问题
I have a project with 2 targets, both targets share more than 99% codes and was written in Swift 3.
When XCode 9 is available, one of the targets is being scanned, the codes and the target's "Build Settings" are all updated for Swift 4. Sadly, I just found out that another target is still marked as Swift 3.2 syntax.
I would like to update the second target to Swift 4 by XCode, however, the second target is marked as Swift 3.2 syntax but the codes are Swift 4 already, it is not compilable and thus automatic update to Swift 4 by XCode is not worked.
Since both targets share most of the codes, I do not need XCode to help me scan or convert the codes automatically, I would like to upgrade the whole project to Swift 4 instead. I have updated the "Swift Language Version" in Build Settings of the second target to Swift 4.0 manually. Is there any other project settings which I should take care too?
Thanks
回答1:
I have updated the "Swift Language Version" in Build Settings of the second target to Swift 4.0 manually
Check the Swift 3 @objc inference is set to off.
Other than that, you are good to go.
来源：https://stackoverflow.com/questions/46401856/xcode-upgrade-to-swift-4-manually