fix problem in `free-identifier=?'

Renamings created by a rename-transformer binding were not treated
correctly by `free-identifier=?'.

Closes PR 12623

collects/tests/racket/macro.rktl

@@ -853,6 +853,68 @@
   (eval '(def t))
   (eval '(t)))
 
+;; ----------------------------------------
+;; Check that a `free-identifier=?' mapping via a rename transformer
+;; doesn't mess up a `free-identifier=?' test where the relevant
+;; identifier is shadowed with a lexical binding; this test was
+;; provided by Carl Eastlund.
+
+(module lang-for-identifier=?-test racket/base
+  (#%module-begin
+
+    (provide
+      #%module-begin
+      (all-from-out racket/base)
+      (for-syntax
+        (all-from-out racket/base)
+        (all-from-out syntax/parse)))
+
+    (require
+      (for-syntax
+        racket/base
+        syntax/parse))
+
+    (define-syntax (#%module-begin stx)
+      (syntax-parse stx
+        [(_ before ...)
+         (syntax-parse (local-expand
+                         #'(#%plain-module-begin before ...)
+                         'module-begin
+                         '())
+           #:literal-sets {kernel-literals}
+           [(#%plain-module-begin
+              _
+              _
+              (#%plain-lambda {one:id}
+                (letrec-syntaxes+values _ _ two:id)))
+            
+            (let ()
+              (when (bound-identifier=? #'one #'two)
+                (unless (free-identifier=? #'one #'two)
+                  (error 'bug
+                         "{bound,free}-identifier=? inconsistency")))
+              
+              #'(#%plain-module-begin))])]))))
+
+(module consistency-of-identifier=?-test 'lang-for-identifier=?-test
+  (#%module-begin
+
+    (define-syntaxes {lam}
+      (lambda (stx)
+        (syntax-parse stx
+          [(_ unmarked . body)
+           (define/syntax-parse marked
+             (syntax-local-introduce (attribute unmarked)))
+           #'(#%plain-lambda {marked}
+               (define-syntaxes {unmarked}
+                 (make-rename-transformer #'marked))
+               . body)])))
+
+    (define-syntaxes {x}
+      (make-rename-transformer #'dummy))
+
+    (lam x x)))
+
 ;; ----------------------------------------
 
 (report-errs)

src/racket/src/syntax.c

@@ -4437,8 +4437,9 @@ static Scheme_Object *get_module_src_name(Scheme_Object *a, Scheme_Object *orig_
   Scheme_Object *bdg = NULL;
 
   result = ((Scheme_Stx *)a)->u.modinfo_cache;
-  if (result && SAME_OBJ(phase, scheme_make_integer(0)))
+  if (result && SAME_OBJ(phase, scheme_make_integer(0))) {
     return result;
+  }
 
   WRAP_POS_INIT(wraps, ((Scheme_Stx *)a)->wraps);
 
@@ -4458,7 +4459,7 @@ static Scheme_Object *get_module_src_name(Scheme_Object *a, Scheme_Object *orig_
 	result = SCHEME_STX_VAL(a);
 
 #if 0
-      printf("%p %p %s (%d) %d %p\n", 
+      printf("%p %p %s (%d) %d %p\n",
              a, orig_phase, SCHEME_SYMBOLP(result) ? SCHEME_SYM_VAL(result) : "!?", 
              can_cache, sealed, free_id_recur);
 #endif 
@@ -4563,7 +4564,10 @@ static Scheme_Object *get_module_src_name(Scheme_Object *a, Scheme_Object *orig_
             if (SCHEME_BOXP(rename)) {
               /* only happens with free_id_renames */
               rename = SCHEME_BOX_VAL(rename);
-              result = SCHEME_CAR(rename);
+              if (no_lexical || SCHEME_TRUEP(SCHEME_CDR(rename)))
+                result = SCHEME_CAR(rename);
+              else
+                rename = NULL;
             } else if (SCHEME_PAIRP(rename)) {
 	      if (nom_mod_p(rename)) {
 		result = glob_id;