Extending the Typed Racket language creates an infinite loop

What version of Racket are you using?

v6.12

What program did you run?

File a.rkt

#lang typed/racket

(require (for-syntax racket/base))

(provide
 (rename-out [custom-module-begin #%module-begin]))

(define-syntax (custom-module-begin stx)
  (syntax-case stx ()
    [(_ _) #`(#%module-begin
              (provide x)
              (: x Integer)
              (define x 5))]))

File b.rkt

#lang s-exp "a.rkt"

aoeu

What should have happened?

The program spins in an infinite loop, consuming an unbounded amount of memory until it is terminated. The #lang racket or #lang typed/racket/no-check languages do not have this behavior.

If you got an error message, please include it here.

The dmesg command outputs:

[3981528.508682] Out of memory: Kill process 27293 (pyramidc.rkt) score 980 or sacrifice child
[3981528.510976] Killed process 27293 (pyramidc.rkt) total-vm:129313452kB, anon-rss:129152020kB, file-rss:0kB

Reproduce the infinite loop using the custom-module-begin in a.rkt and the #lang s-exp program in b.rkt, then compare it with the stated racket and typed/racket/no-check behavior. Trace the Typed Racket language-extension entry point involved in expanding b.rkt. Done means the example terminates without unbounded memory growth.