pragma experimental SMTChecker;

contract C
{
	function f(uint8 x) public pure returns (uint) {
		x = 0;
		uint8 y;
		unchecked { y = x - 1; }
		assert(y == 255);
		unchecked { y = x - 255; }
		assert(y == 1);
		return y;
	}
}
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