How do I restore indexing functionality? (Xcode) - xcode

Question

One of my projects (containing over 200 files in pure Swift) has just recently started interfering with the indexing process. The indexing process freezes midway and then stops abruptly, causing SourceKitService to crash.
I simply cannot find the faulty code; because there appears to be none!
My code compiles just fine (without a single warning!) - and yet it fails to be indexed. Initially, I thought it to be an Xcode 7.2 issue and so upgraded to the latest beta (7.3); however the issue still persists. I cannot revert back to my old code because too much work will be undone, and I can't spot a particular file to blame. The crash report is here.
To clarify, Xcode itself does not crash, only the indexing process (and SourceKitService as a consequence).
Any ideas on how to go about fixing this?

Answer 1

Remove "xcuserdata" from .xcodeproj (right click on .xcodeproj > select Show Package Contents. This should solve the problem.

Answer 2

If I'm reading properly,
the problem comes from this part of the process:
Thread 8 Crashed:
0 com.apple.SourceKitService 0x000000010450d9fc swift::TypeBase::getDesugaredType() + 12
1 com.apple.SourceKitService 0x00000001043bccbe (anonymous namespace)::DeclChecker::checkDynamicSelfReturn(swift::FuncDecl*, swift::TypeRepr*, unsigned int) + 478
2 com.apple.SourceKitService 0x00000001043b7c08 (anonymous namespace)::DeclChecker::visitFuncDecl(swift::FuncDecl*) + 1432
3 com.apple.SourceKitService 0x00000001043acc0d (anonymous namespace)::DeclChecker::visit(swift::Decl*) + 2733
4 com.apple.SourceKitService 0x00000001043a7ea7 swift::TypeChecker::validateDecl(swift::ValueDecl*, bool) + 727
5 com.apple.SourceKitService 0x00000001043b6426 (anonymous namespace)::DeclChecker::visitSubscriptDecl(swift::SubscriptDecl*) + 1478
6 com.apple.SourceKitService 0x00000001043acbdd (anonymous namespace)::DeclChecker::visit(swift::Decl*) + 2685
7 com.apple.SourceKitService 0x00000001043a7ea7 swift::TypeChecker::validateDecl(swift::ValueDecl*, bool) + 727
8 com.apple.SourceKitService 0x00000001044fc003 swift::DeclContext::lookupQualified(swift::Type, swift::DeclName, unsigned int, swift::LazyResolver*, llvm::SmallVectorImpl<swift::ValueDecl*>&) const + 3075
9 com.apple.SourceKitService 0x00000001043c7a7c swift::TypeChecker::lookupMember(swift::DeclContext*, swift::Type, swift::DeclName, swift::OptionSet<swift::NameLookupFlags, unsigned int>) + 556
10 com.apple.SourceKitService 0x00000001043d51b7 (anonymous namespace)::ConformanceChecker::lookupValueWitnesses(swift::ValueDecl*, bool*) + 359
11 com.apple.SourceKitService 0x00000001043d11a1 (anonymous namespace)::ConformanceChecker::resolveWitnessViaLookup(swift::ValueDecl*) + 401
12 com.apple.SourceKitService 0x00000001043ce86f swift::TypeChecker::checkConformance(swift::NormalProtocolConformance*) + 2255
13 com.apple.SourceKitService 0x000000010438011b typeCheckFunctionsAndExternalDecls(swift::TypeChecker&) + 1099
14 com.apple.SourceKitService 0x00000001043809e5 swift::performTypeChecking(swift::SourceFile&, swift::TopLevelContext&, swift::OptionSet<swift::TypeCheckingFlags, unsigned int>, unsigned int) + 1781
15 com.apple.SourceKitService 0x0000000103fa40c2 swift::CompilerInstance::performSema() + 4738
16 com.apple.SourceKitService 0x0000000103e9a836 SourceKit::SwiftLangSupport::indexSource(llvm::StringRef, SourceKit::IndexingConsumer&, llvm::ArrayRef<char const*>, llvm::StringRef) + 4262
17 com.apple.SourceKitService 0x0000000103eb086a void SourceKit::WorkQueue::DispatchData::callAndDelete<handleRequestImpl(void*, std::__1::function<void (void*)>)::$_2>(void*) + 2170
18 libdispatch.dylib 0x00007fff9b7de33f _dispatch_client_callout + 8
19 libdispatch.dylib 0x00007fff9b7ec03a _dispatch_block_invoke + 474
20 com.apple.SourceKitService 0x00000001056afbbf executeBlock(void*) + 15
21 com.apple.SourceKitService 0x0000000103f3e58d ExecuteOnThread_Dispatch(void*) + 13
22 libsystem_pthread.dylib 0x00007fff8be14c13 _pthread_body + 131
23 libsystem_pthread.dylib 0x00007fff8be14b90 _pthread_start + 168
24 libsystem_pthread.dylib 0x00007fff8be12375 thread_start + 13
which leads us to :
https://github.com/apple/swift/pull/932/files
20days + ago
So I guess it's a known issue.
However I don't know what is causing it. I'm pretty sure it's a swift code style that is not well supported yet.
I also found your crash in this Crash test project:
https://github.com/practicalswift/swift-compiler-crashes
If you look into it, you might find the precise case that triggers one of those crashes:
✓ 28197 swift typebase getdesugaredtype
✓ 28200 swift typebase getdesugaredtype
✓ 28203 swift typebase getdesugaredtype