Update src/Workspaces/Core/Portable/Storage/AbstractPersistentStorageService.cs

Co-Authored-By: NSam Harwell <sam@tunnelvisionlabs.com>

src/Workspaces/Core/Portable/Storage/AbstractPersistentStorageService.cs

@@ -213,7 +213,7 @@ public static IChecksummedPersistentStorage AddReferenceCountToAndCreateWrapper(
             {
                 // This should only be called from a caller that has a non-null storage that it
                 // already has a reference on.  So .TryAddReference cannot fail.
-                return new PersistentStorageReferenceCountedDisposableWrapper(storage.TryAddReference() ?? throw new InvalidOperationException());
+                return new PersistentStorageReferenceCountedDisposableWrapper(storage.TryAddReference() ?? throw ExceptionUtilities.Unreachable);
             }
 
             public void Dispose()