isOpenSynTyCon tycon = isSynTyCon tycon && isOpenTyCon tycon
isDecomposableTyCon :: TyCon -> Bool
--- True iff we can deocmpose (T a b c) into ((T a b) c)
+-- True iff we can decompose (T a b c) into ((T a b) c)
-- Specifically NOT true of synonyms (open and otherwise) and coercions
isDecomposableTyCon (SynTyCon {}) = False
isDecomposableTyCon (CoTyCon {}) = False