Unfortunately, I can't give you steps to reproduce an exception because I didn't experience it myself. It was sent to Intellij team via built-in exceptions reported.
Appeared in IDEA Community 173.2290
java.lang.NullPointerException
java.lang.RuntimeException: java.lang.NullPointerException
at com.intellij.ide.util.treeView.AbstractTreeUi$54$1.perform(AbstractTreeUi.java:3430)
at com.intellij.ide.util.treeView.TreeRunnable.run(TreeRunnable.java:36)
at com.intellij.ide.util.treeView.AbstractTreeBuilder$2.perform(AbstractTreeBuilder.java:445)
at com.intellij.ide.util.treeView.TreeRunnable.run(TreeRunnable.java:36)
at com.intellij.openapi.application.impl.ApplicationImpl.runReadAction(ApplicationImpl.java:923)
at com.intellij.ide.util.treeView.AbstractTreeBuilder.runBackgroundLoading(AbstractTreeBuilder.java:442)
at com.intellij.ide.util.treeView.AbstractTreeUi$54.perform(AbstractTreeUi.java:3385)
at com.intellij.ide.util.treeView.TreeRunnable.run(TreeRunnable.java:36)
at com.intellij.openapi.progress.impl.CoreProgressManager.lambda$runProcess$1(CoreProgressManager.java:171)
at com.intellij.openapi.progress.impl.CoreProgressManager.registerIndicatorAndRun(CoreProgressManager.java:548)
at com.intellij.openapi.progress.impl.CoreProgressManager.executeProcessUnderProgress(CoreProgressManager.java:493)
at com.intellij.openapi.progress.impl.ProgressManagerImpl.executeProcessUnderProgress(ProgressManagerImpl.java:94)
at com.intellij.openapi.progress.impl.CoreProgressManager.runProcess(CoreProgressManager.java:158)
at com.intellij.ide.util.treeView.AbstractTreeUi$55.perform(AbstractTreeUi.java:3447)
at com.intellij.ide.util.treeView.TreeRunnable.run(TreeRunnable.java:36)
at com.intellij.ide.util.treeView.AbstractTreeUi.lambda$new$0(AbstractTreeUi.java:98)
at com.intellij.util.concurrency.QueueProcessor.lambda$null$0(QueueProcessor.java:93)
at com.intellij.util.concurrency.QueueProcessor.runSafely(QueueProcessor.java:246)
at com.intellij.util.concurrency.QueueProcessor.lambda$wrappingProcessor$1(QueueProcessor.java:93)
at com.intellij.util.concurrency.QueueProcessor.lambda$null$3(QueueProcessor.java:226)
at com.intellij.util.concurrency.QueueProcessor.runSafely(QueueProcessor.java:246)
at com.intellij.util.concurrency.QueueProcessor.lambda$startProcessing$4(QueueProcessor.java:226)
at com.intellij.openapi.application.impl.ApplicationImpl$1.run(ApplicationImpl.java:327)
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
at java.util.concurrent.FutureTask.run(FutureTask.java:266)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:745)
Caused by: java.lang.NullPointerException
at lv.kid.vermut.intellij.yaml.editor.NeonStructureViewElement.getLocationString(NeonStructureViewElement.java:87)
at com.intellij.ide.projectView.PresentationData.updateFrom(PresentationData.java:186)
at com.intellij.ide.util.treeView.smartTree.TreeElementWrapper.update(TreeElementWrapper.java:41)
at com.intellij.ide.util.treeView.PresentableNodeDescriptor.getUpdatedPresentation(PresentableNodeDescriptor.java:88)
at com.intellij.ide.util.treeView.PresentableNodeDescriptor.update(PresentableNodeDescriptor.java:41)
at com.intellij.ide.util.treeView.AbstractTreeBuilder.updateNodeDescriptor(AbstractTreeBuilder.java:545)
at com.intellij.ide.util.treeView.AbstractTreeUi$22.perform(AbstractTreeUi.java:935)
at com.intellij.ide.util.treeView.TreeRunnable.run(TreeRunnable.java:36)
at com.intellij.ide.util.treeView.AbstractTreeUi.execute(AbstractTreeUi.java:1856)
at com.intellij.ide.util.treeView.AbstractTreeUi.update(AbstractTreeUi.java:931)
at com.intellij.ide.util.treeView.AbstractTreeUi.update(AbstractTreeUi.java:852)
at com.intellij.ide.util.treeView.AbstractTreeUi.access$1600(AbstractTreeUi.java:64)
at com.intellij.ide.util.treeView.AbstractTreeUi$15.perform(AbstractTreeUi.java:704)
at com.intellij.ide.util.treeView.TreeRunnable.run(TreeRunnable.java:36)
at com.intellij.ide.util.treeView.AbstractTreeUi.execute(AbstractTreeUi.java:1856)
at com.intellij.ide.util.treeView.AbstractTreeUi.access$2600(AbstractTreeUi.java:64)
at com.intellij.ide.util.treeView.AbstractTreeUi$54$1.perform(AbstractTreeUi.java:3394)
... 27 more
Unfortunately, I can't give you steps to reproduce an exception because I didn't experience it myself. It was sent to Intellij team via built-in exceptions reported.
Appeared in IDEA Community 173.2290