[racket-dev] Unable to expand cross-phase persistent module

Running `expand` on the module defined in `racket/tcp` errors.

In transcript form:

-> (define p (open-input-file
"/home/samth/sw/plt/racket/collects/racket/tcp.rkt"))
-> (define mod (read-syntax (object-name p) p))
-> (parameterize ([current-namespace (make-base-namespace)])
     (expand (namespace-syntax-introduce mod)))
; /home/samth/sw/plt/racket/collects/racket/tcp.rkt::2: module: cannot be
;   cross-phase persistent due to required modules
;   in: (#%module-begin (#%require (all-except (quote #%network) tcp-addresses)
;     (rename (quote #%network) c:tcp-addresses tcp-addresses)) (#%provide
;     tcp-connect tcp-connect/enable-break tcp-listen tcp-close
;     tcp-accept-ready? tcp-accept tcp-accept-evt tcp-accept...
; [,bt for context]

I don't know why it would do this. The same thing happens with the
minimal module that's declared cross-phase persistent.

Sam