diff --git a/fixed_wide/src/narrow.rs b/fixed_wide/src/narrow.rs
index 4ba82a9..f48483b 100644
--- a/fixed_wide/src/narrow.rs
+++ b/fixed_wide/src/narrow.rs
@@ -15,6 +15,7 @@ pub trait TryNarrow{
 mod tests {
 	use super::*;
 
+	//TODO: use num_traits to do a blanket implementation (self<T::MIN as U)
 	impl TryNarrow for i16{
 		type Output=i8;
 		fn try_narrow(self)->Result<Self::Output,NarrowError>{