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Consider the following modules:

module Base where

class C a where
  inlinable :: a -> ()

{-# LANGUAGE TemplateHaskell #-}

module TH where

import Language.Haskell.TH
import Base

mkC :: Name -> Q [Dec]
mkC n = return
  [InstanceD [] (AppT (ConT ''C) (ConT n))
    [ FunD 'inlinable [Clause [WildP] (NormalB (ConE '())) []]
    ]
  ]

{-# LANGUAGE TemplateHaskell #-}

module Use where

import TH

data D = D

$(mkC ''D)

which compile just fine with GHC. Lets throw in an InlineP pragma after the FunD:

PragmaD (InlineP 'inlinable (InlineSpec True False Nothing))

Sadly, this results in an error:

Use.hs:9:3:
    `Base.inlinable' is not a (visible) method of class `Base.C'

or, with 7.2.1:

Use.hs:9:3:
    The INLINE pragma for `Base.inlinable'
      lacks an accompanying binding

OK, another try with

PragmaD (InlineP (mkName "inlinable") (InlineSpec True False Nothing))

Still a no-go in 7.3.20111130 (but accepted by 7.2.1):

Use.hs:9:3: `inlinable' is not a (visible) method of class `Base.C'

Finally, I was able to satisfy GHC by importing Base into Use. I think that names in FunD and PragmaD should be treated uniformly (i.e. using 'inlinable works/fails in both cases. I'd prefer it works, without importing Base).

Trac metadata

Trac field	Value
Version	7.3
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	Template Haskell
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