[swift-evolution] [Draft] Abolish IUO type

Brent Royal-Gordon brent at architechies.com
Fri Mar 18 01:53:09 CDT 2016

> (Come to think of it, is there a cost to converting between `T?` and `T!`, or do they get optimized into the same thing?)

I can't imagine there would be. @autounwrapped (or whatever) is a purely compile-time thing which tells the compiler to automatically insert a `!` operator if it will make the expression typecheck. Other than that compile-time behavior, `!` is an exact synonym for `?`.

Brent Royal-Gordon

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