pragma experimental SMTChecker; contract C { uint x; modifier m { require(x > 0); _; // Fails because of overflow behavior. assert(x > 1); } function f() m public { assert(x > 0); x = x + 1; } function g(uint _x) public { x = _x; } } // ---- // Warning 4984: (203-208): CHC: Overflow (resulting value larger than 2**256 - 1) happens here.\nCounterexample:\nx = 115792089237316195423570985008687907853269984665640564039457584007913129639935\n\n\n\nTransaction trace:\nconstructor()\nState: x = 0\ng(115792089237316195423570985008687907853269984665640564039457584007913129639935)\nState: x = 115792089237316195423570985008687907853269984665640564039457584007913129639935\nf() // Warning 6328: (136-149): CHC: Assertion violation happens here.\nCounterexample:\nx = 0\n\n\n\nTransaction trace:\nconstructor()\nState: x = 0\ng(115792089237316195423570985008687907853269984665640564039457584007913129639935)\nState: x = 115792089237316195423570985008687907853269984665640564039457584007913129639935\nf()