Bug#899208: pandoc: FTBFS on armel/armhf: Identifier `InvalidYaml' used as a constructor-like thing

[Clint Adams]

On Sun, May 20, 2018 at 04:38:36PM -0700, John MacFarlane wrote:
> I don't understand this error.  InvalidYaml *is* a constructor for the
> type ParseException in Data.Yaml (yaml package).  So it's not clear why
> the compiler would complain about it being used as a "constructor-like
> thing."

on armel:

GHCi, version 8.2.2: http://www.haskell.org/ghc/  :? for help
Prelude> :m Data.Yaml
Prelude Data.Yaml> :i ParseException
data ParseException
  = NonScalarKey
  | UnknownAlias {_anchorName :: Text.Libyaml.AnchorName}
  | UnexpectedEvent {_received :: Maybe Text.Libyaml.Event,
                     _expected :: Maybe Text.Libyaml.Event}
  | InvalidYaml (Maybe YamlException)
  | AesonException String
  | OtherParseException GHC.Exception.SomeException
  | NonStringKeyAlias Text.Libyaml.AnchorName Value
  | CyclicIncludes
  	-- Defined in `yaml-0.8.29:Data.Yaml.Internal'
instance Show ParseException
  -- Defined in `yaml-0.8.29:Data.Yaml.Internal'

> What version of ghc is being used to compile?

8.2.2

> What version of the Haskell yaml package is being used?

0.8.29