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// RUN: %dafny /print:"%t.print" "%s" > "%t"
// RUN: %diff "%s.expect" "%t"
class Ref<A> {
var val: A;
}
method Nice(n: int) {
var f : int -> int := x => x;
var i := new Ref<int>;
i.val := 0;
while (i.val < n)
invariant forall u :: f.requires(u);
invariant forall u :: f.reads(u) == {};
invariant forall u :: f(u) == u + i.val;
{
i.val := i.val + 1;
f := x => f(x) + 1;
}
}
method OneShot(n: int) {
var f : int -> int := x => x;
var i := 0;
while (i < n)
invariant forall u :: f.requires(u);
invariant forall u :: f(u) == u + i;
{
i := i + 1;
f := x reads f.reads(x) -> f(x) + 1;
}
}
method HeapQuant(n: int) {
var f : int -> int := x => x;
var i := new Ref<int>;
ghost var r := 0;
i.val := 0;
while (i.val < n)
invariant forall u {:heapQuantifier} :: f.requires(u);
invariant forall u {:heapQuantifier} :: f.reads(u) == {};
invariant r == i.val;
invariant forall u {:heapQuantifier} :: f(u) == u + r;
{
i.val, r := i.val + 1, r + 1;
f := x => f(x) + 1;
}
}
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