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java.util.ConcurrentModificationException
	at java.util.HashMap$HashIterator.nextEntry(HashMap.java:793)
	at java.util.HashMap$EntryIterator.next(HashMap.java:834)
	at java.util.HashMap$EntryIterator.next(HashMap.java:832)
	at org.jetbrains.plugins.ruby.ruby.lang.psi.dataFlow.reachingDefs.RReachingDefsDfaInstance.fun(RReachingDefsDfaInstance.java:37)
	at org.jetbrains.plugins.ruby.ruby.lang.psi.dataFlow.reachingDefs.RReachingDefsDfaInstance.fun(RReachingDefsDfaInstance.java:25)
	at org.jetbrains.plugins.ruby.ruby.lang.psi.dataFlow.DFAEngine.performDFA(DFAEngine.java:95)
	at org.jetbrains.plugins.ruby.ruby.codeInsight.resolve.scope.impl.ScopeImpl.computeScopeVariables(ScopeImpl.java:65)
	at org.jetbrains.plugins.ruby.ruby.codeInsight.resolve.scope.impl.ScopeImpl.getVisibleVariable(ScopeImpl.java:46)
	at org.jetbrains.plugins.ruby.ruby.codeInsight.resolve.scope.ScopeUtil.findScopeVariableForIdentifier(ScopeUtil.java:44)
	at org.jetbrains.plugins.ruby.ruby.lang.psi.impl.variables.RIdentifierImpl.getScopeVariable(RIdentifierImpl.java:79)
	at org.jetbrains.plugins.ruby.ruby.codeInsight.references.psi.RIdentifierReference.isReferenceTo(RIdentifierReference.java:58)
	at org.jetbrains.plugins.ruby.ruby.lang.search.RubyCodeOccurenceProcessor.execute(RubyCodeOccurenceProcessor.java:46)
	at com.intellij.psi.impl.search.LowLevelSearchUtil.processTreeUp(LowLevelSearchUtil.java:92)
	at com.intellij.psi.impl.search.LowLevelSearchUtil.processElementsContainingWordInElement(LowLevelSearchUtil.java:122)
	at com.intellij.psi.impl.search.PsiSearchHelperImpl$4$1$1.run(PsiSearchHelperImpl.java:233)
	at com.intellij.openapi.application.impl.ApplicationImpl.runReadAction(ApplicationImpl.java:674)
	at com.intellij.psi.impl.search.PsiSearchHelperImpl$4$1.run(PsiSearchHelperImpl.java:225)
	at com.intellij.openapi.progress.impl.ProgressManagerImpl.executeProcessUnderProgress(ProgressManagerImpl.java:154)
	at com.intellij.psi.impl.search.PsiSearchHelperImpl$4.process(PsiSearchHelperImpl.java:223)
	at com.intellij.psi.impl.search.PsiSearchHelperImpl$4.process(PsiSearchHelperImpl.java:219)
	at com.intellij.concurrency.JobUtil$1.run(JobUtil.java:44)
	at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:441)
	at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303)
	at java.util.concurrent.FutureTask.run(FutureTask.java:138)
	at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
	at java.lang.Thread.run(Thread.java:619)