expander: fix syntax-local-bind-syntaxes for local-expand

Bind variables in a way that allows `local-expand` (with an empty stop
list) to replace a reference to the binding with one that has the same
scopes as the binding.

pkgs/racket-doc/scribblings/reference/stx-trans.scrbl

@@ -275,11 +275,15 @@ The @racket[stop-ids] argument controls how far @racket[local-expand] expands @r
 
        When @racket[#%plain-module-begin] is not in @racket[stop-ids], the
        @racket[#%plain-module-begin] transformer detects and expands sub-forms (such as
-       @racket[define-values]) regardless of the identifiers presence in @racket[stop-ids].}
+       @racket[define-values]) regardless of the identifiers presence in @racket[stop-ids].
+
+       Expansion does not replace the scopes in a local-variable
+       reference to match the binding identifier.}
 
  @item{If @racket[stop-ids] is @racket[#f] instead of a list, then @racket[stx] is expanded only as
        long as the outermost form of @racket[stx] is a macro (i.e. expansion does @emph{not} proceed
-       to sub-expressions). @racketid[#%app], @racketid[#%datum], and @racketid[#%top] identifiers are
+       to sub-expressions, and it does not replace the scopes in a local-variable reference to match the
+       binding identifier). The @racketid[#%app], @racketid[#%datum], and @racketid[#%top] identifiers are
        never introduced.}]
 
 Independent of @racket[stop-ids], when @racket[local-expand] encounters an identifier that has a local

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

@@ -2234,6 +2234,33 @@
       (expand-in-modbeg
        (m)))))
 
+;; ----------------------------------------
+;; Make sure `syntax-local-bind-syntaxes` binds variables in a way
+;; that `local-expand` replaces a use with the binding scopes.
+
+(module uses-definition-context-and-local-expand-to-replace racket/base
+  (require (for-syntax racket/base))
+
+  (define-syntax (m stx)
+    (syntax-case stx ()
+      [(_ id)
+       (let ()
+         (define intdef (syntax-local-make-definition-context))
+         (syntax-local-bind-syntaxes (list #'id)
+                                     #f ; => local variable
+                                     intdef)
+         (define raw-bind-id (internal-definition-context-introduce intdef #'id))
+         (define raw-ex-id (local-expand ((make-syntax-introducer) #'id) 'expression null intdef))
+         (define bind-id (syntax-local-identifier-as-binding raw-bind-id))
+         (define ex-id (syntax-local-identifier-as-binding raw-ex-id))
+         #`(list #,(free-identifier=? bind-id ex-id)
+                 #,(bound-identifier=? bind-id ex-id)))]))
+
+  (define result (m x))
+  (provide result))
+
+(test '(#t #t) dynamic-require ''uses-definition-context-and-local-expand-to-replace 'result)
+
 ;; ----------------------------------------
 
 (report-errs)

racket/src/expander/expand/definition-context.rkt

@@ -90,8 +90,9 @@
     (cond
      [s
       (define input-s (flip-introduction-scopes (add-intdef-scopes s all-intdefs) ctx))
-      (define tmp-env (for/fold ([env (expand-context-env ctx)]) ([sym (in-list syms)])
+      (define tmp-env (for/fold ([env (expand-context-env ctx)]) ([sym (in-list syms)]
-                        (hash-set env sym variable)))
+                                                                  [intdef-id (in-list intdef-ids)])
+                        (hash-set env sym (local-variable intdef-id))))
       (log-expand ctx 'enter-bind)
       (define vals
         (eval-for-syntaxes-binding 'syntax-local-bind-syntaxes
@@ -103,7 +104,7 @@
       (log-expand ctx 'exit-bind)
       vals]
      [else
-      (for/list ([id (in-list ids)]) variable)]))
+      (for/list ([intdef-id (in-list intdef-ids)]) (local-variable intdef-id))]))
   (define env-mixins (internal-definition-context-env-mixins intdef))
   (set-box! env-mixins (append (for/list ([intdef-id (in-list intdef-ids)]
                                           [sym (in-list syms)]