bug#20660: 25.0.50; Window pops now issue "Args out of range" with popwin mode enabled

[Eli Zaretskii]

> From: Kaushal <kaushal.modi@gmail.com>
> Date: Thu, 11 Jun 2015 15:10:44 +0000
> 
> Any hints on how I can debug this more?

I'm not Dmitry, but I will give advice nonetheless.

Try running Emacs under GDB, setting a breakpoint in the function
named args_out_of_range.  When it breaks, the command "xbacktrace"
(defined in src/.gdbinit) will display a Lisp-level backtrace, whuch
might give you enough hints to find the culprit.  If not, the command
"backtrace" will show a C-level backtrace; post it here if you cannot
figure it out.

If the breakpoint in args_out_of_range breaks too much in situations
not related to your problem, you can make the breakpoint continue the
execution automatically:

  (gdb) break args_out_of_range
  (gdb) commands
    > xbacktrace
    > continue
    >end

Then only look at the output of GDB when you see the problem
happening.