expander: allow rename transformer to primitive in local-expanded

Closes #2119

pkgs/racket-test-core/tests/racket/macro.rktl

@@ -2261,6 +2261,18 @@
 
 (test '(#t #t) dynamic-require ''uses-definition-context-and-local-expand-to-replace 'result)
 
+;; ----------------------------------------
+;; Check that a rename transformer mapped to a
+;; primitive is ok in the result of a local expansion
+
+(module module-begin-with-a-rename-transformer racket/base
+  (require (for-syntax racket/base))
+
+  (define-syntax m (make-rename-transformer #'#%expression))
+  
+  (begin-for-syntax
+    (local-expand #'(#%plain-module-begin (m #f)) 'module-begin '())))
+
 ;; ----------------------------------------
 
 (report-errs)

racket/src/expander/expand/main.rkt

@@ -293,7 +293,11 @@
     (define adj-s (avoid-current-expand-context (substitute-alternate-id s id) t ctx))
     (log-expand ctx 'exit-macro s)
     (expand adj-s ctx)]
-   [(expand-context-should-not-encounter-macros? ctx)
+   [(and (expand-context-should-not-encounter-macros? ctx)
+         ;; It's ok to have a rename transformer whose target
+         ;; is a primitive form, so if it's a rename transformer,
+         ;; delay the check for another step
+         (not (rename-transformer? t)))
     (raise-syntax-error #f
                         "encountered a macro binding in form that should be fully expanded"
                         s)]

racket/src/racket/src/startup.inc

@@ -39603,7 +39603,9 @@ static const char *startup_source =
 "(void)))"
 "(let-values(((adj-s186_0) adj-s_0)((ctx187_0) ctx_23))"
 "(expand9.1 #f #f #f adj-s186_0 ctx187_0))))))"
-"(if(expand-context-should-not-encounter-macros? ctx_23)"
+"(if(if(expand-context-should-not-encounter-macros? ctx_23)"
+"(not(1/rename-transformer? t_54))"
+" #f)"
 "(let-values()"
 "(raise-syntax-error$1"
 " #f"