less: symbolic arguments: fix crash and incorrectness.

* lib.c (less): We cannot direclty access right->s.package
because the right operand can be nil. This causes a crash.
Furthermore, the separate NIL case is wrong. If the left
object is nil, the same logic must be carried out as for SYM.
The opposite operand might have the same name, and so packages
have to be compared. We simply merge the two cases, and make
sure we use the proper accessors symbol_name and
symbol_package to avoid blowing up on nil.

1 files changed, 3 insertions, 4 deletions

diff --git a/lib.c b/lib.c
index 6b13be82..0fdc8ef0 100644
--- a/lib.c
+++ b/lib.c
@@ -6227,17 +6227,16 @@ tail:
   case LSTR:
     return str_lt(left, right);
   case NIL:
-    return str_lt(nil_string, symbol_name(right));
   case SYM:
     {
-      val cmp = cmp_str(left->s.name, symbol_name(right));
+      val cmp = cmp_str(symbol_name(left), symbol_name(right));
       if (cmp == negone) {
         return t;
       } else if (cmp == one) {
         return nil;
       } else {
-        val lpkg = left->s.package;
-        val rpkg = right->s.package;
+        val lpkg = symbol_package(left);
+        val rpkg = symbol_package(right);
 
         if (lpkg == nil && rpkg == nil)
           return tnil(left < right);