and this is the stack

UndefinedObject(Object)>>doesNotUnderstand: #doSemanticAnalysisIn: [ aCompiledMethod parseTree doSemanticAnalysisIn: aCompiledMethod methodClass ] in ASTCache>>at: in Block: [ aCompiledMethod parseTree... [ self at: key put: aBlock value ] in ASTCache(Dictionary)>>at:ifAbsentPut: in Block: [ self at: key put: aBlock value ] ASTCache(Dictionary)>>at:ifAbsent: ASTCache(Dictionary)>>at:ifAbsentPut: ASTCache>>at: ASTCache class>>at: CompiledMethod>>ast [ :arg1 | arg1 shouldStyle ifTrue: [ self selectedMethod ast acceptVisitor: (arg1 style: self sourceTextModel) ] ] in NautilusUI(AbstractNautilusUI)>>addIconStyle in Block: [ :arg1 | ... Array(SequenceableCollection)>>do: AbstractIconStyler class(Class)>>subclassesDo: NautilusUI(AbstractNautilusUI)>>addIconStyle NautilusUI(AbstractNautilusUI)>>resetIconStyle Nautilus>>package:class:protocol:method: NautilusUI>>forceSelectedMethod: NautilusUI>>selectedMethod: MethodWidget>>selectedMethod: MethodWidget>>selectedMethodIndex: FTPluggableIconListMorphAdaptor>>selectionChangedUpdateIndex: FTPluggableIconListMorphAdaptor>>selectionChanged: MessageSend>>value: MessageSend>>cull: MessageSend>>cull:cull: [ action cull: anAnnouncement cull: announcer ] in AnnouncementSubscription>>deliver: in Block: [ action cull: anAnnouncement cull: announcer ] BlockClosure>>on:do: BlockClosure>>on:fork: AnnouncementSubscription>>deliver: [ subscription deliver: anAnnouncement ] in SubscriptionRegistry>>deliver:to:startingAt: in Block: [ subscription deliver: anAnnouncement ] BlockClosure>>ifCurtailed: SubscriptionRegistry>>deliver:to:startingAt: