library合约中，函数限定符不能为public

[JacksonRGB]

pragma solidity 0.6.10;

library SafeSub {
    
    function sub(uint x, uint y) public pure returns(uint) {
        require(x >= y);
        return x - y;
    }
    
}

contract Test {
    function sub(uint x, uint y) public returns(uint) {
        return SafeSub.sub(x, y);
    }
}

调用sub函数时返回错误0x16，因为bincode中存在地址占位符，ide不能自动替换

临时解决：修改SafeSub中sub函数的限定符为internal