[SOLVED] Rules for type check in Swift builds?

Rules for type check in Swift builds?

I’ve wanted to speed up my build times, so one of the steps was using Other Swift Flags and

-Xfrontend -warn-long-function-bodies=100
-Xfrontend -warn-long-expression-type-checking=100

But I’m not really sure how type checks work. For example, here’s a simple func for creating random CGFloat. Type check for it is over 200ms

static func randomColorValue() -> CGFloat {
    return CGFloat(Int.random(in: 0...255))/255.0
}

But on changing to something like this

  static func randomColorValue() -> CGFloat {
         let rnd    = Int.random(in: 0...255)
         let frnd   = CGFloat(rnd)
         let result = frnd/255.0

         return result
     }

or like this

static func randomColorValue() -> CGFloat {
     let rnd    : Int     = Int.random(in: 0...255)
     let frnd   : CGFloat = CGFloat(rnd)
     let result : CGFloat = frnd/255.0

     return result
 }

type check is still over 200ms.

What's wrong here? Is there any set of rules and best practices for dealing with build times? My Mac is a bit older (2012), maybe that's the problem?

EDIT:

After turning off -warn-long-function-bodies problematic line appeared, and that is

CGFloat(rnd)

It appears that casting Int to Float, Double or CGFloat shows slowing down of 150ms.

Solution

Note that warn-long-function-bodies is unsupported (it was added as an experimental flag). If you remove it, I find that the expression time is often reported as twice as fast, which makes be believe that using the two measurements together is causing interference. Measurement takes time, too. warn-long-expression is a supported option.