Avoid (most) uses of XCAR/XCDR as lvalues, for flexibility in experimenting

with lisp system changes.

1 files changed, 12 insertions, 9 deletions

diff --git a/src/lread.c b/src/lread.c
index 671305c6f93..6968c5394fb 100644
--- a/src/lread.c
+++ b/src/lread.c
@@ -832,8 +832,8 @@ Return t if file exists.")
 
   GCPRO1 (file);
   lispstream = Fcons (Qnil, Qnil);
-  XSETFASTINT (XCAR (lispstream), (EMACS_UINT)stream >> 16);
-  XSETFASTINT (XCDR (lispstream), (EMACS_UINT)stream & 0xffff);
+  XSETCARFASTINT (lispstream, (EMACS_UINT)stream >> 16);
+  XSETCDRFASTINT (lispstream, (EMACS_UINT)stream & 0xffff);
   record_unwind_protect (load_unwind, lispstream);
   record_unwind_protect (load_descriptor_unwind, load_descriptor_list);
   specbind (Qload_file_name, found);
@@ -963,16 +963,19 @@ openp (path, str, suffixes, storeptr, exec_only)
   Lisp_Object string, tail;
   int max_suffix_len = 0;
 
+  string = filename = Qnil;
+  GCPRO5 (str, string, filename, path, suffixes);
+  
   for (tail = suffixes; CONSP (tail); tail = XCDR (tail))
     {
-      CHECK_STRING (XCAR (tail), 0);
+      string = XCAR (tail);
+      CHECK_STRING (string, 0);
+      if (! EQ (string, XCAR (tail)))
+        XSETCAR (tail, string);
       max_suffix_len = max (max_suffix_len,
-                            STRING_BYTES (XSTRING (XCAR (tail))));
+                            STRING_BYTES (XSTRING (string)));
     }
 
-  string = filename = Qnil;
-  GCPRO5 (str, string, filename, path, suffixes);
-  
   if (storeptr)
     *storeptr = Qnil;
 
@@ -2724,7 +2727,7 @@ read_list (flag, readcharfun)
             {
               GCPRO2 (val, tail);
               if (!NILP (tail))
-                XCDR (tail) = read0 (readcharfun);
+                XSETCDR (tail, read0 (readcharfun));
               else
                 val = read0 (readcharfun);
               read1 (readcharfun, &ch, 0);
@@ -2817,7 +2820,7 @@ read_list (flag, readcharfun)
              ? pure_cons (elt, Qnil)
              : Fcons (elt, Qnil));
       if (!NILP (tail))
-        XCDR (tail) = tem;
+        XSETCDR (tail, tem);
       else
         val = tem;
       tail = tem;