chore: add lints to protobuf (#1845)

Lior banned `as` repo-wide, unless absolutely necessary.

Changes: use try_from instead of relying on implicit truncation due of
`u128 as u64`.

Co-Authored-By: Gilad Chase <gilad@starkware.com>

crates/papyrus_protobuf/Cargo.toml

@@ -37,3 +37,6 @@ protoc-prebuilt.workspace = true
 [package.metadata.cargo-machete]
 # The `rand` and `rand_chacha` crates are used in the `testing` feature, which is optional.
 ignored = ["rand", "rand_chacha"]
+
+[lints]
+workspace = true

crates/papyrus_protobuf/src/converters/common.rs

@@ -53,7 +53,11 @@ impl From<starknet_api::core::ContractAddress> for protobuf::Address {
 
 impl From<u128> for protobuf::Uint128 {
     fn from(value: u128) -> Self {
-        Self { high: (value >> 64) as u64, low: value as u64 }
+        Self {
+            high: u64::try_from(value >> 64).expect("64-bit shift of u128 is a u64."),
+            low: u64::try_from(value & u128::from(u64::MAX))
+                .expect("Bottom 64 bits of u128 are a u64."),
+        }
     }
 }
 

crates/papyrus_protobuf/src/converters/consensus.rs

@@ -114,7 +114,7 @@ impl From<Vote> for protobuf::Vote {
         };
 
         protobuf::Vote {
-            vote_type: vote_type as i32,
+            vote_type: i32::from(vote_type),
             height: value.height,
             round: value.round,
             block_hash: value.block_hash.map(|hash| hash.0.into()),