Use C# 12 collection expressions

src/NServiceBus.AcceptanceTesting/AcceptanceTestingPersistence/SagaPersister/AcceptanceTestingSagaPersister.cs

@@ -114,7 +114,7 @@ static void SetEntry(ContextBag context, Guid sagaId, Entry value)
         {
             if (context.TryGet(ContextKey, out Dictionary<Guid, Entry> entries) == false)
             {
-                entries = new Dictionary<Guid, Entry>();
+                entries = [];
                 context.Set(ContextKey, entries);
             }
             entries[sagaId] = value;

src/NServiceBus.AcceptanceTesting/Support/EndpointBehavior.cs

@@ -11,7 +11,7 @@ public class EndpointBehavior : IComponentBehavior
         public EndpointBehavior(IEndpointConfigurationFactory endpointBuilder)
         {
             EndpointBuilder = endpointBuilder;
-            CustomConfig = new List<Action<EndpointConfiguration, ScenarioContext>>();
+            CustomConfig = [];
             ConfigureHowToCreateInstance(config => Endpoint.Create(config), startable => startable.Start());
         }
 

src/NServiceBus.AcceptanceTesting/Support/FeatureStartupTaskRunner.cs

@@ -53,7 +53,7 @@ static List<Func<IServiceProvider, FeatureStartupTask>> GetStartupTaskRegistrati
         {
             if (!endpointConfiguration.Settings.TryGet<List<Func<IServiceProvider, FeatureStartupTask>>>(FeatureStartupTaskRunner.ConfigKey, out var startupTasks))
             {
-                startupTasks = new List<Func<IServiceProvider, FeatureStartupTask>>();
+                startupTasks = [];
                 endpointConfiguration.Settings.Set(FeatureStartupTaskRunner.ConfigKey, startupTasks);
             }
 

src/NServiceBus.AcceptanceTests/Core/AutomaticSubscriptions/When_excluding_event_type_from_autosubscribe.cs

@@ -32,7 +32,7 @@ class Context : ScenarioContext
         {
             public Context()
             {
-                EventsSubscribedTo = new List<Type>();
+                EventsSubscribedTo = [];
             }
 
             public List<Type> EventsSubscribedTo { get; }

src/NServiceBus.AcceptanceTests/Core/AutomaticSubscriptions/When_starting_an_endpoint_with_a_saga.cs

@@ -27,7 +27,7 @@ class Context : ScenarioContext
         {
             public Context()
             {
-                EventsSubscribedTo = new List<Type>();
+                EventsSubscribedTo = [];
             }
 
             public List<Type> EventsSubscribedTo { get; }

src/NServiceBus.AcceptanceTests/Core/AutomaticSubscriptions/When_starting_an_endpoint_with_a_saga_autosubscribe_disabled.cs

@@ -27,7 +27,7 @@ class Context : ScenarioContext
         {
             public Context()
             {
-                EventsSubscribedTo = new List<Type>();
+                EventsSubscribedTo = [];
             }
 
             public List<Type> EventsSubscribedTo { get; }

src/NServiceBus.AcceptanceTests/Core/AutomaticSubscriptions/When_starting_an_endpoint_with_autosubscribe.cs

@@ -32,7 +32,7 @@ class Context : ScenarioContext
         {
             public Context()
             {
-                EventsSubscribedTo = new List<string>();
+                EventsSubscribedTo = [];
             }
 
             public List<string> EventsSubscribedTo { get; }

src/NServiceBus.Core.Tests/Pipeline/BehaviorRegistrationsCoordinatorTests.cs

@@ -17,8 +17,8 @@ class BehaviorRegistrationsCoordinatorTests
         [SetUp]
         public void Setup()
         {
-            replacements = new List<ReplaceStep>();
-            addOrReplacements = new List<RegisterOrReplaceStep>();
+            replacements = [];
+            addOrReplacements = [];
 
             coordinator = new StepRegistrationsCoordinator(replacements, addOrReplacements);
         }

src/NServiceBus.Core.Tests/Serializers/XML/Pull_819.cs

@@ -18,7 +18,7 @@ public void Should_check_for_ignore_attribute_before_checking_type()
 #pragma warning disable DE0006
                 m3.List = new ArrayList();
 #pragma warning restore DE0006
-                m3.GenericList = new List<string>();
+                m3.GenericList = [];
             });
 
             Assert.AreEqual("John", result.FirstName);

src/NServiceBus.Core.Tests/Serializers/XML/SerializerTests.cs

@@ -716,7 +716,7 @@ public void TestInterfaces()
                 Accuracy = 0.314M
             };
 
-            o.Names = new List<IFirstSerializableMessage>();
+            o.Names = [];
             for (var i = 0; i < number; i++)
             {
                 var firstMessage = mapper.CreateInstance<IFirstSerializableMessage>();
@@ -822,13 +822,13 @@ public void SerializeLists()
             var serializer = SerializerFactory.Create<MessageWithList>();
             var msg = mapper.CreateInstance<MessageWithList>();
 
-            msg.Items = new List<MessageWithListItem>
-            {
+            msg.Items =
+            [
                 new MessageWithListItem
                 {
                     Data = "Hello"
                 }
-            };
+            ];
 
             using (var stream = new MemoryStream())
             {
@@ -848,13 +848,13 @@ public void SerializeClosedGenericListsInAlternateNamespace()
             var serializer = SerializerFactory.Create<MessageWithClosedListInAlternateNamespace>();
             var msg = mapper.CreateInstance<MessageWithClosedListInAlternateNamespace>();
 
-            msg.Items = new AlternateItemList
-            {
+            msg.Items =
+            [
                 new MessageWithListItemAlternate
                 {
                     Data = "Hello"
                 }
-            };
+            ];
 
             using (var stream = new MemoryStream())
             {
@@ -874,13 +874,13 @@ public void SerializeClosedGenericListsInAlternateNamespaceMultipleIEnumerableIm
             var serializer = SerializerFactory.Create<MessageWithClosedListInAlternateNamespaceMultipleIEnumerableImplementations>();
             var msg = mapper.CreateInstance<MessageWithClosedListInAlternateNamespaceMultipleIEnumerableImplementations>();
 
-            msg.Items = new AlternateItemListMultipleIEnumerableImplementations
-            {
+            msg.Items =
+            [
                 new MessageWithListItemAlternate
                 {
                     Data = "Hello"
                 }
-            };
+            ];
 
             using (var stream = new MemoryStream())
             {
@@ -900,13 +900,13 @@ public void SerializeClosedGenericListsInAlternateNamespaceMultipleIListImplemen
             var serializer = SerializerFactory.Create<MessageWithClosedListInAlternateNamespaceMultipleIListImplementations>();
             var msg = mapper.CreateInstance<MessageWithClosedListInAlternateNamespaceMultipleIListImplementations>();
 
-            msg.Items = new AlternateItemListMultipleIListImplementations
-            {
+            msg.Items =
+            [
                 new MessageWithListItemAlternate
                 {
                     Data = "Hello"
                 }
-            };
+            ];
 
             using (var stream = new MemoryStream())
             {
@@ -926,13 +926,13 @@ public void SerializeClosedGenericListsInSameNamespace()
             var serializer = SerializerFactory.Create<MessageWithClosedList>();
             var msg = mapper.CreateInstance<MessageWithClosedList>();
 
-            msg.Items = new ItemList
-            {
+            msg.Items =
+            [
                 new MessageWithListItem
                 {
                     Data = "Hello"
                 }
-            };
+            ];
 
             using (var stream = new MemoryStream())
             {
@@ -952,7 +952,7 @@ public void SerializeEmptyLists()
             var serializer = SerializerFactory.Create<MessageWithList>();
             var msg = mapper.CreateInstance<MessageWithList>();
 
-            msg.Items = new List<MessageWithListItem>();
+            msg.Items = [];
 
             using (var stream = new MemoryStream())
             {

src/NServiceBus.Core/Audit/AuditContext.cs

@@ -16,7 +16,7 @@ public AuditContext(OutgoingMessage message, string auditAddress, TimeSpan? time
             Message = message;
             AuditAddress = auditAddress;
             TimeToBeReceived = timeToBeReceived;
-            AuditMetadata = new Dictionary<string, string>();
+            AuditMetadata = [];
             AuditAction = RouteToAudit.Instance;
         }
 

src/NServiceBus.Core/Extensibility/ExtendableOptions.cs

@@ -19,7 +19,7 @@ public abstract class ExtendableOptions
         protected ExtendableOptions()
         {
             Context = new ContextBag();
-            OutgoingHeaders = new Dictionary<string, string>();
+            OutgoingHeaders = [];
         }
 
         internal DispatchProperties DispatchProperties { get; } = new DispatchProperties();

src/NServiceBus.Core/Features/Feature.cs

@@ -15,7 +15,7 @@ public abstract class Feature
         /// </summary>
         protected Feature()
         {
-            Dependencies = new List<List<string>>();
+            Dependencies = [];
             Name = GetFeatureName(GetType());
         }
 

src/NServiceBus.Core/Features/FeatureConfigurationContext.cs

@@ -25,7 +25,7 @@ internal FeatureConfigurationContext(
             Routing = routing;
             this.receiveConfiguration = receiveConfiguration;
 
-            TaskControllers = new List<FeatureStartupTaskController>();
+            TaskControllers = [];
         }
 
         /// <summary>

src/NServiceBus.Core/Features/PrerequisiteStatus.cs

@@ -6,7 +6,7 @@ class PrerequisiteStatus
     {
         internal PrerequisiteStatus()
         {
-            Reasons = new List<string>();
+            Reasons = [];
             IsSatisfied = true;
         }
 

src/NServiceBus.Core/Hosting/Helpers/AssemblyScannerResults.cs

@@ -16,9 +16,9 @@ public class AssemblyScannerResults
         /// </summary>
         public AssemblyScannerResults()
         {
-            Assemblies = new List<Assembly>();
-            Types = new List<Type>();
-            SkippedFiles = new List<SkippedFile>();
+            Assemblies = [];
+            Types = [];
+            SkippedFiles = [];
         }
 
         /// <summary>

src/NServiceBus.Core/Hosting/Helpers/AssemblyScanningComponent.cs

@@ -21,7 +21,7 @@ public static AssemblyScanningComponent Initialize(Configuration configuration,
                 var directoryToScan = AppDomain.CurrentDomain.RelativeSearchPath ?? AppDomain.CurrentDomain.BaseDirectory;
 
                 assemblyScanner = new AssemblyScanner(directoryToScan);
-                availableTypes = new List<Type>();
+                availableTypes = [];
             }
             else
             {

src/NServiceBus.Core/Persistence/PersistenceExtensions.cs

@@ -60,7 +60,7 @@ public PersistenceExtensions(Type definitionType, SettingsHolder settings, Type
         {
             if (!Settings.TryGet("PersistenceDefinitions", out List<EnabledPersistence> definitions))
             {
-                definitions = new List<EnabledPersistence>();
+                definitions = [];
                 Settings.Set("PersistenceDefinitions", definitions);
             }
 

src/NServiceBus.Core/Pipeline/Outgoing/RoutingContextExtensions.cs

@@ -13,7 +13,7 @@ public static TransportOperation ToTransportOperation(this IRoutingContext conte
 
             if (!context.Extensions.TryGet(out DispatchProperties dispatchProperties))
             {
-                dispatchProperties = new DispatchProperties();
+                dispatchProperties = [];
             }
 
             var transportOperation = new TransportOperation(message, addressLabel, dispatchProperties, dispatchConsistency);

src/NServiceBus.Core/Pipeline/Pipeline.cs

@@ -29,7 +29,7 @@ public Pipeline(IServiceProvider builder, PipelineModifications pipelineModifica
             List<Expression> expressions = null;
             if (Logger.IsDebugEnabled)
             {
-                expressions = new List<Expression>();
+                expressions = [];
             }
 
             pipeline = behaviors.CreatePipelineExecutionFuncFor<TContext>(expressions);

src/NServiceBus.Core/Receiving/ReceiveComponent.Configuration.cs

@@ -73,7 +73,7 @@ public Configuration(string queueNameBase,
                 IsSendOnlyEndpoint = isSendOnlyEndpoint;
                 PipelineCompletedSubscribers = pipelineCompletedSubscribers;
                 ExecuteTheseHandlersFirst = executeTheseHandlersFirst;
-                satelliteDefinitions = new List<SatelliteDefinition>();
+                satelliteDefinitions = [];
                 this.messageHandlerRegistry = messageHandlerRegistry;
                 CreateQueues = createQueues;
                 Conventions = conventions;

src/NServiceBus.Core/Recoverability/RecoverabilitySettingsExtensions.cs

@@ -26,7 +26,7 @@ public static void AddUnrecoverableException(this SettingsHolder settings, Type
 
             if (!settings.TryGet(RecoverabilityComponent.UnrecoverableExceptions, out HashSet<Type> unrecoverableExceptions))
             {
-                unrecoverableExceptions = new HashSet<Type>();
+                unrecoverableExceptions = [];
                 settings.Set(RecoverabilityComponent.UnrecoverableExceptions, unrecoverableExceptions);
             }
 

src/NServiceBus.Core/Routing/EndpointInstances.cs

@@ -44,7 +44,7 @@ public void AddOrReplaceInstances(string sourceKey, IList<EndpointInstance> endp
                 {
                     if (!newCache.TryGetValue(instance.Endpoint, out var instanceSet))
                     {
-                        instanceSet = new HashSet<EndpointInstance>();
+                        instanceSet = [];
                         newCache[instance.Endpoint] = instanceSet;
                     }
                     instanceSet.Add(instance);

src/NServiceBus.Core/Routing/MessageDrivenSubscriptions/Publishers.cs

@@ -35,7 +35,7 @@ public void AddOrReplacePublishers(string sourceKey, IList<PublisherTableEntry>
                 {
                     if (!newRouteTable.TryGetValue(entry.EventType, out var publishersOfThisEvent))
                     {
-                        publishersOfThisEvent = new HashSet<PublisherAddress>();
+                        publishersOfThisEvent = [];
                         newRouteTable[entry.EventType] = publishersOfThisEvent;
                     }
                     publishersOfThisEvent.Add(entry.Address);

src/NServiceBus.Core/Routing/UnicastPublishRouter.cs

@@ -69,7 +69,7 @@ Dictionary<string, UnicastRoutingStrategy>.ValueCollection SelectDestinationsFor
                 }
                 else
                 {
-                    groups[subscriber.Endpoint] = new List<string> { subscriber.TransportAddress };
+                    groups[subscriber.Endpoint] = [subscriber.TransportAddress];
                 }
             }
 

src/NServiceBus.Core/Sagas/SagaMetadata.cs

@@ -48,14 +48,14 @@ public SagaMetadata(string name, Type sagaType, string entityName, Type sagaEnti
                 }
             }
 
-            associatedMessages = new Dictionary<string, SagaMessage>();
+            associatedMessages = [];
 
             foreach (var sagaMessage in messages)
             {
                 associatedMessages[sagaMessage.MessageTypeName] = sagaMessage;
             }
 
-            sagaFinders = new Dictionary<string, SagaFinderDefinition>();
+            sagaFinders = [];
 
             foreach (var finder in finders)
             {

src/NServiceBus.Core/Serialization/SerializationSettingsExtensions.cs

@@ -16,7 +16,7 @@ public static List<Tuple<SerializationDefinition, SettingsHolder>> GetAdditional
         {
             if (!settings.TryGet(AdditionalSerializersSettingsKey, out List<Tuple<SerializationDefinition, SettingsHolder>> deserializers))
             {
-                deserializers = new List<Tuple<SerializationDefinition, SettingsHolder>>();
+                deserializers = [];
                 settings.Set(AdditionalSerializersSettingsKey, deserializers);
             }
             return deserializers;

src/NServiceBus.Core/StaticHeaders/StaticHeadersConfigExtensions.cs

@@ -20,7 +20,7 @@ public static void AddHeaderToAllOutgoingMessages(this EndpointConfiguration con
 
             if (!config.Settings.TryGet(out CurrentStaticHeaders headers))
             {
-                headers = new CurrentStaticHeaders();
+                headers = [];
 
                 config.Settings.Set(headers);
             }

src/NServiceBus.TransportTests/NServiceBusTransportTest.cs

@@ -31,7 +31,7 @@ public void SetUp()
             configurer = null;
             testCancellationTokenSource = Debugger.IsAttached ? new CancellationTokenSource() : new CancellationTokenSource(TestTimeout);
             receiver = null;
-            registrations = new List<CancellationTokenRegistration>();
+            registrations = [];
         }
         protected static IConfigureTransportInfrastructure CreateConfigurer()
         {