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// Example to test candidate annotations on loops
function {:existential true} Assert(): bool;
function {:existential true} b1():bool;
function {:existential true} b2():bool;
function {:existential true} b3():bool;
function {:existential true} b4():bool;
function {:existential true} b5():bool;
function {:existential true} b6():bool;
function {:existential true} b7():bool;
var x: int;
var y: int;
procedure foo()
modifies x;
modifies y;
ensures (b4() || x == 0);
ensures (b5() || y == 10);
ensures (b6() || x == 10);
ensures (b7() || y == 11);
{
x := 10;
y := 0;
goto Head;
Head:
//loop invariants
assert (b1() || x < 0);
assert (b2() || x >= 0);
assert (b3() || x + y == 10);
goto Body, Exit;
Body:
assume x > 0;
x := x - 1;
y := y + 1;
goto Head;
Exit:
assume !(x > 0);
return;
}
// expected assigment: Assert -> false, b1->true,b2->false,b3->false,b4->false, b5->false, b6->true,b7->true
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