extend stack on scalar empty list slice

In scalar context, an empty list slice returns PL_sv_undef.
Extned the stack for this return value, since if there were no elements
or indices, nothing was popped from the stack

1 files changed, 1 insertions, 0 deletions

diff --git a/pp.c b/pp.c
index 6be3e783ee..768eb7d82a 100644
--- a/pp.c
+++ b/pp.c
@@ -5209,6 +5209,7 @@ PP(pp_lslice)
 
     if (GIMME_V != G_ARRAY) {
         if (lastlelem < firstlelem) {
+            EXTEND(SP, 1);
             *firstlelem = &PL_sv_undef;
         }
         else {