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class LoopTargets {
method M() returns (y) {
y := 0
while (y < 100) { y := y + 1 }
assert y == 0 // error (139)
}
method N() returns (t: LoopTargets)
lockchange t
{
t := new LoopTargets
share t
acquire t
var s := true
while (s)
lockchange t
{
release t // error: loop invariant does not say holds(t) (252)
s := false
}
}
method P() {
var t := new LoopTargets
share t
acquire t
var s := true
while (s)
invariant acc(t.mu) && waitlevel == t.mu
lockchange t
{
release t // error: loop invariant does not say holds(t) (414)
acquire t
s := false
}
release t
}
method Q() {
var t := new LoopTargets
share t
acquire t
var s := true
while (s)
invariant rd(t.mu)
invariant holds(t) && waitlevel == t.mu
lockchange t
{
release t
acquire t
s := false
}
assert holds(t) // there we are
release t
}
}
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