Fix warnings and apply suggestions.

.vscode/tasks.json

@@ -11,7 +11,7 @@
         "/property:GenerateFullPaths=true",
         "/consoleloggerparameters:NoSummary"
       ],
-      "problemMatcher": "$msCompile"
+      "problemMatcher": []
     },
     {
       "label": "publish",
@@ -25,7 +25,7 @@
         "/property:GenerateFullPaths=true",
         "/consoleloggerparameters:NoSummary"
       ],
-      "problemMatcher": "$msCompile"
+      "problemMatcher": []
     },
     {
       "label": "watch",
@@ -38,7 +38,7 @@
         "/property:GenerateFullPaths=true",
         "/consoleloggerparameters:NoSummary"
       ],
-      "problemMatcher": "$msCompile"
+      "problemMatcher": []
     }
   ]
 }

perf/Utilities/MSBuildRegister.cs

@@ -8,7 +8,7 @@ namespace Microsoft.CodeAnalysis.Tools.Perf
 {
     public static class MSBuildRegister
     {
-        private static int s_registered = 0;
+        private static int s_registered;
 
         public static void RegisterInstance()
         {

perf/Utilities/SolutionPathSetter.cs

@@ -8,7 +8,7 @@ namespace Microsoft.CodeAnalysis.Tools.Perf
 {
     public static class SolutionPathSetter
     {
-        private static int s_registered = 0;
+        private static int s_registered;
         private static string s_currentDirectory;
         public static string RepositoryRootDirectory => Directory.GetParent(Environment.CurrentDirectory).Parent.Parent.Parent.Parent.Parent.Parent.Parent.Parent.FullName;
 

src/Analyzers/AnalyzerFormatter.cs

@@ -101,7 +101,7 @@ internal class AnalyzerFormatter : ICodeFormatter
             foreach (var project in solution.Projects)
             {
                 var analyzers = projectAnalyzers[project];
-                if (analyzers.Length == 0)
+                if (analyzers.IsEmpty)
                 {
                     continue;
                 }
@@ -116,13 +116,18 @@ internal class AnalyzerFormatter : ICodeFormatter
 
             static void LogDiagnosticLocations(Solution solution, IEnumerable<Diagnostic> diagnostics, string workspacePath, bool changesAreErrors, ILogger logger, List<FormattedFile> formattedFiles)
             {
-                var workspaceFolder = Path.GetDirectoryName(workspacePath);
+                var workspaceFolder = Path.GetDirectoryName(workspacePath) ?? workspacePath;
 
                 foreach (var diagnostic in diagnostics)
                 {
                     var message = $"{diagnostic.GetMessage()} ({diagnostic.Id})";
-                    var filePath = diagnostic.Location.SourceTree?.FilePath;
                     var document = solution.GetDocument(diagnostic.Location.SourceTree);
+                    if (document is null)
+                    {
+                        continue;
+                    }
+
+                    var filePath = document.FilePath ?? document.Name;
 
                     var mappedLineSpan = diagnostic.Location.GetMappedLineSpan();
                     var changePosition = mappedLineSpan.StartLinePosition;
@@ -252,7 +257,7 @@ static void LogDiagnosticLocations(Solution solution, IEnumerable<Diagnostic> di
                 {
                     // Always run naming style analyzers because we cannot determine potential severity.
                     // The reported diagnostics will be filtered by severity when they are run.
-                    if (analyzer.GetType().FullName.EndsWith("NamingStyleDiagnosticAnalyzer"))
+                    if (analyzer.GetType().FullName?.EndsWith("NamingStyleDiagnosticAnalyzer") == true)
                     {
                         analyzers.Add(analyzer);
                         continue;

src/Analyzers/AnalyzerReferenceInformationProvider.cs

@@ -70,7 +70,10 @@ internal class AnalyzerReferenceInformationProvider : IAnalyzerInformationProvid
             {
                 // Next see if this assembly has already been loaded into our context.
                 var assemblyName = AssemblyLoadContext.GetAssemblyName(path);
-                return AssemblyLoadContext.Default.LoadFromAssemblyName(new AssemblyName(assemblyName.Name));
+                if (assemblyName?.Name != null)
+                {
+                    return AssemblyLoadContext.Default.LoadFromAssemblyName(new AssemblyName(assemblyName.Name));
+                }
             }
             catch { }
 

src/Analyzers/CodeStyleInformationProvider.cs

@@ -12,7 +12,7 @@ namespace Microsoft.CodeAnalysis.Tools.Analyzers
 {
     internal class CodeStyleInformationProvider : IAnalyzerInformationProvider
     {
-        private static readonly string s_executingPath = Path.GetDirectoryName(Assembly.GetExecutingAssembly().Location);
+        private static readonly string s_executingPath = Path.GetDirectoryName(Assembly.GetExecutingAssembly().Location) ?? string.Empty;
 
         private readonly string _featuresPath = Path.Combine(s_executingPath, "Microsoft.CodeAnalysis.Features.dll");
         private readonly string _featuresCSharpPath = Path.Combine(s_executingPath, "Microsoft.CodeAnalysis.CSharp.Features.dll");

src/Analyzers/Extensions.cs

@@ -22,8 +22,8 @@ public static class Extensions
         static Extensions()
         {
             MicrosoftCodeAnalysisFeaturesAssembly = Assembly.Load(new AssemblyName("Microsoft.CodeAnalysis.Features"));
-            IDEDiagnosticIdToOptionMappingHelperType = MicrosoftCodeAnalysisFeaturesAssembly.GetType("Microsoft.CodeAnalysis.Diagnostics.IDEDiagnosticIdToOptionMappingHelper");
-            TryGetMappedOptionsMethod = IDEDiagnosticIdToOptionMappingHelperType.GetMethod("TryGetMappedOptions", BindingFlags.Static | BindingFlags.Public);
+            IDEDiagnosticIdToOptionMappingHelperType = MicrosoftCodeAnalysisFeaturesAssembly.GetType("Microsoft.CodeAnalysis.Diagnostics.IDEDiagnosticIdToOptionMappingHelper")!;
+            TryGetMappedOptionsMethod = IDEDiagnosticIdToOptionMappingHelperType.GetMethod("TryGetMappedOptions", BindingFlags.Static | BindingFlags.Public)!;
         }
 
         public static bool Any(this SolutionChanges solutionChanges)
@@ -36,7 +36,7 @@ public static bool Any(this SolutionChanges solutionChanges)
                 var defaultCtor = type.GetConstructor(
                     BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance,
                     binder: null,
-                    new Type[] { },
+                    Array.Empty<Type>(),
                     modifiers: null);
 
                 instance = defaultCtor != null
@@ -45,7 +45,7 @@ public static bool Any(this SolutionChanges solutionChanges)
                         BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance,
                         binder: null,
                         args: null,
-                        culture: null)
+                        culture: null)!
                     : null;
 
                 return instance != null;
@@ -160,7 +160,7 @@ public static DiagnosticSeverity ToSeverity(this ReportDiagnostic reportDiagnost
                 severity = DiagnosticSeverity.Hidden;
 
                 var parameters = new object?[] { descriptor.Id, compilation.Language, null };
-                var result = (bool)TryGetMappedOptionsMethod.Invoke(null, parameters);
+                var result = (bool)(TryGetMappedOptionsMethod.Invoke(null, parameters) ?? false);
 
                 if (!result)
                 {
@@ -170,7 +170,7 @@ public static DiagnosticSeverity ToSeverity(this ReportDiagnostic reportDiagnost
                 var codeStyleOptions = (IEnumerable)parameters[2]!;
                 foreach (var codeStyleOptionObj in codeStyleOptions)
                 {
-                    var codeStyleOption = (IOption)codeStyleOptionObj;
+                    var codeStyleOption = (IOption)codeStyleOptionObj!;
                     var option = options.GetOption(new OptionKey(codeStyleOption, codeStyleOption.IsPerLanguage ? compilation.Language : null));
                     if (option is null)
                     {
@@ -184,9 +184,13 @@ public static DiagnosticSeverity ToSeverity(this ReportDiagnostic reportDiagnost
                     }
 
                     var notification = notificationProperty.GetValue(option);
-                    var reportDiagnostic = (ReportDiagnostic)notification.GetType().GetProperty("Severity").GetValue(notification);
-                    var codeStyleSeverity = ToSeverity(reportDiagnostic);
+                    var reportDiagnosticValue = notification?.GetType().GetProperty("Severity")?.GetValue(notification);
+                    if (reportDiagnosticValue is null)
+                    {
+                        continue;
+                    }
 
+                    var codeStyleSeverity = ToSeverity((ReportDiagnostic)reportDiagnosticValue);
                     if (codeStyleSeverity > severity)
                     {
                         severity = codeStyleSeverity;

src/Formatters/EndOfLineFormatter.cs

@@ -38,7 +38,7 @@ internal sealed class EndOfLineFormatter : DocumentFormatter
                     var lineEndingSpan = new TextSpan(line.End, line.EndIncludingLineBreak - line.End);
 
                     // Check for end of file
-                    if (lineEndingSpan.Length == 0)
+                    if (lineEndingSpan.IsEmpty)
                     {
                         break;
                     }

src/Formatters/FinalNewlineFormatter.cs

@@ -1,7 +1,6 @@
 // Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the MIT license.  See License.txt in the project root for license information.
 
 using System;
-using System.Linq;
 using System.Threading;
 using System.Threading.Tasks;
 using Microsoft.CodeAnalysis.Diagnostics;
@@ -35,7 +34,7 @@ internal sealed class FinalNewlineFormatter : DocumentFormatter
                 endOfLine = Environment.NewLine;
             }
 
-            var lastLine = sourceText.Lines.Last();
+            var lastLine = sourceText.Lines[^1];
             var hasFinalNewline = lastLine.Span.IsEmpty;
 
             if (insertFinalNewline && !hasFinalNewline)
@@ -49,12 +48,12 @@ internal sealed class FinalNewlineFormatter : DocumentFormatter
                 // In the case of empty files where there is a single empty line, there is nothing to remove.
                 while (sourceText.Lines.Count > 1 && hasFinalNewline)
                 {
-                    var lineBeforeLast = sourceText.Lines[sourceText.Lines.Count - 2];
+                    var lineBeforeLast = sourceText.Lines[^2];
                     var finalNewlineSpan = new TextSpan(lineBeforeLast.End, lineBeforeLast.EndIncludingLineBreak - lineBeforeLast.End);
                     var removeNewlineChange = new TextChange(finalNewlineSpan, string.Empty);
                     sourceText = sourceText.WithChanges(removeNewlineChange);
 
-                    lastLine = sourceText.Lines.Last();
+                    lastLine = sourceText.Lines[^1];
                     hasFinalNewline = lastLine.Span.IsEmpty;
                 }
             }

src/Formatters/UnnecessaryImportsFormatter.cs

@@ -49,6 +49,10 @@ internal sealed class UnnecessaryImportsFormatter : DocumentFormatter
             }
 
             var formattedDocument = await RemoveUnnecessaryImportsHelper.RemoveUnnecessaryImportsAsync(document, cancellationToken).ConfigureAwait(false);
+            if (formattedDocument is null)
+            {
+                return sourceText;
+            }
 
             var isSameVersion = await IsSameDocumentAndVersionAsync(document, formattedDocument, cancellationToken).ConfigureAwait(false);
             if (isSameVersion)

src/MSBuild/LooseVersionAssemblyLoader.cs

@@ -69,10 +69,13 @@ public static void Register(string searchPath)
                     }
                     catch
                     {
-                        // We were unable to load the assembly from the file path. It is likely that
-                        // a different version of the assembly has already been loaded into the context.
-                        // Be forgiving and attempt to load assembly by name without specifying a version.
-                        return context.LoadFromAssemblyName(new AssemblyName(assemblyName.Name));
+                        if (assemblyName.Name != null)
+                        {
+                            // We were unable to load the assembly from the file path. It is likely that
+                            // a different version of the assembly has already been loaded into the context.
+                            // Be forgiving and attempt to load assembly by name without specifying a version.
+                            return context.LoadFromAssemblyName(new AssemblyName(assemblyName.Name));
+                        }
                     }
                 }
             }

src/Program.cs

@@ -29,7 +29,7 @@ internal class Program
         private static async Task<int> Main(string[] args)
         {
             var rootCommand = FormatCommand.CreateCommandLineOptions();
-            rootCommand.Handler = CommandHandler.Create(typeof(Program).GetMethod(nameof(Run)));
+            rootCommand.Handler = CommandHandler.Create(typeof(Program).GetMethod(nameof(Run))!);
 
             // Parse the incoming args so we can give warnings when deprecated options are used.
             s_parseResult = rootCommand.Parse(args);
@@ -74,7 +74,7 @@ private static async Task<int> Main(string[] args)
                 currentDirectory = Environment.CurrentDirectory;
 
 
-                string workspaceDirectory;
+                string? workspaceDirectory;
                 string workspacePath;
                 WorkspaceType workspaceType;
 

src/Reflection/RemoveUnnecessaryImportsHelper.cs

@@ -13,7 +13,7 @@ internal static class RemoveUnnecessaryImportsHelper
         private static readonly Type? s_abstractRemoveUnnecessaryImportsCodeFixProviderType = s_microsoftCodeAnalysisFeaturesAssembly?.GetType("Microsoft.CodeAnalysis.RemoveUnnecessaryImports.AbstractRemoveUnnecessaryImportsCodeFixProvider");
         private static readonly MethodInfo? s_removeUnnecessaryImportsAsyncMethod = s_abstractRemoveUnnecessaryImportsCodeFixProviderType?.GetMethod("RemoveUnnecessaryImportsAsync", BindingFlags.Static | BindingFlags.NonPublic);
 
-        public static async Task<Document> RemoveUnnecessaryImportsAsync(Document document, CancellationToken cancellationToken)
+        public static async Task<Document?> RemoveUnnecessaryImportsAsync(Document document, CancellationToken cancellationToken)
         {
             if (s_removeUnnecessaryImportsAsyncMethod is null)
             {

src/ReportWriter.cs

@@ -15,7 +15,7 @@ public static void Write(string reportPath, IEnumerable<FormattedFile> formatted
             var reportFilePath = GetReportFilePath(reportPath);
             var reportFolderPath = Path.GetDirectoryName(reportFilePath);
 
-            if (!Directory.Exists(reportFolderPath))
+            if (reportFolderPath != null && !Directory.Exists(reportFolderPath))
             {
                 Directory.CreateDirectory(reportFolderPath);
             }