Xcode 6.3 code completion too slow

Question

I've just updated Xcode to version 6.3. I'm working on a project in Swift with some imported Objective C code. I also use Cocoapods.

I had the same issue with the Xcode 6.3 beta. I've seen and tried all other StackOverflow answers with no luck.

So far I've tried to:

• Delete ~/Library/Developer/Xcode/DerivedData and ~/Library/Caches/com.apple.dt.Xcode with Xcode and/or Mac restart.

• Uninstall Spotify.

• Not use the "+" concatenation operator.

• Set deployment's target to 8.1.

I should mention that Objective C code autocompletes fast and that before indexing Swift code too. Esc button for popup suggestions works with the same delay.

Answer 1

Setting Whole Module Optimization to Yes is a workaround in my project.

In my case, the project has 5 modules, named here A, B, C, D and E, where the dependency is diagramed A -> B -> C -> D, and each of A to D refers E. With Xcode 6.3 and 6.3.1, it is fine to compile modules E and D, but it takes longer to compile C, and much longer to compile B and A, like 10 mins. After I change the project setting, it takes less than a min to compile all the modules. It looks faster than compilation with Xcode 6.2.

References:

• Slow test file compilation in Swift 1.2, Xcode 6.3.1
• https://devforums.apple.com/message/1128702#1128702

Answer 2

Try to clear project Derived Data, after update.
Window - Projects - YourProject - Derived Data - Delete...
In my case code completion is working better after update.