exit status: 1 with stderr:
<stdin>:4:12: error: cannot convert value of type 'Int' to expected argument type 'String' f(a: 0, b: 0, x: 0, y: 0) ^ <stdin>:4:18: error: cannot convert value of type 'Int' to expected argument type 'String' f(a: 0, b: 0, x: 0, y: 0) ^ <stdin>:4:24: error: cannot convert value of type 'Int' to expected argument type 'String' f(a: 0, b: 0, x: 0, y: 0) ^