feat: add checked_write_int for int256 (#415)

* add checked_write_signed for int256

* rename checked_write_signed to checked_write_int

Author: astermirac1e

src/StdStorage.sol

@@ -239,6 +239,10 @@ library stdStorage {
         checked_write(self, bytes32(amt));
     }
 
+    function checked_write_int(StdStorage storage self, int256 val) internal {
+        checked_write(self, bytes32(uint256(val)));
+    }
+
     function checked_write(StdStorage storage self, bool write) internal {
         bytes32 t;
         /// @solidity memory-safe-assembly

test/StdStorage.t.sol

@@ -31,6 +31,16 @@ contract StdStorageTest is Test {
         assertEq(test.exists(), 100);
     }
 
+    function testStorageCheckedWriteSignedIntegerHidden() public {
+        stdstore.target(address(test)).sig(test.hidden.selector).checked_write_int(-100);
+        assertEq(int256(uint256(test.hidden())), -100);
+    }
+
+    function testStorageCheckedWriteSignedIntegerObvious() public {
+        stdstore.target(address(test)).sig(test.tG.selector).checked_write_int(-100);
+        assertEq(test.tG(), -100);
+    }
+
     function testStorageMapStructA() public {
         uint256 slot =
             stdstore.target(address(test)).sig(test.map_struct.selector).with_key(address(this)).depth(0).find();