feat(cast): add support for beacon proxies in cast impl

crates/cast/bin/args.rs

@@ -606,7 +606,8 @@ pub enum CastSubcommand {
         formula_id: String,
     },
 
-    /// Fetch the EIP-1967 implementation account
+    /// Fetch the EIP-1967 implementation for a contract
+    /// Can read from the implementation slot or the beacon slot.
     #[command(visible_alias = "impl")]
     Implementation {
         /// The block height to query at.
@@ -615,7 +616,13 @@ pub enum CastSubcommand {
         #[arg(long, short = 'B')]
         block: Option<BlockId>,
 
-        /// The address to get the nonce for.
+        /// Fetch the implementation from the beacon slot.
+        ///
+        /// If not specified, the implementation slot is used.
+        #[arg(long)]
+        beacon: bool,
+
+        /// The address for which the implementation will be fetched.
         #[arg(value_parser = NameOrAddress::from_str)]
         who: NameOrAddress,
 
@@ -632,7 +639,7 @@ pub enum CastSubcommand {
         #[arg(long, short = 'B')]
         block: Option<BlockId>,
 
-        /// The address to get the nonce for.
+        /// The address from which the admin account will be fetched.
         #[arg(value_parser = NameOrAddress::from_str)]
         who: NameOrAddress,
 

crates/cast/bin/main.rs

@@ -425,11 +425,11 @@ async fn main_args(args: CastArgs) -> Result<()> {
             let id = stdin::unwrap_line(id)?;
             sh_println!("{}", foundry_common::erc7201(&id))?;
         }
-        CastSubcommand::Implementation { block, who, rpc } => {
+        CastSubcommand::Implementation { block, beacon, who, rpc } => {
             let config = Config::from(&rpc);
             let provider = utils::get_provider(&config)?;
             let who = who.resolve(&provider).await?;
-            sh_println!("{}", Cast::new(provider).implementation(who, block).await?)?;
+            sh_println!("{}", Cast::new(provider).implementation(who, beacon, block).await?)?;
         }
         CastSubcommand::Admin { block, who, rpc } => {
             let config = Config::from(&rpc);

crates/cast/src/lib.rs

@@ -571,14 +571,33 @@ where
     ///     ProviderBuilder::<_, _, AnyNetwork>::default().on_builtin("http://localhost:8545").await?;
     /// let cast = Cast::new(provider);
     /// let addr = Address::from_str("0x7eD52863829AB99354F3a0503A622e82AcD5F7d3")?;
-    /// let implementation = cast.implementation(addr, None).await?;
+    /// let implementation = cast.implementation(addr, false, None).await?;
     /// println!("{}", implementation);
     /// # Ok(())
     /// # }
     /// ```
-    pub async fn implementation(&self, who: Address, block: Option<BlockId>) -> Result<String> {
-        let slot =
-            B256::from_str("0x360894a13ba1a3210667c828492db98dca3e2076cc3735a920a3ca505d382bbc")?;
+    pub async fn implementation(
+        &self,
+        who: Address,
+        is_beacon: bool,
+        block: Option<BlockId>,
+    ) -> Result<String> {
+        let slot = match is_beacon {
+            true => {
+                // Use the beacon slot : bytes32(uint256(keccak256('eip1967.proxy.beacon')) - 1)
+                B256::from_str(
+                    "0xa3f0ad74e5423aebfd80d3ef4346578335a9a72aeaee59ff6cb3582b35133d50",
+                )?
+            }
+            false => {
+                // Use the implementation slot :
+                // bytes32(uint256(keccak256('eip1967.proxy.implementation')) - 1)
+                B256::from_str(
+                    "0x360894a13ba1a3210667c828492db98dca3e2076cc3735a920a3ca505d382bbc",
+                )?
+            }
+        };
+
         let value = self
             .provider
             .get_storage_at(who, slot.into())

crates/cast/tests/cli/main.rs

@@ -627,6 +627,42 @@ casttest!(rlp, |_prj, cmd| {
 "#]]);
 });
 
+// test that `cast impl` works correctly for both the implementation slot and the beacon slot
+casttest!(impl_slot, |_prj, cmd| {
+    let eth_rpc_url = next_http_rpc_endpoint();
+
+    // Call `cast impl` for the implementation slot (AAVE Proxy)
+    cmd.args([
+        "impl",
+        "0x4965f6FA20fE9728deCf5165016fc338a5a85aBF",
+        "--rpc-url",
+        eth_rpc_url.as_str(),
+    ])
+    .assert_success()
+    .stdout_eq(str![[r#"
+0xb61306c8eb34a2104d9eb8d84f1bb1001067fa4b
+
+"#]]);
+});
+
+casttest!(impl_slot_beacon, |_prj, cmd| {
+    let eth_rpc_url = next_http_rpc_endpoint();
+
+    // Call `cast impl` for the beacon slot
+    cmd.args([
+        "impl",
+        "0xc63d9f0040d35f328274312fc8771a986fc4ba86",
+        "--beacon",
+        "--rpc-url",
+        eth_rpc_url.as_str(),
+    ])
+    .assert_success()
+    .stdout_eq(str![[r#"
+0xa748ae65ba11606492a9c57effa0d4b7be551ec2
+
+"#]]);
+});
+
 // test for cast_rpc without arguments
 casttest!(rpc_no_args, |_prj, cmd| {
     let eth_rpc_url = next_http_rpc_endpoint();