User command mods doesn't receive `:[count]tab` count

[kassio]

Describe the bug
:help <mods> states that :tab is one possible command modifier. On the :tab documentation is stated that it can receive a count. But, I wasn't able to receive this counter on a command.

To Reproduce

Test script

Script

function! s:fun(args)
  echo a:args
endfunction

function! s:test()
  echo '---'
  echo 'Range0: '.execute('Range0', '')
  echo 'Count0: '.execute('Count0', '')
  echo 'tab'
  echo 'tab Range0: '.execute('tab Range0', '')
  echo 'tab Count0: '.execute('tab Count0', '')
  echo '+tab'
  echo '+tab Range0: '.execute('+tab Range0', '')
  echo '+tab Count0: '.execute('+tab Count0', '')
  echo '-tab'
  echo '-tab Range0: '.execute('-tab Range0', '')
  echo '-tab Count0: '.execute('-tab Count0', '')
  echo '0tab'
  echo '0tab Range0: '.execute('0tab Range0', '')
  echo '0tab Count0: '.execute('0tab Count0', '')
  echo '$tab'
  echo '$tab Range0: '.execute('$tab Range0', '')
  echo '$tab Count0: '.execute('$tab Count0', '')
endfunction

command! Test call s:test()

command! -addr=tabs Range0 call s:fun({'qmods': <q-mods>, 'range': <range>, 'count': <count>, 'l1': <line1>, 'l2': <line2>})
command! -addr=tabs Count0 call s:fun({'qmods': <q-mods>, 'range': <range>, 'count': <count>, 'l1': <line1>, 'l2': <line2>})

Output

{'range': 0, 'qmods': '', 'count': -1, 'l2': 1, 'l1': 1}
Range0: 
{'range': 0, 'qmods': '', 'count': -1, 'l2': 1, 'l1': 1}
{'range': 0, 'qmods': '', 'count': -1, 'l2': 1, 'l1': 1}
Count0: 
{'range': 0, 'qmods': '', 'count': -1, 'l2': 1, 'l1': 1}
tab
{'range': 0, 'qmods': 'tab', 'count': -1, 'l2': 1, 'l1': 1}
tab Range0: 
{'range': 0, 'qmods': 'tab', 'count': -1, 'l2': 1, 'l1': 1}
{'range': 0, 'qmods': 'tab', 'count': -1, 'l2': 1, 'l1': 1}
tab Count0: 
{'range': 0, 'qmods': 'tab', 'count': -1, 'l2': 1, 'l1': 1}
+tab
{'range': 0, 'qmods': 'tab', 'count': -1, 'l2': 1, 'l1': 1}
+tab Range0: 
{'range': 0, 'qmods': 'tab', 'count': -1, 'l2': 1, 'l1': 1}
{'range': 0, 'qmods': 'tab', 'count': -1, 'l2': 1, 'l1': 1}
+tab Count0: 
{'range': 0, 'qmods': 'tab', 'count': -1, 'l2': 1, 'l1': 1}
-tab
{'range': 0, 'qmods': 'tab', 'count': -1, 'l2': 1, 'l1': 1}
-tab Range0: 
{'range': 0, 'qmods': 'tab', 'count': -1, 'l2': 1, 'l1': 1}
{'range': 0, 'qmods': 'tab', 'count': -1, 'l2': 1, 'l1': 1}
-tab Count0: 
{'range': 0, 'qmods': 'tab', 'count': -1, 'l2': 1, 'l1': 1}
0tab
{'range': 0, 'qmods': 'tab', 'count': -1, 'l2': 1, 'l1': 1}
0tab Range0: 
{'range': 0, 'qmods': 'tab', 'count': -1, 'l2': 1, 'l1': 1}
{'range': 0, 'qmods': 'tab', 'count': -1, 'l2': 1, 'l1': 1}
0tab Count0: 
{'range': 0, 'qmods': 'tab', 'count': -1, 'l2': 1, 'l1': 1}
$tab
{'range': 0, 'qmods': 'tab', 'count': -1, 'l2': 1, 'l1': 1}
$tab Range0: 
{'range': 0, 'qmods': 'tab', 'count': -1, 'l2': 1, 'l1': 1}
{'range': 0, 'qmods': 'tab', 'count': -1, 'l2': 1, 'l1': 1}
$tab Count0: 
{'range': 0, 'qmods': 'tab', 'count': -1, 'l2': 1, 'l1': 1}

Expected behavior
Receive the counter on <count>, or <range>.

Screenshots
If applicable, copy/paste the text or add screenshots to help explain your problem.

Environment (please complete the following information):

• iterm2: Build 3.3.12

:version

:version
VIM - Vi IMproved 8.1 (2018 May 18, compiled Jun  5 2020 21:30:37)
macOS version
Included patches: 1-503, 505-680, 682-2292
Compiled by root@apple.com
Normal version without GUI.  Features included (+) or not (-):
+acl               -browse            +cmdline_compl     +cursorbind        -emacs_tags        +float             +insert_expand     +linebreak         +modify_fname      +mouse_sgr         +netbeans_intg     +printer           +ruby/dyn          +statusline        -termguicolors     +title             +visualextra       -X11
-arabic            +builtin_terms     +cmdline_hist      +cursorshape       +eval              +folding           +job               +lispindent        +mouse             -mouse_sysmouse    +num64             -profile           +scrollbind        -sun_workshop      +terminal          -toolbar           +viminfo           -xfontset
+autocmd           +byte_offset       +cmdline_info      +dialog_con        +ex_extra          -footer            +jumplist          +listcmds          -mouseshape        -mouse_urxvt       +packages          +python/dyn        +signs             +syntax            +terminfo          +user_commands     +vreplace          -xim
+autochdir         +channel           +comments          +diff              +extra_search      +fork()            -keymap            +localmap          -mouse_dec         +mouse_xterm       +path_extra        -python3           +smartindent       +tag_binary        +termresponse      -vartabs           +wildignore        -xpm
-autoservername    +cindent           -conceal           +digraphs          -farsi             -gettext           +lambda            -lua               -mouse_gpm         +multi_byte        -perl              +quickfix          -sound             -tag_old_static    +textobjects       +vertsplit         +wildmenu          -xsmp
-balloon_eval      -clientserver      +cryptv            -dnd               +file_in_path      -hangul_input      -langmap           +menu              -mouse_jsbterm     +multi_lang        +persistent_undo   +reltime           +spell             -tag_any_white     +textprop          +virtualedit       +windows           -xterm_clipboard
-balloon_eval_term +clipboard         +cscope            -ebcdic            +find_in_path      +iconv             +libcall           +mksession         -mouse_netterm     -mzscheme          +postscript        -rightleft         +startuptime       -tcl               +timers            +visual            +writebackup       -xterm_save
   system vimrc file: "$VIM/vimrc"
     user vimrc file: "$HOME/.vimrc"
 2nd user vimrc file: "~/.vim/vimrc"
      user exrc file: "$HOME/.exrc"
       defaults file: "$VIMRUNTIME/defaults.vim"
  fall-back for $VIM: "/usr/share/vim"
Compilation: gcc -c -I. -Iproto -DHAVE_CONFIG_H   -DMACOS_X_UNIX  -g -O2 -U_FORTIFY_SOURCE -D_FORTIFY_SOURCE=1
Linking: gcc   -L/usr/local/lib -o vim        -lm -lncurses  -liconv -framework Cocoa

Additional context
Probably related to:
#760

Origin of my investigation:
kassio/neoterm#303

[brammool]

The number for the :tab modifier is not a command range, it's a separate number. Thus it can't be used for or .
We could put the actual line number before "tab", so that its the same as what was typed. Except that "$" would be turned into the line number of the last line. Would that work?

[kassio]

@brammool yes, I think that would work! Thanks!

[zeertzjq]

Fixed by patch 9.0.0786, which linked a wrong issue number.

[k-takata]

Closing, then.