diff --git a/source/MetadataProcessor.Core/Tables/nanoSignaturesTable.cs b/source/MetadataProcessor.Core/Tables/nanoSignaturesTable.cs
index 3783381e..85040065 100644
--- a/source/MetadataProcessor.Core/Tables/nanoSignaturesTable.cs
+++ b/source/MetadataProcessor.Core/Tables/nanoSignaturesTable.cs
@@ -225,14 +225,24 @@ public void WriteDataType(
             bool expandEnumType,
             bool isTypeDefinition)
         {
-            if (!isTypeDefinition)
+            if (isTypeDefinition)
             {
-                nanoCLR_DataType dataType;
-                if (PrimitiveTypes.TryGetValue(typeDefinition.FullName, out dataType))
+                if (typeDefinition.MetadataType == MetadataType.Object)
                 {
-                    writer.WriteByte((byte)dataType);
+                    writer.WriteByte((byte)nanoCLR_DataType.DATATYPE_CLASS);
                     return;
                 }
+                else
+                {
+
+                }
+            }
+
+            nanoCLR_DataType dataType;
+            if (PrimitiveTypes.TryGetValue(typeDefinition.FullName, out dataType))
+            {
+                writer.WriteByte((byte)dataType);
+                return;
             }
 
             if (typeDefinition is TypeSpecification)
@@ -283,12 +293,6 @@ public void WriteDataType(
                 return;
             }
 
-            if(typeDefinition.MetadataType == MetadataType.Object)
-            {
-                writer.WriteByte((byte)nanoCLR_DataType.DATATYPE_CLASS);
-                return;
-            }
-
             writer.WriteByte(0x00);
         }