From ff5cafc77d34420b12a134ef2c1d5bd7ca4794cb Mon Sep 17 00:00:00 2001
From: Andy Wingo <wingo@pobox.com>
Date: Fri, 24 Jun 2016 17:22:17 +0200
Subject: [PATCH] Prevent (@ (ice-9 boot-9) x)

* module/ice-9/boot-9.scm: Prevent re-loading, perhaps via (@ (ice-9
  boot-9) foo).  (ice-9 boot-9) isn't a module.  Fixes #21801.
---
 module/ice-9/boot-9.scm | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/module/ice-9/boot-9.scm b/module/ice-9/boot-9.scm
index 5d1fcc4b3..c2ee108f6 100644
--- a/module/ice-9/boot-9.scm
+++ b/module/ice-9/boot-9.scm
@@ -39,6 +39,11 @@
 (eval-when (compile)
   (set-current-module (resolve-module '(guile))))
 
+;; Prevent this file being loaded more than once in a session.  Just
+;; doesn't make sense!
+(if (current-module)
+    (error "re-loading ice-9/boot-9.scm not allowed"))
+
 
 
 ;;; {Language primitives}