Possible fix for NPE:

java.lang.NullPointerException
	at com.intellij.codeInsight.daemon.impl.analysis.HighlightNamesUtil.getMethodDeclarationTextRange(HighlightNamesUtil.java:258)
	at com.intellij.codeInsight.daemon.impl.analysis.GenericsHighlightUtil.checkSameErasureNotSubSignatureOrSameClass(GenericsHighlightUtil.java:611)
	at com.intellij.codeInsight.daemon.impl.analysis.GenericsHighlightUtil.checkSameErasureNotSubSignatureInner(GenericsHighlightUtil.java:540)
	at com.intellij.codeInsight.daemon.impl.analysis.GenericsHighlightUtil.checkSameErasureNotSubSignatureInner(GenericsHighlightUtil.java:549)
	at com.intellij.codeInsight.daemon.impl.analysis.GenericsHighlightUtil.checkOverrideEquivalentMethods(GenericsHighlightUtil.java:474)
	at com.intellij.codeInsight.daemon.impl.analysis.HighlightVisitorImpl.visitModifierList(HighlightVisitorImpl.java:788)
	at com.intellij.psi.impl.source.PsiModifierListImpl.accept(PsiModifierListImpl.java:287)
	at com.intellij.codeInsight.daemon.impl.analysis.HighlightVisitorImpl.visit(HighlightVisitorImpl.java:107)
	at com.intellij.codeInsight.daemon.impl.GeneralHighlightingPass$10.run(GeneralHighlightingPass.java:644)
	at com.intellij.codeInsight.daemon.impl.GeneralHighlightingPass.analyzeByVisitors(GeneralHighlightingPass.java:757)
	at com.intellij.codeInsight.daemon.impl.GeneralHighlightingPass.access$3500(GeneralHighlightingPass.java:83)
	at com.intellij.codeInsight.daemon.impl.GeneralHighlightingPass$12.run(GeneralHighlightingPass.java:763)
	at com.intellij.codeInsight.daemon.impl.DefaultHighlightVisitor.analyze(DefaultHighlightVisitor.java:87)
	at com.intellij.codeInsight.daemon.impl.GeneralHighlightingPass.analyzeByVisitors(GeneralHighlightingPass.java:760)
	at com.intellij.codeInsight.daemon.impl.GeneralHighlightingPass.access$3500(GeneralHighlightingPass.java:83)
	at com.intellij.codeInsight.daemon.impl.GeneralHighlightingPass$12.run(GeneralHighlightingPass.java:763)
	at com.intellij.codeInsight.daemon.impl.RefCountHolder.analyze(RefCountHolder.java:295)
	at com.intellij.codeInsight.daemon.impl.analysis.HighlightVisitorImpl.analyze(HighlightVisitorImpl.java:137)
	at com.intellij.codeInsight.daemon.impl.GeneralHighlightingPass.analyzeByVisitors(GeneralHighlightingPass.java:760)
	at com.intellij.codeInsight.daemon.impl.GeneralHighlightingPass.collectHighlights(GeneralHighlightingPass.java:717)
	at com.intellij.codeInsight.daemon.impl.GeneralHighlightingPass.collectInformationWithProgress(GeneralHighlightingPass.java:208)
	at com.intellij.codeInsight.daemon.impl.ProgressableTextEditorHighlightingPass.doCollectInformation(ProgressableTextEditorHighlightingPass.java:58)
	at com.intellij.codeHighlighting.TextEditorHighlightingPass.collectInformation(TextEditorHighlightingPass.java:62)
	at com.intellij.codeInsight.daemon.impl.PassExecutorService$ScheduledPass$1$1.run(PassExecutorService.java:357)
	at com.intellij.openapi.application.impl.ApplicationImpl.tryRunReadAction(ApplicationImpl.java:1182)
	at com.intellij.codeInsight.daemon.impl.PassExecutorService$ScheduledPass$1.run(PassExecutorService.java:348)
	at com.intellij.openapi.progress.impl.ProgressManagerImpl.executeProcessUnderProgress(ProgressManagerImpl.java:226)
	at com.intellij.codeInsight.daemon.impl.PassExecutorService$ScheduledPass.doRun(PassExecutorService.java:345)
	at com.intellij.codeInsight.daemon.impl.PassExecutorService$ScheduledPass.run(PassExecutorService.java:321)
	at com.intellij.concurrency.JobLauncherImpl$3.call(JobLauncherImpl.java:145)
	at com.intellij.concurrency.JobLauncherImpl$3.call(JobLauncherImpl.java:142)
	at java.util.concurrent.FutureTask.run(FutureTask.java:262)
	at com.intellij.concurrency.PrioritizedFutureTask.access$101(PrioritizedFutureTask.java:31)
	at com.intellij.concurrency.PrioritizedFutureTask$1.run(PrioritizedFutureTask.java:70)
	at com.intellij.concurrency.PrioritizedFutureTask.run(PrioritizedFutureTask.java:113)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
	at java.lang.Thread.run(Thread.java:744)