original.name="IntAdd_Valid_1"
======
>>> main.whiley
function swap2(int x, int y) -> (int r, int s)
ensures true:
assume x == 10
assume y == 11
x = (2 * x) + y
y = x - y
x = x - y
assert x == 11 && y == 2 * 10
return x, y
public export method test():
//
(int a, int b) = swap2(10,11)
//
assume a == 11 && b == 2*10
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