original.name="UnionType_Valid_19"
======
>>> main.whiley


type utr12nat is int

type intList is utr12nat | int[]

type tupper is {int op, intList il}

function f(tupper y) -> int:
    return y.op

public export method test() :
    tupper x = {op: 1, il: 1}
    assume f(x) == 1

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