, notNull arg_bndrs -- Only specialise functions
, Just all_calls <- lookupVarEnv bind_calls fn
= do { (boring_call, pats) <- callsToPats env specs arg_occs all_calls
, notNull arg_bndrs -- Only specialise functions
, Just all_calls <- lookupVarEnv bind_calls fn
= do { (boring_call, pats) <- callsToPats env specs arg_occs all_calls