Strange casting error when using lamdas

[Robert M. Münch]

On 2019-12-03 16:34:43 +0000, Robert M. Münch said:

> I have very strange casting error I don't understand:
> 
> alias typeof(windows_message_streams[WM_MOUSEMOVE].filter!(win => 
> (win.wParam & MK_LBUTTON))) WM_MOUSEMOVE_LBUTTON_TYPE;
> WM_MOUSEMOVE_LBUTTON_TYPE WM_MOUSEMOVE_LBUTTON_STREAM;
> pragma(msg,typeof(WM_MOUSEMOVE_LBUTTON_STREAM));
> 
>>> FilterObservable!(__lambda39, SubjectObject!(OS_State))
> 
> WM_MOUSEMOVE_LBUTTON_STREAM = 
> cast(WM_MOUSEMOVE_LBUTTON_TYPE)(windows_message_streams[WM_MOUSEMOVE].filter!(win 
> => (win.wParam & MK_LBUTTON)));
> pragma(msg,typeof(wstreams[WM_MOUSEMOVE].filter!(win => (win.wParam & 
> MK_LBUTTON))));
> 
>>> FilterObservable!(__lambda7, SubjectObject!(OS_State))
> 
> ..\..\gui.d(317,104): Error: cannot cast expression 
> filter(windows_message_streams[512u]) of type 
> FilterObservable!(__lambda6, SubjectObject!(OS_State)) to 
> FilterObservable!(__lambda39, SubjectObject!(OS_State)) because of 
> different sizes
> FilterObservable!(__lambda7, SubjectObject!(OS_State))
> 
> My code worked in the past but now it doesn't and I don't know why. I 
> don't understand the "because of different sizes" message.
> 
> It looks like I have to explicitly create a lambda and re-use it. But 
> how to do that?

So, it all boils down to a breaking change in the RX framework... which 
I still don't understand...

-- 
Robert M. Münch
http://www.saphirion.com
smarter | better | faster