From 4c8917c4284a3e269bfd4e3594770e05d2b49f4e Mon Sep 17 00:00:00 2001
From: Matthew Flatt <mflatt@racket-lang.org>
Date: Sat, 9 Jul 2005 13:19:14 +0000
Subject: [PATCH] fixed assignment in sub-struct with immutable field

svn: r369
---
 src/mzscheme/src/struct.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/src/mzscheme/src/struct.c b/src/mzscheme/src/struct.c
index 2c570dda8c..e4fc74fe77 100644
--- a/src/mzscheme/src/struct.c
+++ b/src/mzscheme/src/struct.c
@@ -1089,11 +1089,12 @@ static Scheme_Object *struct_setter(Struct_Proc_Info *i, int argc, Scheme_Object
 
   if (i->struct_type->immutables) {
     Scheme_Struct_Type *t = i->struct_type;
+    int p = pos;
 
     if (t->name_pos)
-      pos -= t->parent_types[t->name_pos - 1]->num_slots;
+      p -= t->parent_types[t->name_pos - 1]->num_slots;
     
-    if (t->immutables[pos]) {
+    if (t->immutables[p]) {
       scheme_arg_mismatch(i->func_name, 
 			  "cannot modify value of immutable field in structure: ", 
 			  args[0]);