Fix lint command (#3027)

Use new version of MicrosoftCodeAnalysisVersion in linker (Copy from runtime) to fix the dotnet format command
Run the dotnet format command
Reenable Lint check in ci pipelines

26 files changed, 102 insertions, 135 deletions

diff --git a/eng/Versions.props b/eng/Versions.props
index a0e4eed52..3c9f971c1 100644
--- a/eng/Versions.props
+++ b/eng/Versions.props
@@ -21,7 +21,7 @@
     <MicrosoftDotNetApiCompatVersion>7.0.0-beta.22426.8</MicrosoftDotNetApiCompatVersion>
     <MicrosoftDotNetCodeAnalysisVersion>6.0.0-beta.21271.1</MicrosoftDotNetCodeAnalysisVersion>
     <MicrosoftCodeAnalysisCSharpCodeStyleVersion>3.10.0-2.final</MicrosoftCodeAnalysisCSharpCodeStyleVersion>
-    <MicrosoftCodeAnalysisVersion>4.4.0-2.22379.3</MicrosoftCodeAnalysisVersion>
+    <MicrosoftCodeAnalysisVersion>4.4.0-1.final</MicrosoftCodeAnalysisVersion>
     <MicrosoftNetCompilersToolsetVersion>$(MicrosoftCodeAnalysisVersion)</MicrosoftNetCompilersToolsetVersion>
     <MicrosoftCodeAnalysisCSharpAnalyzerTestingXunitVersion>1.0.1-beta1.*</MicrosoftCodeAnalysisCSharpAnalyzerTestingXunitVersion>
     <MicrosoftCodeAnalysisBannedApiAnalyzersVersion>3.3.2</MicrosoftCodeAnalysisBannedApiAnalyzersVersion>
diff --git a/eng/azure-pipelines.yml b/eng/azure-pipelines.yml
index 35c0deff9..6c555ca49 100644
--- a/eng/azure-pipelines.yml
+++ b/eng/azure-pipelines.yml
@@ -145,9 +145,7 @@ stages:
       steps:
       - checkout: self
         submodules: true
-      # Disabled to prevent dotnet-format bugs (see https://github.com/dotnet/linker/pull/2884).
-      # This should be turned back on when we are on a preview7 SDK.
-      # - script: ./lint.sh --verify-no-changes --verbosity diagnostic
+      - script: ./lint.sh --verify-no-changes --verbosity diagnostic
 
 # Post-Build Arcade logic
 - ${{ if eq(variables.officialBuild, 'true') }}:
diff --git a/src/ILLink.CodeFix/RequiresAssemblyFilesCodeFixProvider.cs b/src/ILLink.CodeFix/RequiresAssemblyFilesCodeFixProvider.cs
index 7ed5a8414..f55258251 100644
--- a/src/ILLink.CodeFix/RequiresAssemblyFilesCodeFixProvider.cs
+++ b/src/ILLink.CodeFix/RequiresAssemblyFilesCodeFixProvider.cs
@@ -1,7 +1,6 @@
 // Copyright (c) .NET Foundation and contributors. All rights reserved.
 // Licensed under the MIT license. See LICENSE file in the project root for full license information.
 
-using System;
 using System.Collections.Immutable;
 using System.Composition;
 using System.Linq;
@@ -33,7 +32,7 @@ namespace ILLink.CodeFix
 
 		public sealed override Task RegisterCodeFixesAsync (CodeFixContext context) => BaseRegisterCodeFixesAsync (context);
 
-		protected override SyntaxNode[] GetAttributeArguments (ISymbol? attributableSymbol, ISymbol targetSymbol, SyntaxGenerator syntaxGenerator, Diagnostic diagnostic) => 
-			RequiresHelpers.GetAttributeArgumentsForRequires (targetSymbol, syntaxGenerator, HasPublicAccessibility(attributableSymbol));
+		protected override SyntaxNode[] GetAttributeArguments (ISymbol? attributableSymbol, ISymbol targetSymbol, SyntaxGenerator syntaxGenerator, Diagnostic diagnostic) =>
+			RequiresHelpers.GetAttributeArgumentsForRequires (targetSymbol, syntaxGenerator, HasPublicAccessibility (attributableSymbol));
 	}
 }
diff --git a/src/ILLink.CodeFix/RequiresDynamicCodeCodeFixProvider.cs b/src/ILLink.CodeFix/RequiresDynamicCodeCodeFixProvider.cs
index 807d14b7d..62c484d41 100644
--- a/src/ILLink.CodeFix/RequiresDynamicCodeCodeFixProvider.cs
+++ b/src/ILLink.CodeFix/RequiresDynamicCodeCodeFixProvider.cs
@@ -1,7 +1,6 @@
 // Copyright (c) .NET Foundation and contributors. All rights reserved.
 // Licensed under the MIT license. See LICENSE file in the project root for full license information.
 
-using System;
 using System.Collections.Immutable;
 using System.Composition;
 using System.Linq;
diff --git a/src/ILLink.CodeFix/RequiresHelpers.cs b/src/ILLink.CodeFix/RequiresHelpers.cs
index 91bb99591..b38f11ca4 100644
--- a/src/ILLink.CodeFix/RequiresHelpers.cs
+++ b/src/ILLink.CodeFix/RequiresHelpers.cs
@@ -2,9 +2,9 @@
 // Licensed under the MIT license. See LICENSE file in the project root for full license information.
 
 using System;
-using Microsoft.CodeAnalysis.Editing;
-using Microsoft.CodeAnalysis;
 using ILLink.RoslynAnalyzer;
+using Microsoft.CodeAnalysis;
+using Microsoft.CodeAnalysis.Editing;
 
 namespace ILLink.CodeFixProvider
 {
diff --git a/src/ILLink.CodeFix/RequiresUnreferencedCodeCodeFixProvider.cs b/src/ILLink.CodeFix/RequiresUnreferencedCodeCodeFixProvider.cs
index 5535e1764..4fe909683 100644
--- a/src/ILLink.CodeFix/RequiresUnreferencedCodeCodeFixProvider.cs
+++ b/src/ILLink.CodeFix/RequiresUnreferencedCodeCodeFixProvider.cs
@@ -1,7 +1,6 @@
 // Copyright (c) .NET Foundation and contributors. All rights reserved.
 // Licensed under the MIT license. See LICENSE file in the project root for full license information.
 
-using System;
 using System.Collections.Immutable;
 using System.Composition;
 using System.Linq;
diff --git a/src/ILLink.RoslynAnalyzer/CompilationExtensions.cs b/src/ILLink.RoslynAnalyzer/CompilationExtensions.cs
index 0f3d7f8e0..a2c4840fe 100644
--- a/src/ILLink.RoslynAnalyzer/CompilationExtensions.cs
+++ b/src/ILLink.RoslynAnalyzer/CompilationExtensions.cs
@@ -1,10 +1,10 @@
 // Copyright (c) .NET Foundation and contributors. All rights reserved.
 // Licensed under the MIT license. See LICENSE file in the project root for full license information.
 
+using System;
+using System.Collections.Immutable;
 using Microsoft.CodeAnalysis;
 using Microsoft.CodeAnalysis.CSharp.Syntax;
-using System.Collections.Immutable;
-using System;
 
 namespace ILLink.RoslynAnalyzer
 {
@@ -73,7 +73,7 @@ namespace ILLink.RoslynAnalyzer
 
 			return type;
 		}
-		
+
 		// copied from https://github.com/dotnet/roslyn/blob/main/src/Workspaces/SharedUtilitiesAndExtensions/Compiler/Core/Extensions/ISymbolExtensions.cs
 		private static SymbolVisibility GetResultantVisibility (this ISymbol symbol)
 		{
diff --git a/src/ILLink.Tasks/CreateRuntimeRootDescriptorFile.cs b/src/ILLink.Tasks/CreateRuntimeRootDescriptorFile.cs
index e95d2e505..5685f3cfd 100644
--- a/src/ILLink.Tasks/CreateRuntimeRootDescriptorFile.cs
+++ b/src/ILLink.Tasks/CreateRuntimeRootDescriptorFile.cs
@@ -423,9 +423,7 @@ namespace ILLink.Tasks
 				members = featureSwitchMembers[featureSwitch.Value][className];
 			}
 
-			if (members.fields == null) {
-				members.fields = new HashSet<string> ();
-			}
+			members.fields ??= new HashSet<string> ();
 			members.fields.Add (fieldName);
 		}
 
@@ -446,9 +444,7 @@ namespace ILLink.Tasks
 				members = featureSwitchMembers[featureSwitch.Value][fullClassName];
 			}
 
-			if (members.methods == null) {
-				members.methods = new HashSet<string> ();
-			}
+			members.methods ??= new HashSet<string> ();
 			members.methods.Add (methodName);
 		}
 
diff --git a/src/analyzer/LinkerAnalyzerCore/DependencyGraph.cs b/src/analyzer/LinkerAnalyzerCore/DependencyGraph.cs
index 275756b01..2b6c49063 100644
--- a/src/analyzer/LinkerAnalyzerCore/DependencyGraph.cs
+++ b/src/analyzer/LinkerAnalyzerCore/DependencyGraph.cs
@@ -70,8 +70,7 @@ namespace LinkerAnalyzer.Core
 								VertexData begin = Vertex (b, true);
 								VertexData end = Vertex (e, true);
 
-								if (end.parentIndexes == null)
-									end.parentIndexes = new List<int> ();
+								end.parentIndexes ??= new List<int> ();
 								if (!end.parentIndexes.Contains (begin.index)) {
 									end.parentIndexes.Add (begin.index);
 									//Console.WriteLine (" end parent index: {0}", end.parentIndexes);
diff --git a/src/linker/Linker.Dataflow/AttributeDataFlow.cs b/src/linker/Linker.Dataflow/AttributeDataFlow.cs
index 5dccfe2b1..03a32483c 100644
--- a/src/linker/Linker.Dataflow/AttributeDataFlow.cs
+++ b/src/linker/Linker.Dataflow/AttributeDataFlow.cs
@@ -28,7 +28,7 @@ namespace Mono.Linker.Dataflow
 		public void ProcessAttributeDataflow (MethodDefinition method, IList<CustomAttributeArgument> arguments)
 		{
 			for (int i = 0; i < method.Parameters.Count; i++) {
-				var parameterValue = _context.Annotations.FlowAnnotations.GetMethodParameterValue (method, (SourceParameterIndex)i);
+				var parameterValue = _context.Annotations.FlowAnnotations.GetMethodParameterValue (method, (SourceParameterIndex) i);
 				if (parameterValue.DynamicallyAccessedMemberTypes != DynamicallyAccessedMemberTypes.None) {
 					MultiValue value = GetValueForCustomAttributeArgument (arguments[i]);
 					var diagnosticContext = new DiagnosticContext (_origin, diagnosticsEnabled: true, _context);
diff --git a/src/linker/Linker.Dataflow/FlowAnnotations.cs b/src/linker/Linker.Dataflow/FlowAnnotations.cs
index e7ed760df..f0c8cce9a 100644
--- a/src/linker/Linker.Dataflow/FlowAnnotations.cs
+++ b/src/linker/Linker.Dataflow/FlowAnnotations.cs
@@ -276,9 +276,7 @@ namespace ILLink.Shared.TrimAnalysis
 							continue;
 						}
 
-						if (paramAnnotations == null) {
-							paramAnnotations = new DynamicallyAccessedMemberTypes[method.Parameters.Count + offset];
-						}
+						paramAnnotations ??= new DynamicallyAccessedMemberTypes[method.Parameters.Count + offset];
 						paramAnnotations[i + offset] = pa;
 					}
 
@@ -293,8 +291,7 @@ namespace ILLink.Shared.TrimAnalysis
 							var genericParameter = method.GenericParameters[genericParameterIndex];
 							var annotation = GetMemberTypesForDynamicallyAccessedMembersAttribute (method, providerIfNotMember: genericParameter);
 							if (annotation != DynamicallyAccessedMemberTypes.None) {
-								if (genericParameterAnnotations == null)
-									genericParameterAnnotations = new DynamicallyAccessedMemberTypes[method.GenericParameters.Count];
+								genericParameterAnnotations ??= new DynamicallyAccessedMemberTypes[method.GenericParameters.Count];
 								genericParameterAnnotations[genericParameterIndex] = annotation;
 							}
 						}
@@ -406,8 +403,7 @@ namespace ILLink.Shared.TrimAnalysis
 					var provider = attrs?[genericParameterIndex] ?? type.GenericParameters[genericParameterIndex];
 					var annotation = GetMemberTypesForDynamicallyAccessedMembersAttribute (type, providerIfNotMember: provider);
 					if (annotation != DynamicallyAccessedMemberTypes.None) {
-						if (typeGenericParameterAnnotations == null)
-							typeGenericParameterAnnotations = new DynamicallyAccessedMemberTypes[type.GenericParameters.Count];
+						typeGenericParameterAnnotations ??= new DynamicallyAccessedMemberTypes[type.GenericParameters.Count];
 						typeGenericParameterAnnotations[genericParameterIndex] = annotation;
 					}
 				}
diff --git a/src/linker/Linker.Dataflow/MethodBodyScanner.cs b/src/linker/Linker.Dataflow/MethodBodyScanner.cs
index 179ac10bb..0216252cc 100644
--- a/src/linker/Linker.Dataflow/MethodBodyScanner.cs
+++ b/src/linker/Linker.Dataflow/MethodBodyScanner.cs
@@ -12,11 +12,11 @@ using ILLink.Shared.TypeSystemProxy;
 using Mono.Cecil;
 using Mono.Cecil.Cil;
 using Mono.Collections.Generic;
+using static Mono.Linker.ParameterHelpers;
 using LocalVariableStore = System.Collections.Generic.Dictionary<
 	Mono.Cecil.Cil.VariableDefinition,
 	Mono.Linker.Dataflow.ValueBasicBlockPair>;
 using MultiValue = ILLink.Shared.DataFlow.ValueSet<ILLink.Shared.DataFlow.SingleValue>;
-using static Mono.Linker.ParameterHelpers;
 
 namespace Mono.Linker.Dataflow
 {
@@ -301,9 +301,7 @@ namespace Mono.Linker.Dataflow
 					}
 				}
 
-				if (currentStack == null) {
-					currentStack = new Stack<StackSlot> (methodBody.MaxStackSize);
-				}
+				currentStack ??= new Stack<StackSlot> (methodBody.MaxStackSize);
 
 				switch (operation.OpCode.Code) {
 				case Code.Add:
@@ -1097,7 +1095,7 @@ namespace Mono.Linker.Dataflow
 
 				if (calledMethod.ParameterReferenceKind ((int) ilArgumentIndex) is not (ReferenceKind.Ref or ReferenceKind.Out))
 					continue;
-				SingleValue newByRefValue = methodIsResolved && (int)parameterIndex < calledMethodDefinition!.Parameters.Count
+				SingleValue newByRefValue = methodIsResolved && (int) parameterIndex < calledMethodDefinition!.Parameters.Count
 					? _context.Annotations.FlowAnnotations.GetMethodParameterValue (calledMethodDefinition!, parameterIndex)
 					: UnknownValue.Instance;
 				StoreInReference (methodArguments[(int) ilArgumentIndex], newByRefValue, callingMethodBody.Method, operation, locals, curBasicBlock, ref ipState);
diff --git a/src/linker/Linker.Steps/DiscoverCustomOperatorsHandler.cs b/src/linker/Linker.Steps/DiscoverCustomOperatorsHandler.cs
index 24e324590..5811555c6 100644
--- a/src/linker/Linker.Steps/DiscoverCustomOperatorsHandler.cs
+++ b/src/linker/Linker.Steps/DiscoverCustomOperatorsHandler.cs
@@ -24,8 +24,7 @@ namespace Mono.Linker.Steps
 
 		Dictionary<TypeDefinition, List<MethodDefinition>> PendingOperatorsForType {
 			get {
-				if (_pendingOperatorsForType == null)
-					_pendingOperatorsForType = new Dictionary<TypeDefinition, List<MethodDefinition>> ();
+				_pendingOperatorsForType ??= new Dictionary<TypeDefinition, List<MethodDefinition>> ();
 				return _pendingOperatorsForType;
 			}
 		}
@@ -119,8 +118,7 @@ namespace Mono.Linker.Steps
 		TypeDefinition? _nullableOfT;
 		TypeDefinition? NullableOfT {
 			get {
-				if (_nullableOfT == null)
-					_nullableOfT = BCL.FindPredefinedType (WellKnownType.System_Nullable_T, Context);
+				_nullableOfT ??= BCL.FindPredefinedType (WellKnownType.System_Nullable_T, Context);
 				return _nullableOfT;
 			}
 		}
diff --git a/src/linker/Linker.Steps/UnreachableBlocksOptimizer.cs b/src/linker/Linker.Steps/UnreachableBlocksOptimizer.cs
index d91fb09dd..d6bc01798 100644
--- a/src/linker/Linker.Steps/UnreachableBlocksOptimizer.cs
+++ b/src/linker/Linker.Steps/UnreachableBlocksOptimizer.cs
@@ -319,8 +319,7 @@ namespace Mono.Linker.Steps
 				if (!IsConstantValue (instr))
 					return null;
 
-				if (result == null)
-					result = new Instruction[method.Parameters.Count];
+				result ??= new Instruction[method.Parameters.Count];
 
 				result[pos] = instr;
 			}
@@ -578,8 +577,7 @@ namespace Mono.Linker.Steps
 
 			void RewriteConditionToNop (int index)
 			{
-				if (conditionInstrsToRemove == null)
-					conditionInstrsToRemove = new List<int> ();
+				conditionInstrsToRemove ??= new List<int> ();
 
 				conditionInstrsToRemove.Add (index);
 				RewriteToNop (index);
@@ -755,8 +753,7 @@ namespace Mono.Linker.Steps
 						Instruction[]? args = GetArgumentsOnStack (md, FoldedInstructions ?? instructions, i);
 						targetResult = args?.Length > 0 && md.IsStatic ? EvaluateIntrinsicCall (md, args) : null;
 
-						if (targetResult == null)
-							targetResult = optimizer.TryGetMethodCallResult (new CalleePayload (md, args))?.Instruction;
+						targetResult ??= optimizer.TryGetMethodCallResult (new CalleePayload (md, args))?.Instruction;
 
 						if (targetResult == null)
 							break;
@@ -1007,8 +1004,7 @@ namespace Mono.Linker.Steps
 							continue;
 
 						case FlowControl.Cond_Branch:
-							if (condBranches == null)
-								condBranches = new Stack<int> ();
+							condBranches ??= new Stack<int> ();
 
 							switch (instr.Operand) {
 							case Instruction starget:
@@ -1052,15 +1048,13 @@ namespace Mono.Linker.Steps
 							int end = instrs.IndexOf (handler.TryEnd) - 1;
 
 							if (!HasAnyBitSet (reachable, start, end)) {
-								if (unreachableHandlers == null)
-									unreachableHandlers = new List<ExceptionHandler> ();
+								unreachableHandlers ??= new List<ExceptionHandler> ();
 
 								unreachableHandlers.Add (handler);
 								continue;
 							}
 
-							if (condBranches == null)
-								condBranches = new Stack<int> ();
+							condBranches ??= new Stack<int> ();
 
 							condBranches.Push (GetInstructionIndex (handler.HandlerStart));
 							if (handler.FilterStart != null)
@@ -1240,8 +1234,7 @@ namespace Mono.Linker.Steps
 
 					VariableDefinition? variable = GetVariableReference (instr);
 					if (variable != null) {
-						if (removedVariablesReferences == null)
-							removedVariablesReferences = new List<VariableDefinition> ();
+						removedVariablesReferences ??= new List<VariableDefinition> ();
 						if (!removedVariablesReferences.Contains (variable))
 							removedVariablesReferences.Add (variable);
 					}
@@ -1273,8 +1266,7 @@ namespace Mono.Linker.Steps
 							if (index > 0 && IsSideEffectFreeLoad (instrs[index - 1])) {
 								var nop = Instruction.Create (OpCodes.Nop);
 
-								if (sentinelNops == null)
-									sentinelNops = new List<Instruction> ();
+								sentinelNops ??= new List<Instruction> ();
 								sentinelNops.Add (nop);
 
 								ILProcessor.Replace (index - 1, Instruction.Create (OpCodes.Pop));
@@ -1902,16 +1894,14 @@ namespace Mono.Linker.Steps
 
 			void PushOnStack (Instruction instruction)
 			{
-				if (stack_instr == null)
-					stack_instr = new Stack<Instruction> ();
+				stack_instr ??= new Stack<Instruction> ();
 
 				stack_instr.Push (instruction);
 			}
 
 			void StoreToLocals (int index)
 			{
-				if (locals == null)
-					locals = new Dictionary<int, Instruction> ();
+				locals ??= new Dictionary<int, Instruction> ();
 
 				if (stack_instr == null)
 					Debug.Fail ("Invalid IL?");
diff --git a/src/linker/Linker/AssemblyResolver.cs b/src/linker/Linker/AssemblyResolver.cs
index 87b8b74d6..b833a504c 100644
--- a/src/linker/Linker/AssemblyResolver.cs
+++ b/src/linker/Linker/AssemblyResolver.cs
@@ -100,12 +100,10 @@ namespace Mono.Linker
 			// Any full path explicit reference takes precedence over other look up logic
 			asm = ResolveFromReferences (name);
 
-			if (asm == null)
-				asm = SearchDirectory (name);
+			asm ??= SearchDirectory (name);
 
 			if (asm == null) {
-				if (_unresolvedAssemblies == null)
-					_unresolvedAssemblies = new HashSet<string> ();
+				_unresolvedAssemblies ??= new HashSet<string> ();
 
 				if (!probing)
 					ReportUnresolvedAssembly (name);
@@ -120,8 +118,7 @@ namespace Mono.Linker
 
 		void ReportUnresolvedAssembly (AssemblyNameReference reference)
 		{
-			if (_reportedUnresolvedAssemblies == null)
-				_reportedUnresolvedAssemblies = new HashSet<string> ();
+			_reportedUnresolvedAssemblies ??= new HashSet<string> ();
 
 			if (!_reportedUnresolvedAssemblies.Add (reference.Name))
 				return;
diff --git a/src/linker/Linker/DgmlDependencyRecorder.cs b/src/linker/Linker/DgmlDependencyRecorder.cs
index 5cf4dc832..0bccf909b 100644
--- a/src/linker/Linker/DgmlDependencyRecorder.cs
+++ b/src/linker/Linker/DgmlDependencyRecorder.cs
@@ -31,8 +31,7 @@ namespace Mono.Linker
 				IndentChars = " "
 			};
 
-			if (fileName == null)
-				fileName = DefaultDependenciesFileName;
+			fileName ??= DefaultDependenciesFileName;
 
 			if (string.IsNullOrEmpty (Path.GetDirectoryName (fileName)) && !string.IsNullOrEmpty (context.OutputDirectory)) {
 				fileName = Path.Combine (context.OutputDirectory, fileName);
diff --git a/src/linker/Linker/LinkerAttributesInformation.cs b/src/linker/Linker/LinkerAttributesInformation.cs
index 27fbcdac1..9fef9b59c 100644
--- a/src/linker/Linker/LinkerAttributesInformation.cs
+++ b/src/linker/Linker/LinkerAttributesInformation.cs
@@ -69,8 +69,7 @@ namespace Mono.Linker
 				if (attributeValue == null)
 					continue;
 
-				if (cache == null)
-					cache = new List<(Type Type, List<Attribute> Attributes)> ();
+				cache ??= new List<(Type Type, List<Attribute> Attributes)> ();
 
 				Type attributeValueType = attributeValue.GetType ();
 
diff --git a/src/linker/Linker/ParameterHelpers.cs b/src/linker/Linker/ParameterHelpers.cs
index 2ea4786b1..eeca9c28c 100644
--- a/src/linker/Linker/ParameterHelpers.cs
+++ b/src/linker/Linker/ParameterHelpers.cs
@@ -2,9 +2,9 @@
 // Licensed under the MIT license. See LICENSE file in the project root for full license information.
 
 using System;
+using ILLink.Shared;
 using Mono.Cecil;
 using Mono.Cecil.Cil;
-using ILLink.Shared;
 
 namespace Mono.Linker
 {
diff --git a/src/linker/Linker/SerializationMarker.cs b/src/linker/Linker/SerializationMarker.cs
index feb0cb919..0f13544ea 100644
--- a/src/linker/Linker/SerializationMarker.cs
+++ b/src/linker/Linker/SerializationMarker.cs
@@ -58,8 +58,7 @@ namespace Mono.Linker
 		Dictionary<SerializerKind, HashSet<ICustomAttributeProvider>>? _trackedRoots;
 		Dictionary<SerializerKind, HashSet<ICustomAttributeProvider>> TrackedRoots {
 			get {
-				if (_trackedRoots == null)
-					_trackedRoots = new Dictionary<SerializerKind, HashSet<ICustomAttributeProvider>> ();
+				_trackedRoots ??= new Dictionary<SerializerKind, HashSet<ICustomAttributeProvider>> ();
 
 				return _trackedRoots;
 			}
@@ -68,8 +67,7 @@ namespace Mono.Linker
 		HashSet<TypeDefinition>? _recursiveTypes;
 		HashSet<TypeDefinition> RecursiveTypes {
 			get {
-				if (_recursiveTypes == null)
-					_recursiveTypes = new HashSet<TypeDefinition> ();
+				_recursiveTypes ??= new HashSet<TypeDefinition> ();
 
 				return _recursiveTypes;
 			}
diff --git a/src/linker/Linker/Tracer.cs b/src/linker/Linker/Tracer.cs
index 3da9dd51e..15bd8a4b3 100644
--- a/src/linker/Linker/Tracer.cs
+++ b/src/linker/Linker/Tracer.cs
@@ -61,9 +61,7 @@ namespace Mono.Linker
 
 		public void AddRecorder (IDependencyRecorder recorder)
 		{
-			if (recorders == null) {
-				recorders = new List<IDependencyRecorder> ();
-			}
+			recorders ??= new List<IDependencyRecorder> ();
 
 			recorders.Add (recorder);
 		}
diff --git a/src/linker/Linker/XmlDependencyRecorder.cs b/src/linker/Linker/XmlDependencyRecorder.cs
index c66383b14..6c386ac36 100644
--- a/src/linker/Linker/XmlDependencyRecorder.cs
+++ b/src/linker/Linker/XmlDependencyRecorder.cs
@@ -54,8 +54,7 @@ namespace Mono.Linker
 				IndentChars = "\t"
 			};
 
-			if (fileName == null)
-				fileName = DefaultDependenciesFileName;
+			fileName ??= DefaultDependenciesFileName;
 
 			if (string.IsNullOrEmpty (Path.GetDirectoryName (fileName)) && !string.IsNullOrEmpty (context.OutputDirectory)) {
 				fileName = Path.Combine (context.OutputDirectory, fileName);
diff --git a/test/ILLink.RoslynAnalyzer.Tests/RequiresAssemblyFilesAnalyzerTests.cs b/test/ILLink.RoslynAnalyzer.Tests/RequiresAssemblyFilesAnalyzerTests.cs
index fe377003e..cdc94089f 100644
--- a/test/ILLink.RoslynAnalyzer.Tests/RequiresAssemblyFilesAnalyzerTests.cs
+++ b/test/ILLink.RoslynAnalyzer.Tests/RequiresAssemblyFilesAnalyzerTests.cs
@@ -420,7 +420,7 @@ build_property.{MSBuildPropertyOptionNames.EnableSingleFileAnalyzer} = true")));
 			return VerifyRequiresAssemblyFilesCodeFix (
 				source: test,
 				fixedSource: fixtest,
-				baselineExpected:new[] {
+				baselineExpected: new[] {
 					// /0/Test0.cs(6,14): warning IL3002: Using member 'C.M1()' which has 'RequiresAssemblyFilesAttribute' can break functionality when embedded in a single-file app. message.
 					VerifyCS.Diagnostic(DiagnosticId.RequiresAssemblyFiles).WithSpan(6, 14, 6, 18).WithArguments("C.M1()", " message.", ""),
 					// /0/Test0.cs(10,24): warning IL3002: Using member 'C.M1()' which has 'RequiresAssemblyFilesAttribute' can break functionality when embedded in a single-file app. message.
diff --git a/test/ILLink.RoslynAnalyzer.Tests/UnconditionalSuppressMessageCodeFixTests.cs b/test/ILLink.RoslynAnalyzer.Tests/UnconditionalSuppressMessageCodeFixTests.cs
index c89330df1..4a9c2cf07 100644
--- a/test/ILLink.RoslynAnalyzer.Tests/UnconditionalSuppressMessageCodeFixTests.cs
+++ b/test/ILLink.RoslynAnalyzer.Tests/UnconditionalSuppressMessageCodeFixTests.cs
@@ -4,7 +4,6 @@
 using System;
 using System.Threading.Tasks;
 using ILLink.Shared;
-using Microsoft;
 using Microsoft.CodeAnalysis.Testing;
 using Microsoft.CodeAnalysis.Text;
 using Xunit;
diff --git a/test/Mono.Linker.Tests.Cases/Attributes/GenericAttributes.cs b/test/Mono.Linker.Tests.Cases/Attributes/GenericAttributes.cs
index 430fbc714..7ea46e419 100644
--- a/test/Mono.Linker.Tests.Cases/Attributes/GenericAttributes.cs
+++ b/test/Mono.Linker.Tests.Cases/Attributes/GenericAttributes.cs
@@ -6,64 +6,71 @@ namespace Mono.Linker.Tests.Cases.Attributes
 {
 	class GenericAttributes
 	{
-        static void Main ()
-        {
-            new WithGenericAttribute_OfString ();
-            new WithGenericAttribute_OfInt ();
-            new WithConstrainedGenericAttribute ();
-        }
+		static void Main ()
+		{
+			new WithGenericAttribute_OfString ();
+			new WithGenericAttribute_OfInt ();
+			new WithConstrainedGenericAttribute ();
+		}
 
-        [Kept]
-        [KeptAttributeAttribute (typeof (GenericAttribute<string>))]
-        [KeptMember (".ctor()")]
-        [GenericAttribute<string>("t", F = "f", P = "p")]
-        class WithGenericAttribute_OfString {
-        }
+		[Kept]
+		[KeptAttributeAttribute (typeof (GenericAttribute<string>))]
+		[KeptMember (".ctor()")]
+		[GenericAttribute<string> ("t", F = "f", P = "p")]
+		class WithGenericAttribute_OfString
+		{
+		}
 
-        [Kept]
-        [KeptAttributeAttribute (typeof (GenericAttribute<int>))]
-        [KeptMember (".ctor()")]
-        [GenericAttribute<int>(1, F = 2, P = 3)]
-        class WithGenericAttribute_OfInt {
-        }
+		[Kept]
+		[KeptAttributeAttribute (typeof (GenericAttribute<int>))]
+		[KeptMember (".ctor()")]
+		[GenericAttribute<int> (1, F = 2, P = 3)]
+		class WithGenericAttribute_OfInt
+		{
+		}
 
-        [Kept]
-        [KeptAttributeAttribute (typeof (ConstrainedGenericAttribute<DerivedFromConstraintType>))]
-        [KeptMember (".ctor()")]
-        [ConstrainedGenericAttribute<DerivedFromConstraintType>()]
-        class WithConstrainedGenericAttribute {
-        }
+		[Kept]
+		[KeptAttributeAttribute (typeof (ConstrainedGenericAttribute<DerivedFromConstraintType>))]
+		[KeptMember (".ctor()")]
+		[ConstrainedGenericAttribute<DerivedFromConstraintType> ()]
+		class WithConstrainedGenericAttribute
+		{
+		}
 
-        [KeptBaseType (typeof (Attribute))]
-        class GenericAttribute<T> : Attribute {
-            [Kept]
-            public GenericAttribute(T t) {}
+		[KeptBaseType (typeof (Attribute))]
+		class GenericAttribute<T> : Attribute
+		{
+			[Kept]
+			public GenericAttribute (T t) { }
 
-            [Kept]
-            public T F;
+			[Kept]
+			public T F;
 
-            [Kept]
-            [KeptBackingField]
-            public T P {
-                get;
-                [Kept]
-                set;
-            }
-        }
+			[Kept]
+			[KeptBackingField]
+			public T P {
+				get;
+				[Kept]
+				set;
+			}
+		}
 
-        [Kept]
-        class ConstraintType {
-        }
+		[Kept]
+		class ConstraintType
+		{
+		}
 
-        [KeptBaseType (typeof (ConstraintType))]
-        class DerivedFromConstraintType : ConstraintType {
-        }
+		[KeptBaseType (typeof (ConstraintType))]
+		class DerivedFromConstraintType : ConstraintType
+		{
+		}
 
-        [KeptBaseType (typeof (Attribute))]
-        class ConstrainedGenericAttribute<T> : Attribute
-            where T : ConstraintType {
-            [Kept]
-            public ConstrainedGenericAttribute() {}
-        }
-    }
+		[KeptBaseType (typeof (Attribute))]
+		class ConstrainedGenericAttribute<T> : Attribute
+			where T : ConstraintType
+		{
+			[Kept]
+			public ConstrainedGenericAttribute () { }
+		}
+	}
 }
\ No newline at end of file
diff --git a/test/Mono.Linker.Tests.Cases/DataFlow/MethodParametersDataFlow.cs b/test/Mono.Linker.Tests.Cases/DataFlow/MethodParametersDataFlow.cs
index 9629c54b6..99c7e8f99 100644
--- a/test/Mono.Linker.Tests.Cases/DataFlow/MethodParametersDataFlow.cs
+++ b/test/Mono.Linker.Tests.Cases/DataFlow/MethodParametersDataFlow.cs
@@ -241,7 +241,7 @@ namespace Mono.Linker.Tests.Cases.DataFlow
 
 		static void TestVarargsMethod ([DynamicallyAccessedMembers (DynamicallyAccessedMemberTypes.PublicMethods)] Type type, __arglist)
 		{
- 		}
+		}
 
 		class WriteCapturedParameter
 		{
diff --git a/test/Mono.Linker.Tests/TestCases/TestDatabase.cs b/test/Mono.Linker.Tests/TestCases/TestDatabase.cs
index da6dda038..6eec8ce77 100644
--- a/test/Mono.Linker.Tests/TestCases/TestDatabase.cs
+++ b/test/Mono.Linker.Tests/TestCases/TestDatabase.cs
@@ -249,8 +249,7 @@ namespace Mono.Linker.Tests.TestCases
 
 		static IEnumerable<TestCase> AllCases ()
 		{
-			if (_cachedAllCases == null)
-				_cachedAllCases = CreateCollector ()
+			_cachedAllCases ??= CreateCollector ()
 					.Collect ()
 					.OrderBy (c => c.DisplayName)
 					.ToArray ();