solidity/test/libsolidity/semanticTests/storage/packed_storage_overflow.sol

contract C {
    uint16 x = 0x1234;
    uint16 a = 0xffff;
    uint16 b;

    function f() public returns (uint256, uint256, uint256, uint256) {
        unchecked { a++; }
        uint256 c = b;
        delete b;
        unchecked { a -= 2; }
        return (x, c, b, a);
    }
}

// ----
// f() -> 0x1234, 0x0, 0x0, 0xfffe