diff --git a/TODO.txt b/TODO.txt
index 4b5eee8..0c60145 100644
--- a/TODO.txt
+++ b/TODO.txt
@@ -10,4 +10,9 @@ Inject error handling into parser and scanner
 Think about a way to hide record fields
 	- Maybe a compile-time primitive for generating globally unique symbols?
 		Would also need a syntax to use those symbols.
-	- Use @ as an operator to convert a comptime-known string to an identifier
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+	- Use @ as an operator to convert a comptime-known string to an identifier
+
+Do I need impredicativity or can I just use rank-2 polymorphism?
+	- I think rank-2 is decidable.
+	- If impredicativity, use bidirectional typechecking with Quick Look.
+Equirecursive or isorecursive?
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