+isBottomingId id = isBottomingSig (idNewStrictness id)
+
+idNewStrictness_maybe :: Id -> Maybe StrictSig
+idNewStrictness :: Id -> StrictSig
+
+idNewStrictness_maybe id = newStrictnessInfo (idInfo id)
+idNewStrictness id = idNewStrictness_maybe id `orElse` topSig
+
+setIdNewStrictness :: Id -> StrictSig -> Id
+setIdNewStrictness id sig = modifyIdInfo (`setNewStrictnessInfo` Just sig) id
+
+zapIdNewStrictness :: Id -> Id
+zapIdNewStrictness id = modifyIdInfo (`setNewStrictnessInfo` Nothing) id
+
+ ---------------------------------
+ -- TYPE GENERALISATION
+idTyGenInfo :: Id -> TyGenInfo
+idTyGenInfo id = tyGenInfo (idInfo id)
+
+setIdTyGenInfo :: Id -> TyGenInfo -> Id
+setIdTyGenInfo id tygen_info = modifyIdInfo (`setTyGenInfo` tygen_info) id