This seems to be a problem cause by outdated,
haskell-cmark-gfm / cmark-gfm dependencies.
Found this issue already reported in January 2019,
viewtopic.php?f=15&t=13358&p=60320
but the thread is locked because the post expired
$ uname -a
$this->bbcode_second_pass_code('', 'Linux alarm 5.5.6-1-ARCH #1 SMP PREEMPT Wed Feb 26 00:56:53 UTC 2020 armv7l GNU/Linux')
$ pacman -Qs pandoc
$this->bbcode_second_pass_code('', 'local/haskell-doctemplates 0.2.2.1-47
Pandoc-style document templates
local/haskell-pandoc-types 1.17.5.4-2
Types for representing a structured document
local/pandoc 2.3.1-24
Conversion between markup formats')
Notice, local/pandoc 2.3.1-24 but, https://pandoc.org/releases.html pandoc 2.9.2 (2020-02-15)
$ pacman -Si pandoc
$this->bbcode_second_pass_code('', 'Version : 2.3.1-24
Depends On : ghc-libs haskell-http haskell-juicypixels haskell-sha haskell-aeson haskell-aeson-pretty
haskell-base-compat haskell-base64-bytestring haskell-blaze-html haskell-blaze-markup
haskell-case-insensitive haskell-cmark-gfm haskell-data-default haskell-doctemplates
haskell-exceptions haskell-glob haskell-haddock-library haskell-skylighting haskell-hslua
haskell-hslua-module-text haskell-http-client haskell-syb haskell-hsyaml
haskell-http-client-tls haskell-http-types haskell-safe haskell-split haskell-texmath
haskell-network haskell-pandoc-types haskell-random haskell-tagsoup haskell-temporary
haskell-network-uri haskell-unordered-containers haskell-zip-archive haskell-vector
haskell-xml haskell-zlib
Optional Deps : pandoc-citeproc: for citation rendering with pandoc-citeproc filter
pandoc-crossref: for numbering figures, equations, tables and cross-references to them with
pandoc-crossref filter
texlive-core: for pdf output
Conflicts With : haskell-pandoc
Replaces : haskell-pandoc
')
Notice this dependency, haskell-cmark-gfm and this ???
$this->bbcode_second_pass_quote('', 'C')onflicts With : haskell-pandoc
Replaces : haskell-pandoc