Fix silent integer truncations (#71)

lightclient-circuits/src/gadget/crypto/sha256_wide.rs

@@ -51,7 +51,7 @@ impl<'a, F: Field> HashInstructions<F> for Sha256ChipWide<'a, F> {
         let binary_input: HashInput<u8> = HashInput::Single(
             assigned_bytes
                 .iter()
-                .map(|av| av.value().get_lower_32() as u8)
+                .map(|av| u8::try_from(av.value().get_lower_32()).expect("truncated"))
                 .collect_vec()
                 .into(),
         );

lightclient-circuits/src/util/circuit.rs

@@ -73,7 +73,7 @@ impl Halo2ConfigPinning for Eth2ConfigPinning {
     }
 
     fn degree(&self) -> u32 {
-        self.params.k as u32
+        u32::try_from(self.params.k).expect("k is too large for u32")
     }
 }
 

test-utils/src/lib.rs

@@ -44,7 +44,8 @@ pub fn get_initial_sync_committee_poseidon<const EPOCHS_PER_SYNC_COMMITTEE_PERIO
         poseidon_committee_commitment_from_uncompressed(&pubkeys_uncompressed, LIMB_BITS);
     let committee_poseidon =
         ethers::prelude::U256::from_little_endian(&committee_poseidon.to_bytes());
-    let sync_period = (bootstrap.header.beacon.slot as usize) / EPOCHS_PER_SYNC_COMMITTEE_PERIOD;
+    let sync_period = (usize::try_from(bootstrap.header.beacon.slot).expect("truncated"))
+        / EPOCHS_PER_SYNC_COMMITTEE_PERIOD;
     Ok((sync_period, committee_poseidon))
 }