original.name="MultiAssign_Invalid_1"
======
>>> main.whiley
type nat is (int x) where x >= 0

function f(int x, int y) -> (int xp, int yp):
    return y,x

function min(nat a, int b) -> int:
    a,b = f(a,b)
    if x > y:
        return y
    else:
        return x

public export method test() :
    int x = min(0,-1)

---
E407 main.whiley 8,7
E407 main.whiley 8,11
E407 main.whiley 9,15
E407 main.whiley 11,15