use some pattern matching

src/Adapter/MSTestAdapter.PlatformServices/Helpers/TestDataSourceHelpers.cs

@@ -29,7 +29,7 @@ public static bool TryHandleITestDataRow(
         out string? displayNameFromTestDataRow,
         out IList<string>? testCategoriesFromTestDataRow)
     {
-        if (d.Length == 1 && d[0] is ITestDataRow testDataRow)
+        if (d is [ITestDataRow testDataRow])
         {
             object? dataFromTestDataRow = testDataRow.Value;
             ignoreMessageFromTestDataRow = testDataRow.IgnoreMessage;

src/Analyzers/MSTest.Analyzers.CodeFixes/AvoidExpectedExceptionAttributeFixer.cs

@@ -133,9 +133,7 @@ private static (SyntaxNode ExpressionOrStatement, SyntaxNode NodeToReplace)? Try
             {
                 return (expressionStatement.Expression, statement);
             }
-            else if (statement is LocalDeclarationStatementSyntax localDeclarationStatementSyntax &&
-                localDeclarationStatementSyntax.Declaration.Variables.Count == 1 &&
-                localDeclarationStatementSyntax.Declaration.Variables[0].Initializer is { } initializer)
+            else if (statement is LocalDeclarationStatementSyntax { Declaration.Variables: [{ Initializer: { } initializer }] })
             {
                 return (initializer.Value, statement);
             }

src/Analyzers/MSTest.Analyzers/DataRowShouldBeValidAnalyzer.cs

@@ -295,7 +295,7 @@ private static void AnalyzeGenericMethod(
             // It also happens with [DataRow((object[]?)null)] which resolves
             // to the params object[] constructor
             // In this case, the argument is simply "null".
-            if (constructorArgument.Kind == TypedConstantKind.Array && constructorArgument.IsNull)
+            if (constructorArgument is { Kind: TypedConstantKind.Array, IsNull: true })
             {
                 continue;
             }

src/Analyzers/MSTest.Analyzers/DoNotNegateBooleanAssertionAnalyzer.cs

@@ -60,8 +60,7 @@ private static void AnalyzeOperation(OperationAnalysisContext context, INamedTyp
         }
 
         IArgumentOperation? conditionArgument = invocationOperation.Arguments.FirstOrDefault(x => x.Parameter?.Name == "condition");
-        if (conditionArgument != null
-            && conditionArgument.Value is IUnaryOperation { OperatorKind: UnaryOperatorKind.Not })
+        if (conditionArgument is { Value: IUnaryOperation { OperatorKind: UnaryOperatorKind.Not } })
         {
             context.ReportDiagnostic(invocationOperation.CreateDiagnostic(Rule));
         }

src/Analyzers/MSTest.Analyzers/DynamicDataShouldBeValidAnalyzer.cs

@@ -304,13 +304,11 @@ private static void AnalyzeDisplayNameSource(SymbolAnalysisContext context, Attr
                 continue;
             }
 
-            if (namedArgument.Key == "DynamicDataDisplayName"
-                && namedArgument.Value.Value is string name)
+            if (namedArgument is { Key: "DynamicDataDisplayName", Value.Value: string name })
             {
                 memberName = name;
             }
-            else if (namedArgument.Key == "DynamicDataDisplayNameDeclaringType"
-                && namedArgument.Value.Value is INamedTypeSymbol type)
+            else if (namedArgument is { Key: "DynamicDataDisplayNameDeclaringType", Value.Value: INamedTypeSymbol type })
             {
                 declaringType = type;
             }

src/Analyzers/MSTest.Analyzers/RoslynAnalyzerHelpers/ITypeSymbolExtensions.cs

@@ -87,7 +87,7 @@ public static bool DerivesFrom([NotNullWhen(returnValue: true)] this ITypeSymbol
     }
 
     public static bool IsNullableValueType([NotNullWhen(returnValue: true)] this ITypeSymbol? typeSymbol)
-        => typeSymbol != null && typeSymbol.IsValueType && typeSymbol.OriginalDefinition.SpecialType == SpecialType.System_Nullable_T;
+        => typeSymbol is { IsValueType: true } && typeSymbol.OriginalDefinition.SpecialType == SpecialType.System_Nullable_T;
 
     public static bool IsNullableOfBoolean([NotNullWhen(returnValue: true)] this ITypeSymbol? typeSymbol)
         => typeSymbol.IsNullableValueType() && ((INamedTypeSymbol)typeSymbol).TypeArguments[0].SpecialType == SpecialType.System_Boolean;

src/Analyzers/MSTest.Analyzers/TestContextShouldBeValidAnalyzer.cs

@@ -92,12 +92,11 @@ private static bool AssignsParameterToMember(IParameterSymbol parameter, ISymbol
             operation = expressionStatementOperation.Operation;
         }
 
-        if (operation is ISimpleAssignmentOperation assignmentOperation &&
-            assignmentOperation.Target is IMemberReferenceOperation targetMemberReference &&
-            SymbolEqualityComparer.Default.Equals(targetMemberReference.Member, member))
+        if (operation is ISimpleAssignmentOperation { Target: IMemberReferenceOperation { Member: { } targetMember }, Value: { } assignmentValue } &&
+            SymbolEqualityComparer.Default.Equals(targetMember, member))
         {
             // Extract parameter reference from the value, unwrapping from coalesce operation if necessary
-            IOperation effectiveValue = assignmentOperation.Value;
+            IOperation effectiveValue = assignmentValue;
             if (effectiveValue is ICoalesceOperation coalesceOperation)
             {
                 effectiveValue = coalesceOperation.Value;
@@ -139,8 +138,7 @@ private static void CollectTestContextFieldsAssignedInConstructor(
             operation = expressionStatementOperation.Operation;
         }
 
-        if (operation is ISimpleAssignmentOperation assignmentOperation &&
-            assignmentOperation.Target is IMemberReferenceOperation { Member: IFieldSymbol { } candidateField })
+        if (operation is ISimpleAssignmentOperation { Target: IMemberReferenceOperation { Member: IFieldSymbol candidateField } } assignmentOperation)
         {
             // Extract parameter reference from the value, unwrapping from coalesce operation if necessary
             IOperation effectiveValue = assignmentOperation.Value;

src/Analyzers/MSTest.Analyzers/UseCooperativeCancellationForTimeoutAnalyzer.cs

@@ -68,7 +68,7 @@ private static void AnalyzeSymbol(SymbolAnalysisContext context, INamedTypeSymbo
 
         // Report diagnostic if CooperativeCancellation is not explicitly set to true
         if (timeoutAttribute is not null
-            && !timeoutAttribute.NamedArguments.Any(x => x.Key == "CooperativeCancellation" && x.Value.Value is bool boolValue && boolValue))
+            && !timeoutAttribute.NamedArguments.Any(x => x is { Key: "CooperativeCancellation", Value.Value: true }))
         {
             if (timeoutAttribute.ApplicationSyntaxReference?.GetSyntax() is { } syntax)
             {

src/Analyzers/MSTest.GlobalConfigsGenerator/AnalyzerSeverityDecider.cs

@@ -83,7 +83,7 @@ internal static class AnalyzerSeverityDecider
             return DiagnosticSeverity.Error;
         }
 
-        if (rule.IsEnabledByDefault && rule.DefaultSeverity >= DiagnosticSeverity.Info)
+        if (rule is { IsEnabledByDefault: true, DefaultSeverity: >= DiagnosticSeverity.Info })
         {
             // Recommended mode will elevate info to warning only if the rule is enabled by default.
             return DiagnosticSeverity.Warning;
@@ -101,7 +101,7 @@ internal static class AnalyzerSeverityDecider
 
     private static DiagnosticSeverity? DecideForModeDefault(DiagnosticDescriptor rule)
     {
-        if (rule.IsEnabledByDefault && rule.DefaultSeverity >= DiagnosticSeverity.Warning)
+        if (rule is { IsEnabledByDefault: true, DefaultSeverity: >= DiagnosticSeverity.Warning })
         {
             // Default mode will enable warnings only if the rule is enabled by default.
             return rule.DefaultSeverity;

src/Analyzers/MSTest.SourceGeneration/Helpers/AttributeDataExtensions.cs

@@ -21,9 +21,7 @@ public static bool TryGetTestExecutionTimeout(this AttributeData attribute, INam
 
     private static bool TryGetTimeoutValue(this AttributeData attribute, INamedTypeSymbol? timeSpanSymbol, out TimeSpan timeout)
     {
-        if (attribute.ConstructorArguments.Length == 1
-            && attribute.ConstructorArguments[0].Type is { } executionTimeoutCtorArgType
-            && attribute.ConstructorArguments[0].Value is { } executionTimeoutCtorArgValue)
+        if (attribute.ConstructorArguments is [{ Type: { } executionTimeoutCtorArgType, Value: { } executionTimeoutCtorArgValue }])
         {
             if (executionTimeoutCtorArgType.SpecialType is SpecialType.System_Int32 or SpecialType.System_Int64)
             {

src/Analyzers/MSTest.SourceGeneration/Helpers/IMethodSymbolExtensions.cs

@@ -23,9 +23,8 @@ public static bool IsDisposeImplementation(this IMethodSymbol? method, INamedTyp
 
         // Identify the implementor of IDisposable.Dispose in the given method's containing type and check
         // if it is the given method.
-        return method.ReturnsVoid
-            && method.Parameters.IsEmpty
-            && method.IsImplementationOfInterfaceMethod(null, iDisposable, "Dispose");
+        return method is { ReturnsVoid: true, Parameters.IsEmpty: true }
+               && method.IsImplementationOfInterfaceMethod(null, iDisposable, "Dispose");
     }
 
     /// <summary>

src/Analyzers/MSTest.SourceGeneration/Helpers/TestMethods.cs

@@ -47,7 +47,7 @@ public static bool IsValidTestMethodShape(this IMethodSymbol methodSymbol, WellK
         }
 
         // We don't support async void
-        if (methodSymbol.ReturnsVoid && methodSymbol.IsAsync)
+        if (methodSymbol is { ReturnsVoid: true, IsAsync: true })
         {
             return false;
         }

src/Analyzers/MSTest.SourceGeneration/MSTest.SourceGeneration.csproj

@@ -3,6 +3,8 @@
   <PropertyGroup>
     <!-- C# Source generators have to target netstandard -->
     <TargetFrameworks>netstandard2.0</TargetFrameworks>
+    <!-- Disable Polyfill validation for source generators -->
+    <PolyfillTargetsForNuget>true</PolyfillTargetsForNuget>
     <!-- Generates a package at build -->
     <GeneratePackageOnBuild>true</GeneratePackageOnBuild>
     <!-- Do not include the generator as a lib dependency -->
@@ -46,6 +48,7 @@ This package provides the C# source generators for MSTest test framework.]]>
     <PackageReference Include="Microsoft.CodeAnalysis.CSharp" PrivateAssets="all" />
     <!-- Analyzers to help write analyzers/generators -->
     <PackageReference Include="Microsoft.CodeAnalysis.Analyzers" PrivateAssets="all" />
+    <PackageReference Include="Polyfill" PrivateAssets="all" />
   </ItemGroup>
 
   <ItemGroup>

src/Analyzers/MSTest.SourceGeneration/ObjectModels/DataRowTestMethodArgumentsInfo.cs

@@ -110,8 +110,7 @@ private static IEnumerable<string> GetInlineArguments(IMethodSymbol methodSymbol
         Stack<(TypedConstant Argument, bool HasNextArg, bool IsInArray, int ClosingCurlyBraceCount)> argumentStack = new();
 
         bool hasManyArgsButExpectsSingleArray =
-            methodSymbol.Parameters.Length == 1
-            && methodSymbol.Parameters[0].Type.TypeKind == TypeKind.Array
+            methodSymbol.Parameters is [{ Type.TypeKind: TypeKind.Array }]
             && argumentsAttributeArguments.Values.Length > 1;
 
         if (hasManyArgsButExpectsSingleArray)

src/Platform/Microsoft.Testing.Extensions.CrashDump/CrashDumpProcessLifetimeHandler.cs

@@ -57,7 +57,7 @@ public async Task OnTestHostProcessExitedAsync(ITestHostProcessInformation testH
     {
         if (cancellation.IsCancellationRequested
             || testHostProcessInformation.HasExitedGracefully
-            || (AppDomain.CurrentDomain.GetData("ProcessKilledByHangDump") is string processKilledByHangDump && processKilledByHangDump == "true"))
+            || AppDomain.CurrentDomain.GetData("ProcessKilledByHangDump") is "true")
         {
             return;
         }

src/Platform/Microsoft.Testing.Platform/OutputDevice/Terminal/AnsiTerminalTestProgressFrame.cs

@@ -178,7 +178,7 @@ public void Render(AnsiTerminalTestProgressFrame previousFrame, TestProgressStat
         //   quickly determine if the detail has changed since the last render.
 
         // Don't go up if we did not render any lines in previous frame or we already cleared them.
-        if (previousFrame.RenderedLines != null && previousFrame.RenderedLines.Count > 0)
+        if (previousFrame.RenderedLines is { Count: > 0 })
         {
             // Move cursor back to 1st line of progress.
             // + 2 because we output and empty line right below.

src/Platform/Microsoft.Testing.Platform/Services/CurrentTestApplicationModuleInfo.cs

@@ -26,9 +26,7 @@ public bool IsCurrentTestApplicationHostMonoMuxer
         get
         {
             string? processPath = GetProcessPath(_environment, _process);
-            return processPath is not null
-                && Path.GetFileNameWithoutExtension(processPath) is { } processName
-                && processName is "mono" or "mono-sgen";
+            return Path.GetFileNameWithoutExtension(processPath) is "mono" or "mono-sgen";
         }
     }
 

test/UnitTests/MSTestAdapter.PlatformServices.UnitTests/Discovery/TypeEnumeratorTests.cs

@@ -404,7 +404,7 @@ public void GetTestFromMethodShouldSetDescription()
         MSTest.TestAdapter.ObjectModel.UnitTestElement testElement = typeEnumerator.GetTestFromMethod(methodInfo, true, _warnings);
 
         Verify(testElement.Traits is not null);
-        Verify(testElement.Traits.Any(t => t.Name == "Description" && t.Value == "Dummy description"));
+        Verify(testElement.Traits.Any(t => t is { Name: "Description", Value: "Dummy description" }));
     }
 
     public void GetTestFromMethodShouldSetWorkItemIds()

test/Utilities/Microsoft.Testing.TestInfrastructure/DotnetCli.cs

@@ -99,7 +99,7 @@ public static async Task<DotnetMuxerResult> RunAsync(
 
             string extraArgs = warnAsError ? " /warnaserror" : string.Empty;
             extraArgs += suppressPreviewDotNetMessage ? " -p:SuppressNETCoreSdkPreviewMessage=true" : string.Empty;
-            if (args.IndexOf("-- ", StringComparison.Ordinal) is int platformArgsIndex && platformArgsIndex > 0)
+            if (args.IndexOf("-- ", StringComparison.Ordinal) is int platformArgsIndex and > 0)
             {
                 args = args.Insert(platformArgsIndex, extraArgs + " ");
             }
@@ -150,7 +150,7 @@ private static async Task<DotnetMuxerResult> CallTheMuxerCoreAsync(string args,
             // We do this here rather than in the caller so that different retries produce different binlog file names.
             binlogFullPath = Path.Combine(TempDirectory.TestSuiteDirectory, $"{binlogBaseFileName}-{Interlocked.Increment(ref s_binlogCounter)}.binlog");
             string binlogArg = $" -bl:\"{binlogFullPath}\"";
-            if (args.IndexOf("-- ", StringComparison.Ordinal) is int platformArgsIndex && platformArgsIndex > 0)
+            if (args.IndexOf("-- ", StringComparison.Ordinal) is int platformArgsIndex and > 0)
             {
                 args = args.Insert(platformArgsIndex, binlogArg + " ");
             }