bug#18418: [Regression] Line number missing when enabling linum-mode

[Eli Zaretskii <eliz@gnu.org>]

> From: Ting-Yu Lin (林庭宇) <aethanyc@gmail.com>
> Date: Sun, 7 Sep 2014 00:02:51 +0800
> 
> I found a regression related to commit titled "Fix bug #17892 with
> mode/header line and display margins."
> https://github.com/emacs-mirror/emacs/commit/691d7ac6784

Sorry, I don't understand: are you saying the problem you describe
started appearing after that commit?

> 1. emacs -Q
> 2. Evaluate the following code to make the mini-buffer becomes
> multi-line.
> 
> ;;
> https://github.com/gempesaw/ido-vertical-mode.el/blob/master/ido-vertical-mode.el#L45
> (setq ido-decorations
> '("\n-> " ; left bracket around prospect list
> "" ; right bracket around prospect list
> "\n " ; separator between prospects, depends on `ido-separator`
> "\n ..." ; inserted at the end of a truncated list of prospects
> "[" ; left bracket around common match string
> "]" ; right bracket around common match string
> " [No match]"
> " [Matched]"
> " [Not readable]"
> " [Too big]"
> " [Confirm]"
> "\n-> " ; left bracket around the sole remaining completion
> "" ; right bracket around the sole remaining completion
> ))
> (ido-mode 1)
> (global-linum-mode 1)
> 
> 3. Open a large file such as src/dispextern.h in Emacs repository.
> 4. C-x C-f to find files (Notice the mini-buffer now becomes
> multi-line, and push the mode-line up. See multi_line_mini_buffer.png
> as attached.)
> 5. C-g to quit (the mini-buffer has one line again)
> 6. The line number 30 disappear, and the content of the line shifts
> left a little bit. (See line_30_missing.png) The line number at the
> area is always missing even if you scroll the file down.

Sorry, I cannot reproduce this here.  My line 30 is intact after the
above steps.