Murisi/allowed conversion negation

masp_primitives/src/convert.rs

@@ -16,7 +16,7 @@ use std::collections::BTreeMap;
 use std::{
     io::{self, Write},
     iter::Sum,
-    ops::{Add, AddAssign, Sub, SubAssign},
+    ops::{Add, AddAssign, Neg, Sub, SubAssign},
 };
 
 #[derive(Clone, Debug, PartialEq, Eq)]
@@ -196,6 +196,17 @@ impl SubAssign for AllowedConversion {
     }
 }
 
+impl Neg for AllowedConversion {
+    type Output = Self;
+
+    fn neg(self) -> Self {
+        Self {
+            assets: -self.assets,
+            generator: -self.generator,
+        }
+    }
+}
+
 impl Sum for AllowedConversion {
     fn sum<I: Iterator<Item = Self>>(iter: I) -> Self {
         iter.fold(AllowedConversion::from(ValueSum::zero()), Add::add)

masp_primitives/src/transaction/components/amount.rs

@@ -440,15 +440,26 @@ where
     type Output = ValueSum<Unit, <Lhs as CheckedMul<Rhs>>::Output>;
 
     fn mul(self, rhs: Rhs) -> Self::Output {
+        self.checked_mul(rhs).expect("overflow detected")
+    }
+}
+
+impl<Unit, Lhs, Rhs> CheckedMul<Rhs> for ValueSum<Unit, Lhs>
+where
+    Unit: Hash + Ord + BorshSerialize + BorshDeserialize + Clone,
+    Lhs: BorshSerialize + BorshDeserialize + PartialEq + Eq + Copy + Default + CheckedMul<Rhs>,
+    Rhs: Copy,
+    <Lhs as CheckedMul<Rhs>>::Output: Default + BorshSerialize + BorshDeserialize + Eq,
+{
+    type Output = ValueSum<Unit, <Lhs as CheckedMul<Rhs>>::Output>;
+
+    fn checked_mul(self, rhs: Rhs) -> Option<Self::Output> {
         let mut comps = BTreeMap::new();
         for (atype, amount) in self.0.iter() {
-            comps.insert(
-                atype.clone(),
-                amount.checked_mul(rhs).expect("overflow detected"),
-            );
+            comps.insert(atype.clone(), amount.checked_mul(rhs)?);
         }
         comps.retain(|_, v| *v != <Lhs as CheckedMul<Rhs>>::Output::default());
-        ValueSum(comps)
+        Some(ValueSum(comps))
     }
 }