bug#35316: 26.2; Emacs lags in c++-mode buffer when editing with iedit-mode on

[Amos Bird]

Hi Alan!

> Are we still talking about C++ Mode

Yeah it's c++ mode but it can also be reproduced with c mode.
The minute long frozen is caused mainly by the lsp-mode, howeveer
it's still laggy after turning lsp off.

> How big is your file?  Can you characterise it in any way?

You can try emacs/src/xdisp.c . iediting all "make_fixnum",
turning them into "make_fixnum_why_undo_redo_is_so_slow", and 
undo.
It's about 10-20 seconds freezing time here.

> It seems I have more work to do on this in any case.

Looking forward to it!

regards,

--
Amos Bird
amosbird@gmail.com