diff --git a/nt/CHECK_LIST.md b/nt/CHECK_LIST.md
index 7947333..d0e9dd8 100644
--- a/nt/CHECK_LIST.md
+++ b/nt/CHECK_LIST.md
@@ -1,3 +1,5 @@
+- [ ] mix should warn explicitly or have an "allowShadow" & "allowShadowPredicate"
+        decl option when content will be shadowed
 - [ ] mix should do a deeply nested merge, not a surface level merge
 - [ ] implement isomorphisms (especially from primitives to NixTypes)