Xcode 9 code completion and highlighting not working

xcode xcode9
Nic Hubbard picture Nic Hubbard · Sep 25, 2017 · Viewed 9k times · Source

I have seen many threads about this online, but not for Xcode 9. For some reason code completion and syntax highlighting is no longer working. Last week it was fine.

Using the GM build.

Anyone have this issue or know how to resolve it? A restart of Xcode and my computer did not help.

Answer

gpdawson picture gpdawson · Oct 3, 2017

In Finder I navigated to user->Library->Developer->Xcode->DerivedData and deleted the subfolder of the project in question. After next build of the project the syntax highlighting and code completion returned.

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