This is one of those "how the hell Xcode didn't have this already?" type of things. A very welcome change, I personally don't do much iOS development but got those EXC_BAD_INSTRUCTION errors in past and they were always very misleading to me.
Apple tends to re-think the current technology and implements their ideal solution. This takes longer but avoids the duck tape approach I've seen in various iterations of Visual Studio. As a concrete example the refactoring tools in Xcode9 work for both C++ (for the first time!), Objective-C and Swift using the same framework.
Best of all the API to write your own refactoring tools has been carefully designed, and there have been some high quality external contributions already to the refactoring tools.
Xcode 9.2 might be great, but 9.1 doesn't seem to take any interest in the most urgent problems of 9.0, i.e everything breaks as SourceKit grinds relentlessly in the background chewing up more and more memory (it reached 18 gigs physical ram on my 16 gig MacBook somehow!).
First it forgets how to find symbols, or refactor, then text entry slows so much until I have to wait a few seconds every time I type just to see what I typed, finally the editor just freezes for lengthy periods. That's just the most prominent problems.
Fortunately restart fixes these problems, but not most others.
Set "defaults write com.apple.dt.Xcode IDESourceKitServiceLogLevel 3" and SourceKit will write a log to /tmp with all the details of what it is doing while indexing. A lot of people find they have header hygiene problems or module problems that happen to work while building in certain configurations but aren't actually correct, resulting in missing modules or broken headers from the indexer's point of view.
Dealing with C/C++ headers, includes, modules, et al is part of the reason a lot of editors never bother with trying to offer complicated refactoring, autocomplete, etc. It is far from trivial no matter what build system you are using.
If you file a bug report and attach your project someone on the indexer team will personally take a look.