fix `syntax-local-get-shadower' for submodules

Closes PR 12926, 12928

Merge to v5.3

collects/tests/racket/package.rktl

@@ -247,6 +247,22 @@
  (open-package p5)
  q)
 
+;; ----------------------------------------
+;; In a submodule
+
+(module package-in-a-submodule racket/base
+  (require racket/package)
+  
+  (define-package pkg (foo)
+    (define foo 5))
+  
+  (module+ main
+    (open-package pkg)
+    (define out foo)
+    (provide out)))
+
+(test 5 dynamic-require '(submod 'package-in-a-submodule main) 'out)
+
 ;; ----------------------------------------
 
 (report-errs)

collects/tests/racket/submodule.rktl

@@ -761,7 +761,6 @@
           (provide v)))))
   (test 130 dynamic-require `(submod ,path main) 'v))
 
-
 ;; ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 
 (report-errs)

collects/tests/racket/unitsig.rktl

@@ -714,6 +714,27 @@
 	(list (signature->symbols s^))
 	(list (list))))
 
+;; ----------------------------------------
+;; In a submodule
+
+(module unit-in-a-submodule racket/base
+  (require racket/unit)
+
+  (define-signature foo^ (f))
+  
+  (module+ main
+    (define-unit foo@
+      (import)
+      (export foo^)
+      
+      (define f (lambda (x) x)))
+    (define-values/invoke-unit/infer foo@)
+
+    (define out (f 50))
+    (provide out)))
+
+(test 50 dynamic-require '(submod 'unit-in-a-submodule main) 'out)
+
 ;; --------------------------------------------------
 
 (report-errs)

src/racket/src/env.c

@@ -2232,6 +2232,16 @@ local_module_introduce(int argc, Scheme_Object *argv[])
 
   v = scheme_stx_source_module(s, 0, 0);
   if (SCHEME_FALSEP(v)) {
+    if (env->genv->module
+        && env->genv->module->rn_stx
+        && SCHEME_VECTORP(env->genv->module->rn_stx)) {
+      /* This is a submodule, and `rn_stx' has renames for the enclosing modules */
+      int i;
+      for (i = SCHEME_VEC_SIZE(env->genv->module->rn_stx); i-- > 1; ) {
+        v = SCHEME_VEC_ELS(env->genv->module->rn_stx)[i];
+        s = scheme_add_rename(s, scheme_stx_to_rename(v));
+      }
+    }
     if (env->genv->rename_set)
       s = scheme_add_rename(s, env->genv->rename_set);
     if (env->genv->post_ex_rename_set)