1 files changed, 6 insertions, 1 deletions
diff --git a/neb/__init__.py b/neb/__init__.py
index 099bc2a..735e4db 100644
--- a/neb/__init__.py
+++ b/neb/__init__.py
@@ -215,4 +215,9 @@ class NebType(TypeWrap):
     pass
 
 class UserType(TypeWrap):
-    pass
+
+    def __init__(self, name, parent, is_func):
+        if name in ALL_TYPES:
+            raise NebPanic(f"already a type called {name}")
+        ALL_TYPES[name] = Type(name)
+        super().__init__(name, parent, is_func)