"Add existing item" into a project virtual sub-folder causes ReSharper exception

Every time I try to send ReSharper exceptions to ITN, I get HTTP 400 errors,
so I thought I should post it here instead...

While importing two read-only XML files into a subfolder of a C++ project
that is part of an overall C#/C++ solution, where the subfolder in the
project is a virtual subfolder that has no matching physical subfolder on
the hard drive (i.e. the xml files are stored in the project's root
directory), I received the following exception:

JetBrains.ReSharper.Util.InternalErrorException: An exception has
occurred ---> JetBrains.ReSharper.Util.InternalErrorException: An internal
error has occurred

at JetBrains.ReSharper.Util.InternalErrorException..ctor(String, Exception)
in c:\TEMP\tmpDE05.tmp\src\Util\src\InternalErrorException.cs:line 28 column
7
at JetBrains.ReSharper.Util.Logger.Assert(Boolean, String, Object[]) in
c:\TEMP\tmpDE05.tmp\src\Util\src\Logger.cs:line 104 column 11
at JetBrains.ReSharper.Util.FileSystemPath.GetCanonicalPath(String) in
c:\TEMP\tmpDE05.tmp\src\Util\src\FileSystemPath.cs:line 298 column 6
at JetBrains.ReSharper.Util.FileSystemPath..ctor(String) in
c:\TEMP\tmpDE05.tmp\src\Util\src\FileSystemPath.cs:line 28 column 7
at
JetBrains.ReSharper.ProjectModel.VSIntegration.ProjectModelSynchronizer.CreateMissingAncestors(IVsHierarchy,
UInt32) in
c:\TEMP\tmpDE05.tmp\src\VSIntegration\src\ProjectModel\ProjectModelSynchronizer.cs:line
426 column 8
at
JetBrains.ReSharper.ProjectModel.VSIntegration.ProjectModelSynchronizer.HandleAdd(Int32,
IVsProject[], Int32[], String[], Boolean) in
c:\TEMP\tmpDE05.tmp\src\VSIntegration\src\ProjectModel\ProjectModelSynchronizer.cs:line
266 column 11
at
JetBrains.ReSharper.ProjectModel.VSIntegration.MyPendingAddFilesEvent.TryHandle()
in
c:\TEMP\tmpDE05.tmp\src\VSIntegration\src\ProjectModel\VSSolutionManager.cs:line
466 column 9
at
JetBrains.ReSharper.VSIntegration.PendingEventLog.AddPendingEvent(PendingEvent)
in c:\TEMP\tmpDE05.tmp\src\VSIntegration\src\Util\PendingEventLog.cs:line 27
column 7
at
JetBrains.ReSharper.ProjectModel.VSIntegration.c__DisplayClasse.b__d() in c:\TEMP\tmpDE05.tmp\src\VSIntegration\src\ProjectModel\VSSolutionManager.cs:line 479 column 35 at JetBrains.ReSharper.Shell.PendingAction.Execute() in c:\TEMP\tmpDE05.tmp\src\Shell\src\Invocator.cs:line 219 column 11 at JetBrains.ReSharper.Shell.Invocator.ProcessQueue() in c:\TEMP\tmpDE05.tmp\src\Shell\src\Invocator.cs:line 163 column 11 at System.RuntimeMethodHandle._InvokeMethodFast(Object, Object[], SignatureStruct&, MethodAttributes, RuntimeTypeHandle) at System.RuntimeMethodHandle.InvokeMethodFast(Object, Object[], Signature, MethodAttributes, RuntimeTypeHandle) at System.Reflection.RuntimeMethodInfo.Invoke(Object, BindingFlags, Binder, Object[], CultureInfo, Boolean) at System.Delegate.DynamicInvokeImpl(Object[]) at System.Windows.Forms.Control.InvokeMarshaledCallbackDo(ThreadMethodEntry) at System.Windows.Forms.Control.InvokeMarshaledCallbackHelper(Object) at System.Threading.ExecutionContext.runTryCode(Object) at System.Runtime.CompilerServices.RuntimeHelpers.ExecuteCodeWithGuaranteedCleanup(TryCode, CleanupCode, Object) at System.Threading.ExecutionContext.RunInternal(ExecutionContext, ContextCallback, Object) at System.Threading.ExecutionContext.Run(ExecutionContext, ContextCallback, Object) at System.Windows.Forms.Control.InvokeMarshaledCallback(ThreadMethodEntry) at System.Windows.Forms.Control.InvokeMarshaledCallbacks() at System.Windows.Forms.Control.WndProc(Message&) at System.Windows.Forms.ScrollableControl.WndProc(Message&) at System.Windows.Forms.ContainerControl.WndProc(Message&) at System.Windows.Forms.Form.WndProc(Message&) at System.Windows.Forms.ControlNativeWindow.OnMessage(Message&) at System.Windows.Forms.ControlNativeWindow.WndProc(Message&) at System.Windows.Forms.NativeWindow.DebuggableCallback(IntPtr, Int32, IntPtr, IntPtr) at JetBrains.ReSharper.Util.Logger.Assert(Boolean condition, String messageFormat, Object[] args) in c:\TEMP\tmpDE05.tmp\src\Util\src\Logger.cs:line 104 --- End of inner exception stack trace --- at JetBrains.ReSharper.Util.Logger.LogExceptionEx(Exception, String, Boolean) in c:\TEMP\tmpDE05.tmp\src\Util\src\Logger.cs:line 297 column 9 at JetBrains.ReSharper.Util.Logger.LogException(Exception) in c:\TEMP\tmpDE05.tmp\src\Util\src\Logger.cs:line 309 column 5 at JetBrains.ReSharper.Util.Logger.Assert(Boolean, String, Object[]) in c:\TEMP\tmpDE05.tmp\src\Util\src\Logger.cs:line 108 column 11 at JetBrains.ReSharper.Util.FileSystemPath.GetCanonicalPath(String) in c:\TEMP\tmpDE05.tmp\src\Util\src\FileSystemPath.cs:line 298 column 6 at JetBrains.ReSharper.Util.FileSystemPath..ctor(String) in c:\TEMP\tmpDE05.tmp\src\Util\src\FileSystemPath.cs:line 28 column 7 at JetBrains.ReSharper.ProjectModel.VSIntegration.ProjectModelSynchronizer.CreateMissingAncestors(IVsHierarchy, UInt32) in c:\TEMP\tmpDE05.tmp\src\VSIntegration\src\ProjectModel\ProjectModelSynchronizer.cs:line 426 column 8 at JetBrains.ReSharper.ProjectModel.VSIntegration.ProjectModelSynchronizer.HandleAdd(Int32, IVsProject[], Int32[], String[], Boolean) in c:\TEMP\tmpDE05.tmp\src\VSIntegration\src\ProjectModel\ProjectModelSynchronizer.cs:line 266 column 11 at JetBrains.ReSharper.ProjectModel.VSIntegration.MyPendingAddFilesEvent.TryHandle() in c:\TEMP\tmpDE05.tmp\src\VSIntegration\src\ProjectModel\VSSolutionManager.cs:line 466 column 9 at JetBrains.ReSharper.VSIntegration.PendingEventLog.AddPendingEvent(PendingEvent) in c:\TEMP\tmpDE05.tmp\src\VSIntegration\src\Util\PendingEventLog.cs:line 27 column 7 at JetBrains.ReSharper.ProjectModel.VSIntegration.<>c__DisplayClasse.]]>b__d()
in
c:\TEMP\tmpDE05.tmp\src\VSIntegration\src\ProjectModel\VSSolutionManager.cs:line
479 column 35
at JetBrains.ReSharper.Shell.PendingAction.Execute() in
c:\TEMP\tmpDE05.tmp\src\Shell\src\Invocator.cs:line 219 column 11
at JetBrains.ReSharper.Shell.Invocator.ProcessQueue() in
c:\TEMP\tmpDE05.tmp\src\Shell\src\Invocator.cs:line 163 column 11
at System.RuntimeMethodHandle._InvokeMethodFast(Object, Object[],
SignatureStruct&, MethodAttributes, RuntimeTypeHandle)
at System.RuntimeMethodHandle.InvokeMethodFast(Object, Object[], Signature,
MethodAttributes, RuntimeTypeHandle)
at System.Reflection.RuntimeMethodInfo.Invoke(Object, BindingFlags, Binder,
Object[], CultureInfo, Boolean)
at System.Delegate.DynamicInvokeImpl(Object[])
at
System.Windows.Forms.Control.InvokeMarshaledCallbackDo(ThreadMethodEntry)
at System.Windows.Forms.Control.InvokeMarshaledCallbackHelper(Object)
at System.Threading.ExecutionContext.runTryCode(Object)
at
System.Runtime.CompilerServices.RuntimeHelpers.ExecuteCodeWithGuaranteedCleanup(TryCode,
CleanupCode, Object)
at System.Threading.ExecutionContext.RunInternal(ExecutionContext,
ContextCallback, Object)
at System.Threading.ExecutionContext.Run(ExecutionContext, ContextCallback,
Object)
at System.Windows.Forms.Control.InvokeMarshaledCallback(ThreadMethodEntry)
at System.Windows.Forms.Control.InvokeMarshaledCallbacks()
at System.Windows.Forms.Control.WndProc(Message&)
at System.Windows.Forms.ScrollableControl.WndProc(Message&)
at System.Windows.Forms.ContainerControl.WndProc(Message&)
at System.Windows.Forms.Form.WndProc(Message&)
at System.Windows.Forms.ControlNativeWindow.OnMessage(Message&)
at System.Windows.Forms.ControlNativeWindow.WndProc(Message&)
at System.Windows.Forms.NativeWindow.DebuggableCallback(IntPtr, Int32,
IntPtr, IntPtr)