NullPointerException

[FroMage]

Just got this one:

java.lang.NullPointerException
    at org.eclipse.core.runtime.Path.isPrefixOf(Path.java:632)
    at com.redhat.ceylon.eclipse.imp.parser.CeylonParseController.getSourceFolder(CeylonParseController.java:419)
    at com.redhat.ceylon.eclipse.imp.parser.CeylonParseController.parse(CeylonParseController.java:170)
    at org.eclipse.imp.parser.ParseControllerBase.parse(ParseControllerBase.java:71)
    at org.eclipse.imp.model.internal.CompilationUnitRef.getAST(CompilationUnitRef.java:151)
    at com.redhat.ceylon.eclipse.imp.quickfix.CeylonQuickFixAssistant.addProposals(CeylonQuickFixAssistant.java:142)
    at org.eclipse.imp.editor.internal.QuickFixController.collectCorrections(QuickFixController.java:233)
    at org.eclipse.imp.editor.internal.QuickFixController.collectProposals(QuickFixController.java:139)
    at org.eclipse.imp.editor.internal.QuickFixController.computeQuickAssistProposals(QuickFixController.java:178)
    at org.eclipse.jface.text.quickassist.QuickAssistAssistant$ContentAssistProcessor.computeCompletionProposals(QuickAssistAssistant.java:75)
    at org.eclipse.jface.text.contentassist.ContentAssistant.computeCompletionProposals(ContentAssistant.java:1830)
    at org.eclipse.jface.text.contentassist.CompletionProposalPopup.computeProposals(CompletionProposalPopup.java:556)
    at org.eclipse.jface.text.contentassist.CompletionProposalPopup.access$16(CompletionProposalPopup.java:553)
    at org.eclipse.jface.text.contentassist.CompletionProposalPopup$2.run(CompletionProposalPopup.java:488)
    at org.eclipse.swt.custom.BusyIndicator.showWhile(BusyIndicator.java:70)
    at org.eclipse.jface.text.contentassist.CompletionProposalPopup.showProposals(CompletionProposalPopup.java:482)
    at org.eclipse.jface.text.contentassist.ContentAssistant.showPossibleCompletions(ContentAssistant.java:1656)
    at org.eclipse.jface.text.quickassist.QuickAssistAssistant.showPossibleQuickAssists(QuickAssistAssistant.java:128)
    at org.eclipse.jface.text.source.SourceViewer.doOperation(SourceViewer.java:933)
    at org.eclipse.jface.text.source.projection.ProjectionViewer.doOperation(ProjectionViewer.java:1534)
    at org.eclipse.imp.editor.StructuredSourceViewer.doOperation(StructuredSourceViewer.java:129)
    at org.eclipse.ui.texteditor.TextOperationAction$1.run(TextOperationAction.java:128)
    at org.eclipse.swt.custom.BusyIndicator.showWhile(BusyIndicator.java:70)
    at org.eclipse.ui.texteditor.TextOperationAction.run(TextOperationAction.java:126)
    at org.eclipse.jface.action.Action.runWithEvent(Action.java:498)
    at org.eclipse.ui.commands.ActionHandler.execute(ActionHandler.java:185)
    at org.eclipse.ui.internal.handlers.LegacyHandlerWrapper.execute(LegacyHandlerWrapper.java:109)
    at org.eclipse.core.commands.Command.executeWithChecks(Command.java:476)
    at org.eclipse.core.commands.ParameterizedCommand.executeWithChecks(ParameterizedCommand.java:508)
    at org.eclipse.ui.internal.handlers.HandlerService.executeCommand(HandlerService.java:169)
    at org.eclipse.ui.internal.keys.WorkbenchKeyboard.executeCommand(WorkbenchKeyboard.java:468)
    at org.eclipse.ui.internal.keys.WorkbenchKeyboard.press(WorkbenchKeyboard.java:786)
    at org.eclipse.ui.internal.keys.WorkbenchKeyboard.processKeyEvent(WorkbenchKeyboard.java:885)
    at org.eclipse.ui.internal.keys.WorkbenchKeyboard.filterKeySequenceBindings(WorkbenchKeyboard.java:567)
    at org.eclipse.ui.internal.keys.WorkbenchKeyboard.access$3(WorkbenchKeyboard.java:508)
    at org.eclipse.ui.internal.keys.WorkbenchKeyboard$KeyDownFilter.handleEvent(WorkbenchKeyboard.java:123)
    at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java:84)
    at org.eclipse.swt.widgets.Display.filterEvent(Display.java:1531)
    at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1257)
    at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1282)
    at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1267)
    at org.eclipse.swt.widgets.Widget.sendKeyEvent(Widget.java:1294)
    at org.eclipse.swt.widgets.Widget.gtk_key_press_event(Widget.java:730)
    at org.eclipse.swt.widgets.Control.gtk_key_press_event(Control.java:3019)
    at org.eclipse.swt.widgets.Composite.gtk_key_press_event(Composite.java:734)
    at org.eclipse.swt.widgets.Widget.windowProc(Widget.java:1743)
    at org.eclipse.swt.widgets.Control.windowProc(Control.java:5016)
    at org.eclipse.swt.widgets.Display.windowProc(Display.java:4408)
    at org.eclipse.swt.internal.gtk.OS._gtk_main_do_event(Native Method)
    at org.eclipse.swt.internal.gtk.OS.gtk_main_do_event(OS.java:8394)
    at org.eclipse.swt.widgets.Display.eventProc(Display.java:1245)
    at org.eclipse.swt.internal.gtk.OS._g_main_context_iteration(Native Method)
    at org.eclipse.swt.internal.gtk.OS.g_main_context_iteration(OS.java:2258)
    at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3207)
    at org.eclipse.ui.internal.Workbench.runEventLoop(Workbench.java:2696)
    at org.eclipse.ui.internal.Workbench.runUI(Workbench.java:2660)
    at org.eclipse.ui.internal.Workbench.access$4(Workbench.java:2494)
    at org.eclipse.ui.internal.Workbench$7.run(Workbench.java:674)
    at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:332)
    at org.eclipse.ui.internal.Workbench.createAndRunWorkbench(Workbench.java:667)
    at org.eclipse.ui.PlatformUI.createAndRunWorkbench(PlatformUI.java:149)
    at org.eclipse.ui.internal.ide.application.IDEApplication.start(IDEApplication.java:123)
    at org.eclipse.equinox.internal.app.EclipseAppHandle.run(EclipseAppHandle.java:196)
    at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.runApplication(EclipseAppLauncher.java:110)
    at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.start(EclipseAppLauncher.java:79)
    at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:344)
    at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:179)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:597)
    at org.eclipse.equinox.launcher.Main.invokeFramework(Main.java:622)
    at org.eclipse.equinox.launcher.Main.basicRun(Main.java:577)
    at org.eclipse.equinox.launcher.Main.run(Main.java:1410)
    at org.eclipse.equinox.launcher.Main.main(Main.java:1386)

[davidfestal]

Is it possible to detail a bit the context when this exception appeared ? What was the file : ceyon file from a ceylon project, for a non-ceylon project, Ceylon file in a declared source directory or elsewhere in the project ?
I've identified where this error comes from in the code, but for the moment I can't reproduce it.

[FroMage]

I really don't remember.