bug#38731: 27.0.50; Unexpected redisplay behaviour. Cursor can’t be moved to end of line.

[Eli Zaretskii]

> Date: Tue, 24 Dec 2019 18:43:34 +0800
> From: HaiJun Zhang <netjune@outlook.com>
> 
> 1. emacs -Q
> 2. open the test file in attachment(a.cpp)
> 3. M-x toggle-truncate-lines
> 4. M-x global-hl-line
> 5. shrink the width of the emacs window so that the longest line(#12) can’t 
> be fully visible
> 6. go to line 12 and press C-e to goto end of line
> 7. the cursor is not at the end of line and you can’t move the cursor to end 
> of line

I cannot reproduce this.

Note how in the video you produced, moving cursor across the
right-most part of the line after C-e shows characters from the end of
the line.  IOW, Emacs does know it is at EOL, it's just that the
window display somehow was not updated.

I think this is Darwin-specific display problem.