original.name="UnionType_Valid_25"
======
>>> main.whiley

type nintarr is bool[]|int[]

method main(nintarr xs)
requires (xs is int[]) ==> |xs| > 0:
    //
    if xs is int[]:
        xs[0] = 0
    //
    assume xs == [0,2,3]

public export method test() :
    main([1,2,3])
    

---