Fixed warnings on null assignments

Author: alinasmirnova

src/BenchmarkDotNet.Diagnostics.Windows/InliningDiagnoser.cs

@@ -13,7 +13,7 @@ public class InliningDiagnoser : JitDiagnoser<object>, IProfiler
 
         private readonly bool logFailuresOnly = true;
         private readonly bool filterByNamespace = true;
-        private readonly string[] allowedNamespaces = null;
+        private readonly string[]? allowedNamespaces = null;
         private string defaultNamespace;
 
         // ReSharper disable once EmptyConstructor parameterless ctor is mandatory for DiagnosersLoader.CreateDiagnoser

src/BenchmarkDotNet.Diagnostics.Windows/Tracing/NativeMemoryLogParser.cs

@@ -95,7 +95,7 @@ private IEnumerable<Metric> Parse(TraceLog traceLog)
             var heapParser = new HeapTraceProviderTraceEventParser(eventSource);
             // We index by heap address and then within the heap we remember the allocation stack
             var heaps = new Dictionary<Address, Dictionary<Address, long>>();
-            Dictionary<Address, long> lastHeapAllocs = null;
+            Dictionary<Address, long>? lastHeapAllocs = null;
 
             Address lastHeapHandle = 0;
 

src/BenchmarkDotNet.Disassembler.x64/SourceCodeProvider.cs

@@ -134,7 +134,7 @@ private static SourceLocation FindNearestLine(PdbFunction function, int ilOffset
                 return null;
 
             int distance = int.MaxValue;
-            SourceLocation nearest = null;
+            SourceLocation? nearest = null;
 
             foreach (PdbSequencePointCollection sequenceCollection in function.SequencePoints)
             {
@@ -183,7 +183,7 @@ private static PdbReader GetReaderForMethod(ClrMethod method)
             ClrModule module = method?.Type?.Module;
             PdbInfo info = module?.Pdb;
 
-            PdbReader reader = null;
+            PdbReader? reader = null;
             if (info != null)
             {
                 if (!s_pdbReaders.TryGetValue(info, out reader))

src/BenchmarkDotNet/Characteristics/Characteristic.cs

@@ -86,7 +86,7 @@ protected Characteristic(
 
         private object FallbackValue { get; }
 
-        public object this[CharacteristicObject obj]
+        public object? this[CharacteristicObject obj]
         {
             get { return obj.GetValue(this); }
             set { obj.SetValue(this, value); }

src/BenchmarkDotNet/Disassemblers/MonoDisassembler.cs

@@ -128,7 +128,7 @@ private static DisassemblyResult CreateErrorResult(IReadOnlyList<string?> input,
             //line example 2: 0000000000000000  subq    $0x28, %rsp
             private static readonly Regex InstructionRegex = new Regex(@"\s*(?<address>[0-9a-f]+)(\:\s+([0-9a-f]{2}\s+)+)?\s+(?<instruction>.*)\s*", RegexOptions.Compiled);
 
-            private static bool TryParseInstruction(string line, out MonoCode instruction)
+            private static bool TryParseInstruction(string line, out MonoCode? instruction)
             {
                 instruction = null;
                 var match = InstructionRegex.Match(line);

src/BenchmarkDotNet/Disassemblers/SourceCodeProvider.cs

@@ -150,7 +150,7 @@ private static ManagedSymbolModule GetReaderForMethod(ClrMethod method)
             ClrModule module = method?.Type?.Module;
             PdbInfo info = module?.Pdb;
 
-            ManagedSymbolModule reader = null;
+            ManagedSymbolModule? reader = null;
             if (info != null)
             {
                 if (!s_pdbReaders.TryGetValue(info, out reader))

src/BenchmarkDotNet/Engines/AnonymousPipesHost.cs

@@ -63,7 +63,7 @@ public void SendSignal(HostSignal hostSignal)
         public void ReportResults(RunResults runResults) => runResults.Print(outWriter);
 
         [PublicAPI] // called from generated code
-        public static bool TryGetFileHandles(string[] args, out string writeHandle, out string readHandle)
+        public static bool TryGetFileHandles(string[] args, out string? writeHandle, out string? readHandle)
         {
             for (int i = 0; i < args.Length; i++)
             {

src/BenchmarkDotNet/Engines/Consumer.cs

@@ -31,7 +31,7 @@ private static readonly HashSet<Type> SupportedTypes
         private double doubleHolder;
         private long longHolder;
         private ulong ulongHolder;
-        private volatile object objectHolder;
+        private volatile object? objectHolder;
         private volatile IntPtr ptrHolder;
         private volatile UIntPtr uptrHolder;
 #pragma warning restore IDE0052 // Remove unread private members
@@ -157,7 +157,7 @@ public void Consume<T>(in T value)
         internal static bool IsConsumable(Type type)
             => SupportedTypes.Contains(type) || type.GetTypeInfo().IsClass || type.GetTypeInfo().IsInterface;
 
-        internal static bool HasConsumableField(Type type, out FieldInfo consumableField)
+        internal static bool HasConsumableField(Type type, out FieldInfo? consumableField)
         {
             var typeInfo = type.GetTypeInfo();
 

src/BenchmarkDotNet/Environments/ProcessorBrandStringHelper.cs

@@ -94,7 +94,7 @@ private static string GetBrandStyledActualFrequency(Frequency? frequency)
         {
             var data = ResourceHelper.LoadResource("BenchmarkDotNet.Environments.microarchitectures.txt").Split('\r', '\n');
             var dictionary = new Dictionary<string, string>();
-            string currentMicroarchitecture = null;
+            string? currentMicroarchitecture = null;
             foreach (string line in data)
             {
                if (line.StartsWith("//") || string.IsNullOrWhiteSpace(line))

src/BenchmarkDotNet/Environments/Runtimes/CoreRuntime.cs

@@ -77,7 +77,7 @@ internal static CoreRuntime FromVersion(Version version)
             }
         }
 
-        internal static bool TryGetVersion(out Version version)
+        internal static bool TryGetVersion(out Version? version)
         {
             // we can't just use System.Runtime.InteropServices.RuntimeInformation.FrameworkDescription
             // because it can be null and it reports versions like 4.6.* for .NET Core 2.*
@@ -124,7 +124,7 @@ internal static bool TryGetVersion(out Version version)
         // sample input:
         // for dotnet run: C:\Program Files\dotnet\shared\Microsoft.NETCore.App\2.1.12\
         // for dotnet publish: C:\Users\adsitnik\source\repos\ConsoleApp25\ConsoleApp25\bin\Release\netcoreapp2.0\win-x64\publish\
-        internal static bool TryGetVersionFromRuntimeDirectory(string runtimeDirectory, out Version version)
+        internal static bool TryGetVersionFromRuntimeDirectory(string runtimeDirectory, out Version? version)
         {
             if (!string.IsNullOrEmpty(runtimeDirectory) && Version.TryParse(GetParsableVersionPart(new DirectoryInfo(runtimeDirectory).Name), out version))
             {
@@ -141,7 +141,7 @@ internal static bool TryGetVersionFromRuntimeDirectory(string runtimeDirectory,
         // 2.2: 4.6.27817.03 @BuiltBy: dlab14-DDVSOWINAGE101 @Branch: release/2.2 @SrcCode: https://github.com/dotnet/coreclr/tree/ce1d090d33b400a25620c0145046471495067cc7, Microsoft .NET Framework
         // 3.0: 3.0.0-preview8.19379.2+ac25be694a5385a6a1496db40de932df0689b742, Microsoft .NET Core
         // 5.0: 5.0.0-alpha1.19413.7+0ecefa44c9d66adb8a997d5778dc6c246ad393a7, Microsoft .NET Core
-        internal static bool TryGetVersionFromProductInfo(string productVersion, string productName, out Version version)
+        internal static bool TryGetVersionFromProductInfo(string productVersion, string productName, out Version? version)
         {
             if (!string.IsNullOrEmpty(productVersion) && !string.IsNullOrEmpty(productName))
             {
@@ -175,7 +175,7 @@ internal static bool TryGetVersionFromProductInfo(string productVersion, string
         // sample input:
         // .NETCoreApp,Version=v2.0
         // .NETCoreApp,Version=v2.1
-        internal static bool TryGetVersionFromFrameworkName(string frameworkName, out Version version)
+        internal static bool TryGetVersionFromFrameworkName(string frameworkName, out Version? version)
         {
             const string versionPrefix = ".NETCoreApp,Version=v";
             if (!string.IsNullOrEmpty(frameworkName) && frameworkName.StartsWith(versionPrefix))