Bug#846279: ghc: Problems with Backspace, Delete and arrow keys

[Richard Smith]

Package: ghc
Version: 8.0.1-14
Severity: normal

Dear Maintainer,

Since upgrading to ghc 8.0.1, when trying to backspace user-entered text (e.g. a getLine event) in a
running haskell program (whether compiled with this version of ghc, or interpreted), the terminal
displays "^?" for backspace, "^[[3~" for delete and other codes for arrow keys.

It appears to be previously reported, and resolved, here: https://ghc.haskell.org/trac/ghc/ticket/2606

Looks to be a problem with how ghci is compiled and libedit/libreadline/ncurses-dev as the module 
"System.Console.Editline.Readline" is missing:

GHCi, version 8.0.1: http://www.haskell.org/ghc/  :? for help
Prelude> :browse System.Console.Editline.Readline

<no location info>: error:
    Could not find module ‘System.Console.Editline.Readline’
    It is not a module in the current program, or in any known package.


Many thanks!

-- System Information:
Debian Release: stretch/sid
  APT prefers testing
  APT policy: (500, 'testing')
Architecture: amd64 (x86_64)

Kernel: Linux 4.8.0-1-amd64 (SMP w/8 CPU cores)
Locale: LANG=en_GB.UTF-8, LC_CTYPE=en_GB.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)

Versions of packages ghc depends on:
ii  dpkg             1.18.15
ii  gcc              4:6.1.1-1
ii  libbsd-dev       0.8.3-1
ii  libc6            2.24-5
ii  libc6-dev        2.24-5
ii  libffi-dev       3.2.1-6
ii  libffi6          3.2.1-6
ii  libgmp-dev       2:6.1.1+dfsg-1
ii  libgmp10         2:6.1.1+dfsg-1
ii  libncurses5-dev  6.0+20160917-1
ii  libtinfo5        6.0+20160917-1

ghc recommends no packages.

Versions of packages ghc suggests:
pn  ghc-doc      <none>
pn  ghc-prof     <none>
pn  haskell-doc  <none>
pn  llvm-3.7     <none>
ii  perl         5.24.1~rc3-3

-- no debconf information