2019-02-06 10:12:02 +00:00
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pragma experimental SMTChecker;
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contract C
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{
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function f(uint8 x) public pure returns (uint8) {
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2020-12-16 17:32:34 +00:00
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uint8 y;
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unchecked { y = x + 255; }
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2019-02-06 10:12:02 +00:00
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require(y >= x);
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x = 255;
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2020-12-16 17:32:34 +00:00
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unchecked { y = x + 1; }
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2019-02-06 10:12:02 +00:00
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assert(y == 0);
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y = x + 255;
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assert(y == 254);
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return y;
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}
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}
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// ----
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2020-12-29 08:39:45 +00:00
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// Warning 4984: (218-225): CHC: Overflow (resulting value larger than 255) happens here.\nCounterexample:\n\nx = 255\n = 0\n\nTransaction trace:\nC.constructor()\nC.f(0)
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