extractTyVars :: [LHsType RdrName] -> P [LHsTyVarBndr RdrName]
extractTyVars tvs = collects tvs []
where
- -- Collect all variables (1st arg serves as an accumulator)
+ -- Collect all variables (2nd arg serves as an accumulator)
+ collect :: LHsType RdrName -> [LHsTyVarBndr RdrName]
+ -> P [LHsTyVarBndr RdrName]
collect (L l (HsForAllTy _ _ _ _)) =
const $ parseError l "Forall type not allowed as type parameter"
collect (L l (HsTyVar tv))