Simplify syntax

Author: danielmarbach

src/NServiceBus.Core/Persistence/PersistenceComponent.cs

@@ -6,6 +6,7 @@ namespace NServiceBus;
 using System.Collections.Generic;
 using System.Linq;
 using Features;
+using Persistence;
 using Logging;
 using Settings;
 
@@ -51,8 +52,8 @@ public static void ConfigurePersistence(this SettingsHolder settings)
 
     static void ValidateSagaAndOutboxUseSamePersistence(this SettingsHolder settings, IReadOnlyCollection<EnabledPersistence> enabledPersistences)
     {
-        var sagaPersisterDefinition = enabledPersistences.FirstOrDefault(p => p.SelectedStorages.Contains(StorageType.Sagas.Instance))?.Definition;
-        var outboxPersisterDefinition = enabledPersistences.FirstOrDefault(p => p.SelectedStorages.Contains(StorageType.Outbox.Instance))?.Definition;
+        var sagaPersisterDefinition = enabledPersistences.FirstOrDefault(p => p.SelectedStorages.Contains<StorageType.Sagas>())?.Definition;
+        var outboxPersisterDefinition = enabledPersistences.FirstOrDefault(p => p.SelectedStorages.Contains<StorageType.Outbox>())?.Definition;
         var bothFeaturesEnabled = settings.IsFeatureEnabled(typeof(Features.Sagas)) && settings.IsFeatureEnabled(typeof(Features.Outbox));
 
         if (sagaPersisterDefinition != null
@@ -68,7 +69,7 @@ internal static bool HasSupportFor<T>(this IReadOnlySettings settings) where T :
     {
         _ = settings.TryGet(out IReadOnlyCollection<StorageType> supportedStorages);
 
-        return supportedStorages?.Contains(StorageType.Get<T>()) ?? false;
+        return supportedStorages.Contains<T>();
     }
 
     static readonly ILog Logger = LogManager.GetLogger(typeof(PersistenceComponent));

src/NServiceBus.Core/Persistence/StorageTypeCollectionExtensions.cs

@@ -0,0 +1,23 @@
+#nullable enable
+
+namespace NServiceBus.Persistence;
+
+using System.Collections.Generic;
+using System.Linq;
+
+static class StorageTypeCollectionExtensions
+{
+    extension(IReadOnlyCollection<StorageType>? storageTypes)
+    {
+        public bool Contains<TStorage>() where TStorage : StorageType
+        {
+            if (storageTypes is null)
+            {
+                return false;
+            }
+
+            var storageType = StorageType.Get<TStorage>();
+            return storageTypes.Contains(storageType);
+        }
+    }
+}