expander: fix 'origin on let-syntax-bound id-macro expansions

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

@@ -389,6 +389,17 @@
       (tree-map syntax-e)
       (syntax-property se 'origin))
 
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+;; Make sure `let-syntax` (which involves a rename transformer)
+;; attaches the right 'origin
+
+(test #t
+      syntax-original?
+      (let ([stx (expand #'(let-syntax ([m (lambda (stx) #''m)])
+                             m))])
+        (syntax-case stx ()
+          [(_ () (_ () e)) (car (syntax-property #'e 'origin))])))
+
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ;; #%app, etc.
 

racket/src/expander/expand/main.rkt

@@ -366,7 +366,7 @@
    ;; any expansion result
    (define post-s (maybe-add-post-expansion-scope result-s ctx))
    ;; Track expansion:
-   (define tracked-s (syntax-track-origin post-s cleaned-s id))
+   (define tracked-s (syntax-track-origin post-s cleaned-s (if (identifier? s) s (car (syntax-e s)))))
    (define rearmed-s (taint-dispatch tracked-s (lambda (t-s) (syntax-rearm t-s s)) (expand-context-phase ctx)))
    (log-expand ctx 'exit-macro rearmed-s)
    (values rearmed-s

racket/src/racket/src/startup.inc

@@ -39169,7 +39169,11 @@ static const char *startup_source =
 " id_64)))"
 "(let-values(((result-s_5)(flip-scope transformed-s_0 intro-scope_0)))"
 "(let-values(((post-s_0)(maybe-add-post-expansion-scope result-s_5 ctx_25)))"
-"(let-values(((tracked-s_0)(syntax-track-origin$1 post-s_0 cleaned-s_0 id_64)))"
+"(let-values(((tracked-s_0)"
+"(syntax-track-origin$1"
+" post-s_0"
+" cleaned-s_0"
+"(if(identifier? s_56) s_56(car(syntax-e$1 s_56))))))"
 "(let-values(((rearmed-s_0)"
 "(taint-dispatch"
 " tracked-s_0"