System.Reflection.TargetException gtk-clock under .Net

[diakopter]

under cmd.exe (and cygwin also, separately; both produce the same error) under .Net:
C:\Users\mwilson\src\niecza>run\Niecza.exe examples\gtk-clock.pl
Unhandled exception: System.Reflection.TargetException: Non-static method requir
es a target.
at System.Reflection.RuntimeConstructorInfo.CheckConsistency(Object target)
at System.Reflection.RuntimeConstructorInfo.Invoke(Object obj, BindingFlags i
nvokeAttr, Binder binder, Object[] parameters, CultureInfo culture)
at Niecza.OverloadCandidate.Invoke(Object obj, Variable[] pos, VarHash named)

at Niecza.CLRWrapperProvider.c__AnonStoreyA.<>m__B(Frame th)
at Niecza.Kernel.RunCore(Frame& cur)
at line 0 (CLR::Gtk::Window.new @ 0)
at C:\Users\mwilson\src\niecza\examples\gtk-clock.pl line 17 (MAIN mainline @
2)
at C:\Users\mwilson\src\niecza\lib\CORE.setting line 2115 (CORE C1022_ANON @ 2
)
at C:\Users\mwilson\src\niecza\lib\CORE.setting line 2116 (CORE module-CORE @
58)
at C:\Users\mwilson\src\niecza\lib\CORE.setting line 2116 (CORE mainline @ 1)

at line 0 (boot-MAIN @ 1)
at line 0 (ExitRunloop @ 0)
at C:\Users\mwilson\src\niecza\boot\lib\CORE.setting line 685 (CORE die @ 2)
at C:\Users\mwilson\src\niecza\src\NieczaBackendDotnet.pm6 line 37 (NieczaBack
endDotnet NieczaBackendDotnet.accept @ 13)
at C:\Users\mwilson\src\niecza\src\NieczaCompiler.pm6 line 32 (NieczaCompiler
C19_ANON @ 4)
at C:\Users\mwilson\src\niecza\src\NieczaCompiler.pm6 line 38 (NieczaCompiler
NieczaCompiler.compile @ 18)
at C:\Users\mwilson\src\niecza\src\NieczaCompiler.pm6 line 68 (NieczaCompiler
NieczaCompiler.compile_file @ 5)
at C:\Users\mwilson\src\niecza\src\niecza line 306 (MAIN mainline @ 107)
at C:\Users\mwilson\src\niecza\boot\lib\CORE.setting line 1933 (CORE C906_ANON
@ 2)
at C:\Users\mwilson\src\niecza\boot\lib\CORE.setting line 1934 (CORE module-CO
RE @ 56)
at C:\Users\mwilson\src\niecza\boot\lib\CORE.setting line 1934 (CORE mainline
@ 1)
at line 0 (boot-MAIN @ 1)
at line 0 (ExitRunloop @ 0)

[samlh]

gtk-clock.pl and gtk-sierpinski.pl work for me if $cc.Target.Dispose; is commented out (line 50, line 47 resp.). gtk-tetris.pl works as is. Otherwise I get an error about being unable to find Dispose in CLR::Cairo::Surface. Full backtace below:

Exception in Gtk# callback delegate
Note: Applications can use GLib.ExceptionManager.UnhandledException to handle the exception.
System.Reflection.TargetInvocationException: Exception has been thrown by the target of an invocation. ---> Unable to resolve method Dispose in class CLR::Cairo::Surface
at C:\Users\1880337\Documents\gtk-clock.pl line 50 (ANON @ 40)
at line 0 (ExitRunloop @ 0)
--- End of inner exception stack trace ---
at System.RuntimeMethodHandle._InvokeMethodFast(Object target, Object[] arguments, SignatureStruct& sig, MethodAttributes methodAttributes, RuntimeTypeHandle typeOwner)
at System.RuntimeMethodHandle.InvokeMethodFast(Object target, Object[] arguments, Signature sig, MethodAttributes methodAttributes, RuntimeTypeHandle typeOwner)
at System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture, Boolean skipVisibilityChecks)
at System.Delegate.DynamicInvokeImpl(Object[] args)
at GLib.Signal.ClosureInvokedCB(Object o, ClosureInvokedArgs args)
at GLib.SignalClosure.Invoke(ClosureInvokedArgs args)
at GLib.SignalClosure.MarshalCallback(IntPtr raw_closure, IntPtr return_val, UInt32 n_param_vals, IntPtr param_values, IntPtr invocation_hint, IntPtr marshal_data)
at GLib.ExceptionManager.RaiseUnhandledException(Exception e, Boolean is_terminal)
at GLib.SignalClosure.MarshalCallback(IntPtr raw_closure, IntPtr return_val, UInt32 n_param_vals, IntPtr param_values, IntPtr invocation_hint, IntPtr marshal_data)
at Gtk.Application.gtk_main()
at Gtk.Application.Run()
at System.RuntimeMethodHandle._InvokeMethodFast(Object target, Object[] arguments, SignatureStruct& sig, MethodAttributes methodAttributes, RuntimeTypeHandle typeOwner)
at System.RuntimeMethodHandle.InvokeMethodFast(Object target, Object[] arguments, Signature sig, MethodAttributes methodAttributes, RuntimeTypeHandle typeOwner)
at System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture, Boolean skipVisibilityChecks)
at System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture)
at Niecza.OverloadCandidate.Invoke(Frame th, Variable[] pos, VarHash named)
at Niecza.CandidateSet.DoDispatch(Frame th, Variable[] pos, VarHash named, P6any junc_call)
at Niecza.CLRWrapperProvider.Binder(Frame th)
at Niecza.Kernel.RunCore(Frame& cur)
at Niecza.Kernel.RunInferior(Frame f)
at Niecza.RuntimeUnit.RunMainline()
at Niecza.Kernel.RunMain(RuntimeUnit main_unit)
at Niecza.CLRBackend.DowncallReceiver.run_unit(Object[] args)
at Niecza.CLRBackend.DowncallReceiver.Call(Object[] args)
at Niecza.CLRBackend.DowncallReceiver.get_Item(Object i)
at Niecza.Downcaller.DownCall(Variable list)
at Niecza.C2542downcall(Frame )
at Niecza.Kernel.RunCore(Frame& cur)
at Niecza.Kernel.RunInferior(Frame f)
at Niecza.RuntimeUnit.RunMainline()
at Niecza.Kernel.RunMain(RuntimeUnit main_unit)
at Niecza.Kernel.MainHandler(String uname, String[] args)
at Niecza.Main(String[] )

Cairo.Context: called from finalization thread, programmer is missing a call to Dispose