Review feedback:

- Throw if delayed fixup is left in an invalid state
- Store arguments rather than delegate

src/EFCore/ChangeTracking/Internal/NavigationFixer.cs

@@ -14,7 +14,13 @@ namespace Microsoft.EntityFrameworkCore.ChangeTracking.Internal;
 /// </summary>
 public class NavigationFixer : INavigationFixer
 {
-    private IList<Action>? _danglingJoinEntities;
+    private IList<(
+            InternalEntityEntry Entry,
+            InternalEntityEntry OtherEntry,
+            ISkipNavigation SkipNavigation,
+            bool FromQuery,
+            bool SetModified)>? _danglingJoinEntities;
+
     private readonly IEntityGraphAttacher _attacher;
     private bool _inFixup;
     private bool _inAttachGraph;
@@ -43,7 +49,11 @@ public virtual bool BeginDelayedFixup()
             return false;
         }
 
-        _danglingJoinEntities?.Clear();
+        if (_danglingJoinEntities != null)
+        {
+            throw new InvalidOperationException(CoreStrings.InvalidDbContext);
+        }
+
         _inAttachGraph = true;
 
         return true;
@@ -61,10 +71,10 @@ public virtual void CompleteDelayedFixup()
         if (_danglingJoinEntities != null)
         {
             var dangles = _danglingJoinEntities.ToList();
-            _danglingJoinEntities.Clear();
-            foreach (var synthesize in dangles)
+            _danglingJoinEntities = null;
+            foreach (var arguments in dangles)
             {
-                synthesize();
+                FindOrCreateJoinEntry(arguments);
             }
         }
     }
@@ -1009,9 +1019,15 @@ private void FindOrCreateJoinEntry(
         }
         else
         {
-            _danglingJoinEntities ??= new List<Action>();
-
-            _danglingJoinEntities.Add(() => FindOrCreateJoinEntry(arguments));
+            _danglingJoinEntities ??=
+                new List<(
+                    InternalEntityEntry Entry,
+                    InternalEntityEntry OtherEntry,
+                    ISkipNavigation SkipNavigation,
+                    bool FromQuery,
+                    bool SetModified)>();
+
+            _danglingJoinEntities.Add(arguments);
         }
     }
 

src/EFCore/Properties/CoreStrings.resx

@@ -547,6 +547,9 @@
   <data name="InvalidAlternateKeyValue" xml:space="preserve">
     <value>Unable to track an entity of type '{entityType}' because alternate key property '{keyProperty}' is null. If the alternate key is not used in a relationship, then consider using a unique index instead. Unique indexes may contain nulls, while alternate keys may not.</value>
   </data>
+  <data name="InvalidDbContext" xml:space="preserve">
+    <value>A previous error has left the DbContext in an invalid state. Applications should not continue to use a DbContext instance after an InvalidOperationException has been thrown.</value>
+  </data>
   <data name="InvalidEntityType" xml:space="preserve">
     <value>The specified type '{type}' must be a non-interface reference type to be used as an entity type.</value>
   </data>