is there any micro improvement to use explicit typ...

# announcements

[pp.amorim]

is there any micro improvement to use explicit types in relation to compilation time?
In Swift you can get faster compilation time if you set explicit types, I am not sure how Kotlin deals with it.

[erluxman]

I think Its true in every programming language? Not 100% sure though

[gildor]

In theory it should be faster, but I never saw any evidences that explicit type somehow helps with compilation time.
I wouldn’t recommend to use this approach.
Better to spend time on optimisation that really can help, such as modularisation of your project or even just profiling your build

[pp.amorim]

Thank you. I am not having problems with the compile time, I am just curious.

[pp.amorim]

in Swift, if you don't set the type of your array, the compiler gets super slow and sometimes crash

[pp.amorim]

you can't do let d = [foo, bar, fee] with many items. The compiler never finishes the compilation.
You need to do:
var d: [Int] = []; d += foo; d += bar; d += fee

[erluxman]

Really?

[pp.amorim]

https://medium.com/@johnsundell/improving-swift-compile-times-ee1d52fb9bd

[pp.amorim]

Read about Collection literals

[pp.amorim]

String concatenation also suffer this problem, this is hilarious: https://stackoverflow.com/a/48916182/2430555
"Expression was too complex to be solved in reasonable time"

[pp.amorim]

I did this once and the compiler running on a CI took 30 minutes to compile a single line. 🧌

[gildor]

Wow

[gildor]

It has to do with type inference. Each time you use the + operator, Swift has to search through all of the possible overloads for + and infer which version of + you are using

is this because of explicit imports are not required by default?

[pp.amorim]

probably, this could be solved with caching...