record_dfun_usage dfun_id
= do { hsc_env <- getTopEnv
; let dfun_name = idName dfun_id
- dfun_mod = nameModule dfun_name
+ dfun_mod = ASSERT( isExternalName dfun_name )
+ nameModule dfun_name
; if isInternalName dfun_name || -- Internal name => defined in this module
modulePackageId dfun_mod /= thisPackage (hsc_dflags hsc_env)
then return () -- internal, or in another package