Validate implicitly unwrapped optionals

[jpsim]

Implicitly unwrapped optionals should not be used.

[throughnothing]

+1 for this

[frederic-adda]

I don't agree, they are quite useful

[BrianDoig]

If crashing is ok in your product, then yes they are useful. If management yells at you if you have crashes then they aren't ok...

[throughnothing]

@frederic-adda It would just be an option to turn on. You'd be free to keep it off, of course.

[jpsim]

To clarify, implicitly unwrapped optionals certainly have their place, but using them superfluously is certainly a code smell that might indicate that the code should be refactored to avoid them.

If a SwiftLint rule would apply 100% of the time, it should go in the Swift compiler. A linter exists to help identify code smells, not things that are incorrect 100% of the time. That's the language's job.

[marcelofabri]

Fixed on #1362 💥