From af3320c7f7dc5a048d42135886393679ba61f6d0 Mon Sep 17 00:00:00 2001
From: Mario Rugiero <mrugiero@gmail.com>
Date: Thu, 5 Oct 2023 11:27:27 -0300
Subject: [PATCH] Impl Zero

---
 crates/stark-felt/src/arbitrary_proptest.rs |  1 +
 crates/stark-felt/src/lib.rs                | 21 ++++++++++++---------
 2 files changed, 13 insertions(+), 9 deletions(-)

diff --git a/crates/stark-felt/src/arbitrary_proptest.rs b/crates/stark-felt/src/arbitrary_proptest.rs
index 28ae9e5..49ea020 100644
--- a/crates/stark-felt/src/arbitrary_proptest.rs
+++ b/crates/stark-felt/src/arbitrary_proptest.rs
@@ -1,4 +1,5 @@
 use lambdaworks_math::{field::element::FieldElement, unsigned_integer::element::UnsignedInteger};
+use num_traits::Zero;
 use proptest::prelude::*;
 
 use crate::Felt;
diff --git a/crates/stark-felt/src/lib.rs b/crates/stark-felt/src/lib.rs
index 2bff8bc..e321ec1 100644
--- a/crates/stark-felt/src/lib.rs
+++ b/crates/stark-felt/src/lib.rs
@@ -3,7 +3,7 @@
 use core::ops::{Add, Neg};
 
 use bitvec::array::BitArray;
-use num_traits::{FromPrimitive, ToPrimitive};
+use num_traits::{FromPrimitive, ToPrimitive, Zero};
 
 #[cfg(test)]
 mod arbitrary_proptest;
@@ -130,10 +130,6 @@ impl Felt {
         BitArray::new(limbs)
     }
 
-    /// Checks if `self` is equal to [Felt::ZERO].
-    pub fn is_zero(&self) -> bool {
-        *self == Felt::ZERO
-    }
     /// Finite field division.
     pub fn field_div(&self, rhs: &NonZeroFelt) -> Self {
         Self(self.0 / rhs.0)
@@ -381,6 +377,16 @@ impl ToPrimitive for Felt {
     }
 }
 
+impl Zero for Felt {
+    fn is_zero(&self) -> bool {
+        *self == Felt::ZERO
+    }
+
+    fn zero() -> Felt {
+        Felt::ZERO
+    }
+}
+
 impl Add<&Felt> for u64 {
     type Output = Option<u64>;
 
@@ -822,10 +828,7 @@ mod errors {
 
 #[cfg(test)]
 mod test {
-    use super::{
-        alloc::{format, string::String, vec::Vec},
-        Felt, FieldElement, NonZeroFelt,
-    };
+    use super::*;
     use crate::arbitrary_proptest::nonzero_felt;
     use core::ops::Shl;
     use proptest::prelude::*;