original.name="Function_Valid_6"
======
>>> main.whiley
type fr5nat is (int x) where x >= 0

function g(fr5nat[] xs) -> fr5nat[]:
    fr5nat[] ys = [0; |xs|]
    int i = 0
    while i < |xs| where i >= 0 && |xs| == |ys|:
        if xs[i] > 1:
            ys[i] = xs[i]
        i = i + 1
    return ys

function f(fr5nat[] x) -> int[]:
    return x

public export method test() :
    fr5nat[] ys = [1, 2, 3]
    assume f(g(ys)) == [0, 2, 3]

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