V_B data for issue #507

data/V_B-Q.md

@@ -0,0 +1,20 @@
+### 1. depositETH double work
+
+There is a `depositETH` function in a `Vault` smart contract. The function accepts ether, deposit it to WETH contract and transfer wrapped tokens to the sender. Later the funds will be transferred as a ERC20 token from users account to smart contract. 
+
+The alternative approach can be just accepting the ether, that which will reduce the cost of depositing a lot and clarify the logic.
+
+### 2. symbol == "rY2K" check
+
+The Vault smart contract has the following check in the `beforeWithdraw` function:
+
+```solidity
+if (
+    keccak256(abi.encodePacked(symbol)) ==
+    keccak256(abi.encodePacked("rY2K"))
+) {
+    ...
+}
+```
+
+It makes no sense to do this check every time the function is called, it's better to do this check once in the constructor and store the result as an `immutable` variable.