contract C {
    uint x;
    function f() public {
        require(x + 1 > x);
        ++x;
    }
    function g() public {
        uint y = x;
        f();
        assert(y == (x - 1));
    }
}

contract C {
    uint x;
    function f() public {
        require(x + 1 > x);
        ++x;
    }
    function g() public {
        require(x > 10);
        uint y = x;
        uint i = 0;
        for (; i < 10; ++i)
            f();
        assert(y == (x - 10));
    }
}

contract A {
    int public s;
    B b;

    constructor() public { s=0; b = new B(this);}

    function f() public {
        require(s+1>s);
        bool status;
        bytes memory result;
        int s0=s;
        (status, result) = address(b).call.gas(10000)(abi.encodePacked(bytes4(keccak256("g()"))));
        assert(s0==s);
        incs();
        assert(s>0);
    }

    function getBs() public view returns(int) {return b.s();}
    function incs() public {s+=1;}
}

contract B{
    int public s;
    A a;
    constructor(A _a) public {s=0; a=_a;}
    function g() external {
        s+=1;
        a.incs();
        assert(false);
    }
}