From 6f31650539c9f06252bc1e72f322aa09da73b46d Mon Sep 17 00:00:00 2001
From: Matthew Flatt <mflatt@racket-lang.org>
Date: Mon, 30 Apr 2018 21:05:09 -0600
Subject: [PATCH] repair for re-expansion of an implicit-form expansion

The repair in 385f9588f86c56f44c26545772db6454995a7908 propagates the
must-be-bound callback too far. It shouldn't be propagated anymore after
a non-rename transformer is applied.

Closes #2048
---
 pkgs/racket-test-core/tests/racket/macro.rktl | 10 ++++++++++
 racket/src/expander/expand/main.rkt           |  6 +++---
 racket/src/racket/src/startup.inc             |  5 +++--
 3 files changed, 16 insertions(+), 5 deletions(-)

diff --git a/pkgs/racket-test-core/tests/racket/macro.rktl b/pkgs/racket-test-core/tests/racket/macro.rktl
index 8544934312..37200ba25b 100644
--- a/pkgs/racket-test-core/tests/racket/macro.rktl
+++ b/pkgs/racket-test-core/tests/racket/macro.rktl
@@ -1950,6 +1950,16 @@
                  (let-syntax ([#%datum (make-rename-transformer #'unbound)])
                    (+ 1 2))))
 
+(module make-sure-not-bound-as-syntax-is-not-propagated-to-reexpansion racket/base
+  (module new-top racket/base
+    (provide #%top)
+    (define (helper sym) sym)
+    (define-syntax-rule (#%top . ID)
+      (helper 'ID)))
+  
+  (local-require (submod 'new-top))
+  foobar)
+
 ;; ----------------------------------------
 ;; Check that definition context bindings are made available when the context is provided as fourth
 ;; argument of syntax-local-bind-syntaxes
diff --git a/racket/src/expander/expand/main.rkt b/racket/src/expander/expand/main.rkt
index ca2f9b03bd..d6c1f61888 100644
--- a/racket/src/expander/expand/main.rkt
+++ b/racket/src/expander/expand/main.rkt
@@ -128,10 +128,10 @@
    (cond
      [(eq? binding 'ambiguous)
       (when fail-non-transformer (fail-non-transformer))
-     (raise-ambiguous-error id ctx)]
+      (raise-ambiguous-error id ctx)]
      [(not binding)
       (when fail-non-transformer (fail-non-transformer))
-     ;; The `#%app` binding might do something with unbound ids
+      ;; The `#%app` binding might do something with unbound ids
       (expand-implicit '#%app (substitute-alternate-id s alternate-id) ctx id)]
     [else
      ;; Find out whether it's bound as a variable, syntax, or core form
@@ -322,7 +322,7 @@
                                                             id))
                    #:skip-log? (or (expand-context-only-immediate? ctx)
                                    (rename-transformer? t))
-                   #:fail-non-transformer fail-non-transformer)])]))
+                   #:fail-non-transformer (and (rename-transformer? t) fail-non-transformer))])]))
 
 ;; Handle the expansion of a variable to itself
 (define (dispatch-variable t s id ctx binding primitive? protected?)
diff --git a/racket/src/racket/src/startup.inc b/racket/src/racket/src/startup.inc
index 49ff052816..f958d84c18 100644
--- a/racket/src/racket/src/startup.inc
+++ b/racket/src/racket/src/startup.inc
@@ -39985,11 +39985,12 @@ static const char *startup_source =
 "(let-values(((or-part_263)"
 "(expand-context-only-immediate? ctx_23)))"
 "(if or-part_263 or-part_263(1/rename-transformer? t_53))))"
-"((fail-non-transformer199_0) fail-non-transformer_4))"
+"((temp199_0)"
+"(if(1/rename-transformer? t_53) fail-non-transformer_4 #f)))"
 "(expand9.1"
 " temp197_0"
 " #t"
-" fail-non-transformer199_0"
+" temp199_0"
 " #t"
 " temp198_0"
 " #t"