original.name="While_Valid_51"
======
>>> main.whiley
function f(int[] xs) -> (bool r)
ensures r ==> all { j in 0..|xs| | xs[j] != 0}:
//
int i = 0
//
while i < |xs|
where i >= 0
where all { j in 0..i | xs[j] != 0}:
//
if xs[i] == 0:
return false
i = i + 1
//
return true
public export method test():
assume f([1,2,3,4])
assume !f([0,2,4,3])
assume f([1])
---