fix(rpc): clone EthSigner trait objects with generic tx request (#23050)

crates/rpc/rpc-eth-api/src/helpers/signer.rs

@@ -31,4 +31,46 @@ pub trait EthSigner<T, TxReq = TransactionRequest>: Send + Sync + DynClone {
     fn sign_typed_data(&self, address: Address, payload: &TypedData) -> Result<Signature>;
 }
 
-dyn_clone::clone_trait_object!(<T> EthSigner<T>);
+dyn_clone::clone_trait_object!(<T, TxReq> EthSigner<T, TxReq>);
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[derive(Clone)]
+    struct MockSigner;
+
+    struct MockSignedTx;
+    struct MockTxReq;
+
+    #[async_trait::async_trait]
+    impl EthSigner<MockSignedTx, MockTxReq> for MockSigner {
+        fn accounts(&self) -> Vec<Address> {
+            Vec::new()
+        }
+
+        async fn sign(&self, _address: Address, _message: &[u8]) -> Result<Signature> {
+            Err(SignError::NoAccount)
+        }
+
+        async fn sign_transaction(
+            &self,
+            _request: MockTxReq,
+            _address: &Address,
+        ) -> Result<MockSignedTx> {
+            Err(SignError::NoAccount)
+        }
+
+        fn sign_typed_data(&self, _address: Address, _payload: &TypedData) -> Result<Signature> {
+            Err(SignError::NoAccount)
+        }
+    }
+
+    #[test]
+    fn clones_trait_object_with_custom_tx_request_type() {
+        let signer: Box<dyn EthSigner<MockSignedTx, MockTxReq>> = Box::new(MockSigner);
+        let cloned: Box<dyn EthSigner<MockSignedTx, MockTxReq>> = dyn_clone::clone_box(&*signer);
+
+        assert!(cloned.accounts().is_empty());
+    }
+}