私は Heist を使用するプロジェクトに取り組んでおり、最近バージョン 0.13 にアップグレードしたため、試してみたところ、元の HeistConfig が大幅に変更されていることがわかりました。
data HeistConfig m = HeistConfig
{ hcInterpretedSplices :: Splices (I.Splice m)
-- ^ Interpreted splices are the splices that Heist has always had. They
-- return a list of nodes and are processed at runtime.
, hcLoadTimeSplices :: Splices (I.Splice IO)
-- ^ Load time splices are like interpreted splices because they return a
-- list of nodes. But they are like compiled splices because they are
-- processed once at load time. All of Heist's built-in splices should be
-- used as load time splices.
, hcCompiledSplices :: Splices (C.Splice m)
-- ^ Compiled splices return a DList of Chunks and are processed at load
-- time to generate a runtime monad action that will be used to render the
-- template.
, hcAttributeSplices :: Splices (AttrSplice m)
-- ^ Attribute splices are bound to attribute names and return a list of
-- attributes.
, hcTemplateLocations :: [TemplateLocation]
-- ^ A list of all the locations that Heist should get its templates
}
defaultInterpretedSplices と defaultLoadTimeSplices があるため、[] をデフォルトの Splices として使用できなくなりました。