contract C { function f(uint8 x) public pure returns (uint8) { uint8 y; unchecked { y = x + 255; } require(y >= x); x = 255; unchecked { y = x + 1; } assert(y == 0); y = x + 255; assert(y == 254); return y; } } // ==== // SMTEngine: all // ---- // Warning 4984: (185-192): CHC: Overflow (resulting value larger than 255) happens here. // Info 1391: CHC: 2 verification condition(s) proved safe! Enable the model checker option "show proved safe" to see all of them.