[perl #3112] Stop last from returning values

In push @a, last, it can try to return the @a, copying it like a sca-
lar in the process, resulting in Bizarre copy of ARRAY in last.

In do{{&{sub{"Just another Perl hacker,\n"}},last}}, it returns "Just
another Perl hacker,\n".

The former is clearly a bug.  The latter depends on a side-effect of
the same bug.

‘last’ really should not be trying to return the values that the same
statement has accumulated so far.

1 files changed, 1 insertions, 3 deletions

diff --git a/pp_ctl.c b/pp_ctl.c
index 2144fab86d..63482fd194 100644
--- a/pp_ctl.c
+++ b/pp_ctl.c
@@ -2616,7 +2616,6 @@ PP(pp_last)
 
     POPBLOCK(cx,newpm);
     cxstack_ix++; /* temporarily protect top context */
-    mark = newsp;
     switch (CxTYPE(cx)) {
     case CXt_LOOP_LAZYIV:
     case CXt_LOOP_LAZYSV:
@@ -2643,8 +2642,7 @@ PP(pp_last)
     }
 
     TAINT_NOT;
-    PL_stack_sp = adjust_stack_on_leave(newsp, PL_stack_sp, MARK, gimme,
-				pop2 == CXt_SUB ? SVs_TEMP : 0);
+    PL_stack_sp = newsp;
 
     LEAVE;
     cxstack_ix--;