[Different level of error asserting in swift and corresponding result]

DifferentLevelOfErrorAssertingInSwift.txt

                        debug   release   release
function                -Onone  -O       -Ounchecked
assert()                YES     NO        NO
assertionFailure()      YES     NO        NO**
precondition()          YES     YES       NO
preconditionFailure()   YES     YES       YES**
fatalError()*           YES     YES       YES

– assert: checking your own code for internal errors
– precondition: for checking that your clients have given you valid arguments.