diff --git a/crates/evm/fuzz/src/strategies/int.rs b/crates/evm/fuzz/src/strategies/int.rs
index 91197a4f6e731..3d882ae903b62 100644
--- a/crates/evm/fuzz/src/strategies/int.rs
+++ b/crates/evm/fuzz/src/strategies/int.rs
@@ -184,7 +184,7 @@ impl IntStrategy {
 
         // init I256 from 2 randoms
         let mut inner: [u64; 4] = [0; 4];
-        let mask64 = (1 << 65) - 1;
+        let mask64: u128 = (1u128 << 64) - 1;
         inner[0] = (lower & mask64) as u64;
         inner[1] = (lower >> 64) as u64;
         inner[2] = (higher & mask64) as u64;
diff --git a/crates/evm/fuzz/src/strategies/uint.rs b/crates/evm/fuzz/src/strategies/uint.rs
index b31da09803f98..b448cd982bd51 100644
--- a/crates/evm/fuzz/src/strategies/uint.rs
+++ b/crates/evm/fuzz/src/strategies/uint.rs
@@ -158,7 +158,7 @@ impl UintStrategy {
 
         // init U256 from 2 randoms
         let mut inner: [u64; 4] = [0; 4];
-        let mask64 = (1 << 65) - 1;
+        let mask64: u128 = (1u128 << 64) - 1;
         inner[0] = (lower & mask64) as u64;
         inner[1] = (lower >> 64) as u64;
         inner[2] = (higher & mask64) as u64;