bug#33688: UTF symbols in 25.2.2 under Ubuntu

[Sergei Meshveliani <mechvel@botik.ru>]

From: mechvel <mechvel@botik.ru>
To: bug-gnu-emacs@gnu.org
Subject: 25.2; UTF symbols

Dear Emacs team,

This is on  GNU Emacs 25.2.2  installed on Ubuntu Linux 18.04 LTS.
It draws wrongly some UTF symbols.

I see this when writing programs in Agda.
Agda is a programming language that uses some UTF symbols in the source
code. It has a certain Agda input method for UTF symbols.
For example, in
                    A\rB          (1)

\r is an UTF symbol \rightarrow in Agda programs.
(1) needs to be drawn somewht similar to
                                         A->B

But emacs draws the part `>' of the arrow inside B, so that the string
looks like
                    A-B

, and with with a certain garbage inside B. 

Another example: there is a particular arrow which is input by the
Agda input method as
                       \-->

It is intended to be as  \r  but a small bit different.
Emacs under Debian Linux draws it so that I cannot distinguish it from
drawing \r.  So that it draws
                               _Preserves_\r-->_
as close to                    _Preserves_->_
, which is mainly all right.

But  GNU Emacs 25.2.2 under Ubuntu 18.04  draws it as

                           _Preserves_-->
                                        _

, where the arrow is long, and its `>' part reaches even further than
the last underscore.


Comment about how UTF gets to Agda programs via emacs
=====================================================

To install the Agda input method one needs to put into  .emacs
a Lisp code somewhat of this kind

--------------------------------------------------------------------
(load-file (let ((coding-system-for-read 'utf-8))
                   (shell-command-to-string "agda-mode locate")))

(custom-set-variables
 ;; custom-set-variables was added by Custom.
 ;; If you edit it by hand, you could mess it up, so be careful.
 ;; Your init file should contain only one such instance.
 ;; If there is more than one, they won't work right.
 '(agda2-abort-highlighting (quote interactive))
 '(agda2-program-args
   (quote
    ("-i" "." "-i" "/home/mechvel/agda/stLib/dec4-2018/src" "-i"
"/home/mechvel\
/agda/UNPrelude/src" "-i" "/home/mechvel/poly/0.1" "+RTS" "-K200m"
"-M15G" "-RT\
S"))))
(custom-set-faces
 ;; custom-set-faces was added by Custom.
 ;; If you edit it by hand, you could mess it up, so be careful.
 ;; Your init file should contain only one such instance.
 ;; If there is more than one, they won't work right.
 )
-------------------------------------------------------------------


Some part of it get there by the  emacs  commands

  load-library agda2-mode
  customize-group agda2
  ...

  > agda-mode compile


Regards,

------
Sergei



======================================================================
This text has been generated automatically by emacs.
Probably it describes the precise configuration:
 

In GNU Emacs 25.2.2 (x86_64-pc-linux-gnu, GTK+ Version 3.22.21)
 of 2017-09-22, modified by Debian built on lgw01-amd64-050
System Description:     Ubuntu 18.04.1 LTS

Configured using:
 'configure --build x86_64-linux-gnu --prefix=/usr
 --sharedstatedir=/var/lib --libexecdir=/usr/lib
 --localstatedir=/var/lib --infodir=/usr/share/info
 --mandir=/usr/share/man --with-pop=yes

--enable-locallisppath=/etc/emacs25:/etc/emacs:/usr/local/share/emacs/25.2/sit\
e-lisp:/usr/local/share/emacs/site-lisp:/usr/share/emacs/25.2/site-lisp:/usr/sh\
are/emacs/site-lisp
 --with-sound=alsa --without-gconf --build x86_64-linux-gnu
 --prefix=/usr --sharedstatedir=/var/lib --libexecdir=/usr/lib
 --localstatedir=/var/lib --infodir=/usr/share/info
 --mandir=/usr/share/man --with-pop=yes

--enable-locallisppath=/etc/emacs25:/etc/emacs:/usr/local/share/emacs/25.2/sit\
e-lisp:/usr/local/share/emacs/site-lisp:/usr/share/emacs/25.2/site-lisp:/usr/sh\
are/emacs/site-lisp
 --with-sound=alsa --without-gconf --with-x=yes --with-x-toolkit=gtk3
 --with-toolkit-scroll-bars 'CFLAGS=-g -O2
 -fdebug-prefix-map=/build/emacs25-jYekUr/emacs25-25.2+1=.
-fstack-protector-st\
rong -Wformat -Werror=format-security -Wall' 'CPPFLAGS=-Wdate-time
 -D_FORTIFY_SOURCE=2' 'LDFLAGS=-Wl,-Bsymbolic-functions -Wl,-z,relro''

Configured features:
XPM JPEG TIFF GIF PNG RSVG IMAGEMAGICK SOUND GPM DBUS GSETTINGS NOTIFY
ACL LIBSELINUX GNUTLS LIBXML2 FREETYPE M17N_FLT LIBOTF XFT ZLIB
TOOLKIT_SCROLL_BARS GTK3 X11

Important settings:
  value of $LANG: ru_RU.UTF-8
  value of $XMODIFIERS: @im=ibus
  locale-coding-system: utf-8-unix

Major mode: Fundamental

Minor modes in effect:
  tooltip-mode: t
  global-eldoc-mode: t
  electric-indent-mode: t
  mouse-wheel-mode: t
  tool-bar-mode: t
  menu-bar-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t
  buffer-read-only: t
  line-number-mode: t
  transient-mark-mode: t

Recent messages:
Loading 00debian-vars...done
Loading /etc/emacs/site-start.d/50dictionaries-common.el (source)...
Loading debian-ispell...
Loading /var/cache/dictionaries-common/emacsen-ispell-default.el
(source)...don\
e
Loading debian-ispell...done
Loading /var/cache/dictionaries-common/emacsen-ispell-dicts.el
(source)...done
Loading /etc/emacs/site-start.d/50dictionaries-common.el (source)...done
Loading /etc/emacs/site-start.d/50tcsh.el (source)...done
Loading /home/mechvel/.cabal/share/x86_64-linux-ghc-8.0.2/Agda-2.6.0/emacs-mode\
/agda2.el (source)...done
For information about GNU Emacs and the GNU system, type C-h C-a.

Load-path shadows:
/usr/share/emacs/25.2/site-lisp/debian-startup
hides /usr/share/emacs/site-lisp\
/debian-startup

Features:
(shadow sort mail-extr emacsbug message dired format-spec rfc822 mml
mml-sec password-cache epg epg-config gnus-util mm-decode mm-bodies
mm-encode mail-parse rfc2231 mailabbrev gmm-utils mailheader sendmail
rfc2047 rfc2045 ietf-drums mm-util help-fns help-mode easymenu
cl-loaddefs pcase cl-lib mail-prsvr mail-utils term/xterm xterm
time-date agda2 mule-util cyril-util tooltip eldoc electric uniquify
ediff-hook vc-hooks lisp-float-type mwheel x-win term/common-win x-dnd
tool-bar dnd fontset image regexp-opt fringe tabulated-list newcomment
elisp-mode lisp-mode prog-mode register page menu-bar rfn-eshadow timer
select scroll-bar mouse jit-lock font-lock syntax facemenu font-core
frame cl-generic cham georgian utf-8-lang misc-lang vietnamese tibetan
thai tai-viet lao korean japanese eucjp-ms cp51932 hebrew greek romanian
slovak czech european ethiopic indian cyrillic chinese charscript
case-table epa-hook jka-cmpr-hook help simple abbrev minibuffer
cl-preloaded nadvice loaddefs button faces cus-face macroexp files
text-properties overlay sha1 md5 base64 format env code-pages mule
custom widget hashtable-print-readable backquote dbusbind inotify
dynamic-setting system-font-setting font-render-setting move-toolbar gtk
x-toolkit x multi-tty make-network-process emacs)

Memory information:
((conses 16 91504 4904)
 (symbols 48 19952 0)
 (miscs 40 79 97)
 (strings 32 14896 4789)
 (string-bytes 1 422389)
 (vectors 16 9971)
 (vector-slots 8 389091 16959)
 (floats 8 166 371)
 (intervals 56 255 13)
 (buffers 976 19))