local-expand.rkt

#lang racket

(module m1 racket
  (require (for-syntax racket/pretty))
  (define-syntax (modbeg stx)
    (syntax-case stx ()
      [(_ forms ...)
       (let ()
         (define expanded (local-expand #'(#%plain-module-begin forms ...) 'module-begin null))
         (pretty-print (syntax->datum expanded))
         (syntax-case expanded ()
           [(_ ... (quote last))
            (identifier? #'last)
            (begin (eprintf "~a\n" (syntax-local-value #'last))
                   #'(#%plain-module-begin (void)))]
           [_ #'(#%plain-module-begin (void))]))]))
  (provide (rename-out [modbeg #%module-begin])
           (except-out (all-from-out racket) #%module-begin)))

(module m2 (submod ".." m1)
  (define-syntax x (lambda (stx) #''x))
  x)