unable to get stub builder for com.intellij.openapi.fileTypes.UnknownFileType

[cvette]

java.lang.Throwable: unable to get stub builder for com.intellij.openapi.fileTypes.UnknownFileType@3caa945c, , stubBindingRoot = PsiBinaryFileImpl, languages = [], fileTypes = [UNKNOWN], files = [PsiBinaryFileImpl], roots = []
	at com.intellij.openapi.diagnostic.Logger.error(Logger.java:145)
	at com.intellij.psi.stubs.StubProcessingHelperBase.handleNonPsiStubs(StubProcessingHelperBase.java:112)
	at com.intellij.psi.stubs.StubProcessingHelperBase.processStubsInFile(StubProcessingHelperBase.java:63)
	at com.intellij.psi.stubs.StubIndexImpl$2.process(StubIndexImpl.java:290)
	at com.intellij.psi.stubs.StubIndexImpl$StubIdListContainerAction.perform(StubIndexImpl.java:602)
	at com.intellij.psi.stubs.StubIndexImpl$StubIdListContainerAction.perform(StubIndexImpl.java:590)
	at com.intellij.util.indexing.ValueContainer.forEach(ValueContainer.java:62)
	at com.intellij.psi.stubs.StubIndexImpl.lambda$null$0(StubIndexImpl.java:314)
	at com.intellij.util.ConcurrencyUtil.withLock(ConcurrencyUtil.java:245)
	at com.intellij.psi.stubs.StubIndexImpl.lambda$null$1(StubIndexImpl.java:312)
	at com.intellij.util.indexing.FileBasedIndexImpl.disableUpToDateCheckIn(FileBasedIndexImpl.java:671)
	at com.intellij.psi.stubs.StubIndexImpl.lambda$doProcessStubs$2(StubIndexImpl.java:311)
	at com.intellij.util.indexing.IndexAccessValidator.validate(IndexAccessValidator.java:43)
	at com.intellij.psi.stubs.StubIndexImpl.doProcessStubs(StubIndexImpl.java:309)
	at com.intellij.psi.stubs.StubIndexImpl.processElements(StubIndexImpl.java:281)
	at com.intellij.psi.stubs.StubIndex.getElements(StubIndex.java:121)
	at com.intellij.psi.stubs.StubIndex.getElements(StubIndex.java:109)
	at de.vette.idea.neos.lang.fusion.completion.PrototypeProvider.addCompletions(PrototypeProvider.java:44)
	at com.intellij.codeInsight.completion.CompletionProvider.addCompletionVariants(CompletionProvider.java:36)
	at com.intellij.codeInsight.completion.CompletionContributor.fillCompletionVariants(CompletionContributor.java:161)
	at com.intellij.codeInsight.completion.CompletionService.getVariantsFromContributors(CompletionService.java:90)
	at com.intellij.codeInsight.completion.CompletionResultSet.runRemainingContributors(CompletionResultSet.java:149)
	at com.intellij.codeInsight.completion.CompletionResultSet.runRemainingContributors(CompletionResultSet.java:142)
	at com.intellij.codeInsight.template.impl.LiveTemplateCompletionContributor$1.addCompletions(LiveTemplateCompletionContributor.java:77)
	at com.intellij.codeInsight.completion.CompletionProvider.addCompletionVariants(CompletionProvider.java:36)
	at com.intellij.codeInsight.completion.CompletionContributor.fillCompletionVariants(CompletionContributor.java:161)
	at com.intellij.codeInsight.completion.CompletionService.getVariantsFromContributors(CompletionService.java:90)
	at com.intellij.codeInsight.completion.CompletionService.performCompletion(CompletionService.java:120)
	at com.intellij.codeInsight.completion.impl.CompletionServiceImpl.performCompletion(CompletionServiceImpl.java:60)
	at com.intellij.codeInsight.completion.CompletionProgressIndicator.calculateItems(CompletionProgressIndicator.java:828)
	at com.intellij.codeInsight.completion.CompletionProgressIndicator.runContributors(CompletionProgressIndicator.java:813)
	at com.intellij.codeInsight.completion.CodeCompletionHandlerBase.lambda$null$2(CodeCompletionHandlerBase.java:280)
	at com.intellij.openapi.application.impl.ApplicationImpl.tryRunReadAction(ApplicationImpl.java:1166)
	at com.intellij.codeInsight.completion.AsyncCompletion.tryReadOrCancel(CompletionThreading.java:170)
	at com.intellij.codeInsight.completion.CodeCompletionHandlerBase.lambda$doComplete$3(CodeCompletionHandlerBase.java:277)
	at com.intellij.codeInsight.completion.AsyncCompletion.lambda$null$0(CompletionThreading.java:95)
	at com.intellij.openapi.progress.impl.CoreProgressManager.lambda$runProcess$2(CoreProgressManager.java:164)
	at com.intellij.openapi.progress.impl.CoreProgressManager.registerIndicatorAndRun(CoreProgressManager.java:586)
	at com.intellij.openapi.progress.impl.CoreProgressManager.executeProcessUnderProgress(CoreProgressManager.java:532)
	at com.intellij.openapi.progress.impl.ProgressManagerImpl.executeProcessUnderProgress(ProgressManagerImpl.java:86)
	at com.intellij.openapi.progress.impl.CoreProgressManager.runProcess(CoreProgressManager.java:151)
	at com.intellij.codeInsight.completion.AsyncCompletion.lambda$startThread$1(CompletionThreading.java:91)
	at com.intellij.openapi.application.impl.ApplicationImpl$1.run(ApplicationImpl.java:311)
	at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
	at java.util.concurrent.FutureTask.run(FutureTask.java:266)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
	at java.lang.Thread.run(Thread.java:748)