original.name="Switch_Invalid_4"
======
>>> main.whiley
function f(int x) -> int:
    switch x:
        case 1:
            return 0
        case 1:
            return 1
        default:
            return 0
---
E313 main.whiley 5,13
=====
>>> main.whiley 3:4
        case 0:
>>> main.whiley 9

public export method test():
    assume f(0) == 0
    assume f(1) == 1
    assume f(2) == 0
---