bug#28293: 24.5; Haskell Mode Hangs on loading large complex file

[Andreas Röhler]

May confirm the bug from GNU Emacs 25.1.91.1 (i686-pc-linux-gnu, GTK+ Version 3.14.5) of 2017-01-02
With emacs -Q it opens quickly, but hangs when moving down.
Without -Q emacs freezes.

Assume the length of line is the reason, not the file resp. the mode.

BTW haskell-mode is developed at https://github.com/haskell

On 30.08.2017 16:38, Eli Zaretskii wrote:

From: Mike Dupont <jamesmikedupont@googlemail.com>
Date: Wed, 30 Aug 2017 06:03:56 -0400

Load this large haskell file
it hangs emacs, I think it is something in the mode.

https://github.com/h4ck3rm1k3/gcc-ontology/blob/7889b822218950fcdc414a4e054d6e7bb4a3e52e/tests/test_haskell1_b.hs

It doesn't hang here, neither with Emacs 24.5 nor with the current
master.  It displays the first screenful rather quickly, and then
works very sluggishly, even at the beginning of the buffer, much worse
at the end.  But the latter is a known issue: this file is a single
11MB line of text, and Emacs's display is very slow with such long
lines.