Call into EntryPoint's receive fallback via deposit() for gas savings (#16)

Author: mdehoog

src/Paymaster.sol

@@ -98,6 +98,7 @@ contract Paymaster is BasePaymaster {
     }
 
     receive() external payable {
-        deposit();
+        (bool callSuccess, ) = payable(address(entryPoint)).call{value: msg.value}("");
+        require(callSuccess, "Deposit failed");
     }
-}
+}

test/Paymaster.t.sol

@@ -123,6 +123,13 @@ contract PaymasterTest is Test {
         entrypoint.simulateValidation(userOp);
     }
 
+    function test_receive() public {
+        assertEq(0, entrypoint.balanceOf(address(paymaster)));
+        (bool callSuccess, ) = address(paymaster).call{value: 1 ether}("");
+        require(callSuccess, "Receive failed");
+        assertEq(1 ether, entrypoint.balanceOf(address(paymaster)));
+    }
+
     function createUserOp() public view returns (UserOperation memory) {
         UserOperation memory userOp;
         userOp.sender = address(account);