toIfaceType ext (TyConApp tc tys) = IfaceTyConApp (mkIfaceTc ext tc) (toIfaceTypes ext tys)
toIfaceType ext (ForAllTy tv t) = IfaceForAllTy (toIfaceTvBndr tv) (toIfaceType ext t)
toIfaceType ext (PredTy st) = IfacePredTy (toIfacePred ext st)
-toIfaceType ext (NoteTy (SynNote tc_app) ty) = toIfaceType ext tc_app
+toIfaceType ext (NoteTy (SynNote tc_app) ty) = toIfaceType ext tc_app -- Retain synonyms
toIfaceType ext (NoteTy other_note ty) = toIfaceType ext ty
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