Lots of exceptions: "element: DocComment; restoredElement: null; signature: 'docComment;method#read#0'; file: ScalaFile:..."

Can you attach full IDEA log?

Best regards,
Alexander Podkhalyuzin.

Log file is attached.
Here is a log as isplayed in IDE Fatal Error dialog:

element: DocComment; restoredElement: null; signature: 'docComment;method#setFont#0'; file: ScalaFile:EditorView.scala; restored again: null; restore produces same results: true; trace:
Provider 'com.intellij.codeInsight.folding.impl.XmlElementSignatureProvider'. Restoring parent by signature 'method#setFont#0'...
Provider 'com.intellij.codeInsight.folding.impl.XmlElementSignatureProvider'. Restoring target element by signature 'method#setFont#0'. Parent: ScalaFile:EditorView.scala, same as the given parent: true
Restored parent by signature 'method#setFont#0': null
Provider 'com.intellij.codeInsight.folding.impl.JavaElementSignatureProvider'. Restoring parent by signature 'method#setFont#0'...
Provider 'com.intellij.codeInsight.folding.impl.JavaElementSignatureProvider'. Restoring target element by signature 'method#setFont#0'. Parent: ScalaFile:EditorView.scala, same as the given parent: true
Restored parent by signature 'method#setFont#0': null
Provider 'com.intellij.codeInsight.folding.impl.PsiNamesElementSignatureProvider'. Restoring parent by signature 'method#setFont#0'...
Provider 'com.intellij.codeInsight.folding.impl.PsiNamesElementSignatureProvider'. Restoring target element by signature 'method#setFont#0'. Parent: ScalaFile:EditorView.scala, same as the given parent: true
Stopping 'com.intellij.codeInsight.folding.impl.PsiNamesElementSignatureProvider' provider because given signature doesn't have expected type - can work with 'n' but got 'method'
Restored parent by signature 'method#setFont#0': null
Provider 'com.intellij.codeInsight.folding.impl.OffsetsElementSignatureProvider'. Restoring parent by signature 'method#setFont#0'...
Provider 'com.intellij.codeInsight.folding.impl.OffsetsElementSignatureProvider'. Restoring target element by signature 'method#setFont#0'. Parent: ScalaFile:EditorView.scala, same as the given parent: true
Stopping 'com.intellij.codeInsight.folding.impl.OffsetsElementSignatureProvider' provider because given signature doesn't have expected type - can work with 'e' but got 'method'
Restored parent by signature 'method#setFont#0': null

java.lang.Throwable
    at com.intellij.openapi.diagnostic.Logger.error(Logger.java:54)
    at com.intellij.codeInsight.folding.impl.DocumentFoldingInfo.writeExternal(DocumentFoldingInfo.java:185)
    at com.intellij.codeInsight.folding.impl.CodeFoldingManagerImpl.writeFoldingState(CodeFoldingManagerImpl.java:305)
    at com.intellij.openapi.fileEditor.impl.text.PsiAwareTextEditorProvider.writeState(PsiAwareTextEditorProvider.java:80)
    at com.intellij.openapi.fileEditor.impl.HistoryEntry.writeExternal(HistoryEntry.java:131)
    at com.intellij.openapi.fileEditor.impl.EditorsSplitters.a(EditorsSplitters.java:259)
    at com.intellij.openapi.fileEditor.impl.EditorsSplitters.a(EditorsSplitters.java:248)
    at com.intellij.openapi.fileEditor.impl.EditorsSplitters.a(EditorsSplitters.java:224)
    at com.intellij.openapi.fileEditor.impl.EditorsSplitters.writeExternal(EditorsSplitters.java:199)
    at com.intellij.openapi.fileEditor.impl.FileEditorManagerImpl.writeExternal(FileEditorManagerImpl.java:1308)
    at com.intellij.tasks.context.OpenEditorsContextProvider.saveContext(OpenEditorsContextProvider.java:49)
    at com.intellij.tasks.context.WorkingContextManager.saveContext(WorkingContextManager.java:91)
    at com.intellij.tasks.context.WorkingContextManager.saveContext(WorkingContextManager.java:129)
    at com.intellij.tasks.context.WorkingContextManager.saveContext(WorkingContextManager.java:108)
    at com.intellij.tasks.impl.TaskCheckinHandlerFactory$1$1.run(TaskCheckinHandlerFactory.java:62)
    at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:251)
    at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:701)
    at java.awt.EventQueue.access$000(EventQueue.java:102)
    at java.awt.EventQueue$3.run(EventQueue.java:662)
    at java.awt.EventQueue$3.run(EventQueue.java:660)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:76)
    at java.awt.EventQueue.dispatchEvent(EventQueue.java:671)
    at com.intellij.ide.IdeEventQueue.e(IdeEventQueue.java:699)
    at com.intellij.ide.IdeEventQueue._dispatchEvent(IdeEventQueue.java:538)
    at com.intellij.ide.IdeEventQueue.b(IdeEventQueue.java:420)
    at com.intellij.ide.IdeEventQueue.dispatchEvent(IdeEventQueue.java:378)
    at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:244)
    at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:163)
    at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:151)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:147)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:139)
    at java.awt.EventDispatchThread.run(EventDispatchThread.java:97)

Can you create a ticket with file text on which this exception reproducible? (you can try to minimize your file, we also do not need any dependencies of this file, just text): http://youtrack.jetbrains.com/issues/SCL

Best regards,
Alexander Podkahlyzuin.

Created: http://youtrack.jetbrains.com/issue/SCL-4469