Type variables in DataD do not match up:

When reigying an ADT, the type variables listed on the left side are different from those used on the right side:

Prelude Language.Haskell.TH> $(reify ''Maybe >>= stringE . show)
"TyConI (DataD [] Data.Maybe.Maybe [a_1627391676] [NormalC Data.Maybe.Nothing [],NormalC Data.Maybe.Just [(NotStrict,VarT a_1627391681)]] [])"

The type variables do match up when we look just at the constructor:

Prelude Language.Haskell.TH> $(reify 'Just >>= stringE . show)
"DataConI Data.Maybe.Just (ForallT [a_1627391681] [] (AppT (AppT ArrowT (VarT a_1627391681)) (AppT (ConT Data.Maybe.Maybe) (VarT a_1627391681)))) Data.Maybe.Maybe (Fixity 9 InfixL)"

Trac metadata

Trac field	Value
Version	6.7
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	Template Haskell
Test case
Differential revisions
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Operating system	Multiple
Architecture	Multiple