solidity/test/libsolidity/smtCheckerTests/overflow/overflow_sum_signed.sol

pragma experimental SMTChecker;

contract C
{
	function f(int8 x) public pure returns (int8) {
		x = 127;
		int8 y = x + 1;
		assert(y == -128);
		y = x + 127;
		assert(y == -2);
		x = -127;
		y = x + -127;
		assert(y == 2);
	}
}
// ----
// Warning 6321: (87-91): Unnamed return variable can remain unassigned. Add an explicit return with value to all non-reverting code paths or name the variable.
// Warning 4984: (117-122): CHC: Overflow (resulting value larger than 127) happens here.\nCounterexample:\n\nx = 127\n = 0\n\nTransaction trace:\nconstructor()\nf(0)
// Warning 4984: (151-158): CHC: Overflow (resulting value larger than 127) happens here.\nCounterexample:\n\nx = 127\n = 0\n\nTransaction trace:\nconstructor()\nf(0)
// Warning 3944: (197-205): CHC: Underflow (resulting value less than -128) happens here.\nCounterexample:\n\nx = (- 127)\n = 0\n\nTransaction trace:\nconstructor()\nf(0)