarkerStyleTypes StyleID { get; set; }
+
 		/// <summary>Gets or sets the foreground color to render the marker. The color format could be #RRGGBBAA or #RRGGBB.</summary>
 		[DefaultValue(Constants.EmptyColor)]
 		public string ForegroundColor {
 			get => ForeColor.ToHexString();
 			set => UIHelper.ParseColor(value, out _ForeColor, out _);
 		}
+
 		/// <summary>Gets or sets the foreground color to render the marker. The color format could be #RRGGBBAA or #RRGGBB.</summary>
 		[DefaultValue(Constants.EmptyColor)]
 		public string BackgroundColor {
 			get => BackColor.ToHexString();
 			set => UIHelper.ParseColor(value, out _BackColor, out _);
 		}
+
 		internal Color ForeColor { get => _ForeColor; set => _ForeColor = value; }
 		internal Color BackColor { get => _BackColor; set => _BackColor = value; }