Check EVC addr

TODO

@@ -9,8 +9,6 @@
 * ConstantSum: incorporate price multipliers in quote methods
 * natspec
 * permit2 instead of regular approval: measure gas savings
-* in constructor, check the two vaults have the correct EVC() return value
-  * maybe even that they were created by the EVK factory?
 ? a really small swap could fail because deposit() results in 0 shares, which EVK fails on. call convertToShares() first? Seems like overkill
 ? pause guardian
 ? how should aggregators find instances

src/MaglevBase.sol

@@ -27,6 +27,7 @@ abstract contract MaglevBase is IMaglevBase, EVCUtil {
     error BadFee();
     error InsufficientReserves();
     error InsufficientCash();
+    error DifferentEVC();
 
     modifier nonReentrant() {
         require(locked == 0, Locked());
@@ -48,6 +49,10 @@ abstract contract MaglevBase is IMaglevBase, EVCUtil {
     constructor(BaseParams memory params) EVCUtil(params.evc) {
         require(params.fee < 1e18, BadFee());
 
+        address vault0Evc = IEVault(params.vault0).EVC();
+        require(vault0Evc == IEVault(params.vault1).EVC(), DifferentEVC());
+        require(vault0Evc == params.evc, DifferentEVC());
+
         vault0 = params.vault0;
         vault1 = params.vault1;
         asset0 = IEVault(vault0).asset();

test/EulerSwap.t.sol

@@ -8,7 +8,7 @@ import {TestERC20} from "evk-test/unit/evault/EVaultTestBase.t.sol";
 import {IEVault} from "evk/EVault/IEVault.sol";
 import {MaglevTestBase} from "./MaglevTestBase.t.sol";
 
-import {MaglevEulerSwap as Maglev} from "../src/MaglevEulerSwap.sol";
+import {MaglevEulerSwap as Maglev, MaglevBase} from "../src/MaglevEulerSwap.sol";
 
 contract EulerSwapTest is MaglevTestBase {
     Maglev public maglev;
@@ -41,6 +41,23 @@ contract EulerSwapTest is MaglevTestBase {
         maglev.configure();
     }
 
+    function test_different_EVC() public {
+        vm.expectRevert(MaglevBase.DifferentEVC.selector);
+
+        new Maglev(
+            MaglevBase.BaseParams({
+                evc: address(makeAddr("RANDOM_EVC")),
+                vault0: address(eTST),
+                vault1: address(eTST2),
+                myAccount: holder,
+                debtLimit0: 50e18,
+                debtLimit1: 50e18,
+                fee: 0
+            }),
+            Maglev.EulerSwapParams({priceX: 1e18, priceY: 1e18, concentrationX: 4e18, concentrationY: 0.85e18})
+        );
+    }
+
     function test_basicSwap_exactIn() public monotonicHolderNAV {
         uint256 amountIn = 1e18;
         uint256 amountOut = maglev.quoteExactInput(address(assetTST), address(assetTST2), amountIn);