interface I {
	function ext() external;
}

contract C {
	function f(I _i) public {
		uint x = address(this).balance;
		_i.ext();
		assert(address(this).balance == x); // should fail
		assert(address(this).balance >= x); // should hold
	}
}
// ====
// SMTEngine: all
// SMTIgnoreOS: macos
// ----
// Warning 6328: (131-165): CHC: Assertion violation happens here.
// Info 1391: CHC: 1 verification condition(s) proved safe! Enable the model checker option "show proved safe" to see all of them.