original.name="Coercion_Valid_8"
======
>>> main.whiley
type Expr is int | Expr[]

function f(Expr x) -> int:
    if x is Expr[]:
        return |x|
    else:
        return x

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

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