library L { function add(uint x, uint y) internal pure returns (uint) { require(x < 1000); require(y < 1000); return x + y; } } contract C { function f(uint x) public pure { uint y = L.add(x, 999); assert(y < 1000); } } // ==== // SMTEngine: all // ---- // Warning 6328: (212-228): CHC: Assertion violation happens here.\nCounterexample:\n\nx = 1\ny = 1000\n\nTransaction trace:\nC.constructor()\nC.f(1)\n L.add(1, 999) -- internal call