add Default constraint
@@ -117,7 +117,7 @@ pub struct CollectionIndex<K, V, T, R>
where
K: ExchangeData,
V: ExchangeData,
- T: Lattice+ExchangeData,
+ T: Lattice+ExchangeData+Default,
R: Monoid+Mul<Output = R>+ExchangeData,
{
/// A trace of type (K, ()), used to count extensions for each prefix.
@@ -185,7 +185,7 @@ pub struct CollectionExtender<K, V, T, R, P, F>
where
K: ExchangeData,
V: ExchangeData,
- T: Lattice+ExchangeData,
+ T: Lattice+ExchangeData+Default,
R: Monoid+Mul<Output = R>+ExchangeData,
F: Fn(&P)->K,
{
