diff --git a/RegExtract.Test/Usage.cs b/RegExtract.Test/Usage.cs
index 208aa78..b0f5d6b 100644
--- a/RegExtract.Test/Usage.cs
+++ b/RegExtract.Test/Usage.cs
@@ -94,6 +94,16 @@ public void a008()
             var result = plan.Extract(@"rn=1,cm-,qp=3,cm=2,qp-,pc=4,ot=9,ab=5,pc-,pc=6,ot=7");
         }
 
+        [Fact]
+        public void a009()
+        {
+            var plan = ExtractionPlan<List<List<List<char>>>>.CreatePlan(new Regex(@"(((\w)+ ?)+,? ?)+"));
+            var str = plan.ToString("x");
+            output.WriteLine(str);
+
+            var result = plan.Extract(@"asdf lkj, wero oiu");
+        }
+
         [Fact]
         public void slow()
         {
@@ -335,7 +345,11 @@ public void nested_extraction()
         [Fact]
         public void nested_extraction_of_list()
         {
-            var result = "The quick brown fox jumps over the lazy dog.".Extract<List<List<char>>>(@"(?:((\w)+) ?)+");
+            var plan = ExtractionPlan<List<List<char>>>.CreatePlan(new Regex(@"(((\w)+) ?)+"));
+            var str = plan.ToString("x");
+            output.WriteLine(str);
+            
+            var result = plan.Extract("The quick brown fox jumps over the lazy dog.");
         }
 
         [Fact]
@@ -418,7 +432,7 @@ public void CreateTreePlan()
             var plan = ExtractionPlan<((int?, int?)?, char, string)?>.CreatePlan(regex);
             object? result = plan.Extract(regex.Match("2-12 c: abcdefgji"));
 
-            regex = new Regex(@"(?:((\w)+) ?)+");
+            regex = new Regex(@"(((\w)+) ?)+");
             var plan2 = ExtractionPlan<List<List<char>>>.CreatePlan(regex);
 
             result = plan2.Extract(regex.Match("The quick brown fox jumps over the lazy dog"));
diff --git a/RegExtract/ExtractionPlan.cs b/RegExtract/ExtractionPlan.cs
index fd21b2a..e3bc0ef 100644
--- a/RegExtract/ExtractionPlan.cs
+++ b/RegExtract/ExtractionPlan.cs
@@ -53,8 +53,10 @@ internal void InitializePlan(Regex regex)
 
         // We use C#'s definition of an initializable collection, which is any type that implements IEnumerable and has a public Add() method.
         // In our case, we also require that the Add() method has parameters of the same type as the collection's generic parameters.
-        protected bool IsInitializableCollection(Type type)
+        protected bool IsInitializableCollection(Type? type)
         {
+            if (type == null)
+                return false;
             var genericParameters = type.GetGenericArguments();
             var addMethod = type.GetMethod("Add", BindingFlags.Public | BindingFlags.Instance, null, genericParameters, null);
 
@@ -239,7 +241,7 @@ private ExtractionPlanNode AssignTypesToTree(RegexCaptureGroupNode tree, Type ty
                     return new VirtualUnaryTupleNode(tree.name, type, new[] { AssignTypesToTree(tree.children.Single(), type) }, new ExtractionPlanNode[0]);
                 }
 
-                if (typeParams.Length < 2)
+                if (typeParams.Length < 2 && !IsInitializableCollection(typeParams.FirstOrDefault()))
                 {
                     return ExtractionPlanNode.Bind(tree.name, type, new[] { BindConstructorPlan(tree, type, 0, 1, stack) }, new ExtractionPlanNode[0]);
                 }