Can't capture classes inside a template haskell type quotation

GHC rejects the following:

{-# LANGUAGE TemplateHaskell #-}
import Language.Haskell.TH
class C a where
data X = X
fmap return $ instanceD (cxt []) [t| C $(conT ''X) |] []

with the error:

test.hs:5:23:
    Class `C' used as a type
    In the Template Haskell quotation [t| C $(conT 'X) |]
    In the second argument of `instanceD', namely `[t| C $(conT 'X) |]'
    In the expression: instanceD (cxt []) [t| C $(conT 'X) |] []

This is frustrating, since that quotation would have resulted in exactly the TH AST fragment I wanted, had the error not occurred. Instead I must resort to:

instanceD (cxt []) (appT (conT ''Storable) (conT ''X)) []

Incidentally, the error message produced is wrong: The error says 'X whereas I wrote ''X.

Trac metadata

Trac field	Value
Version	6.12.1
Type	FeatureRequest
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	Template Haskell
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