original.name="While_Valid_58"
======
>>> main.whiley
function double(int n) -> (int m):
assume n >= 0
int i = 0
m = 0
while i < n where i >= 0 && i <= n && m==2*i:
i = i+1
m = m+2
assert m == 2*n
return m
public export method test():
assume double(0) == 0
assume double(1) == 2
assume double(2) == 4
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