Don't localise array / hash slice ref assignment

RT #133538

The experimental ref assignment aliasing feature, when applied to
array or hash slices, was treating the slice as if it was always localized;
e.g.

    \(@a[3,5,7]) = \(....);

was being interpreted as

    local \(@a[3,5,7]) = \(....);

The fix is simple: check for the OPpLVAL_INTRO flag actually being set
on the op, rather than unconditionally localising the array/hash
elements.

1 files changed, 6 insertions, 4 deletions

diff --git a/pp.c b/pp.c
index cfa343fbbb..6d432acd31 100644
--- a/pp.c
+++ b/pp.c
@@ -6599,10 +6599,12 @@ PP(pp_lvrefslice)
 
     while (++MARK <= SP) {
 	SV * const elemsv = *MARK;
-	if (SvTYPE(av) == SVt_PVAV)
-	    S_localise_aelem_lval(aTHX_ av, elemsv, can_preserve);
-	else
-	    S_localise_helem_lval(aTHX_ (HV *)av, elemsv, can_preserve);
+        if (UNLIKELY(localizing)) {
+            if (SvTYPE(av) == SVt_PVAV)
+                S_localise_aelem_lval(aTHX_ av, elemsv, can_preserve);
+            else
+                S_localise_helem_lval(aTHX_ (HV *)av, elemsv, can_preserve);
+        }
 	*MARK = sv_2mortal(newSV_type(SVt_PVMG));
 	sv_magic(*MARK,(SV *)av,PERL_MAGIC_lvref,(char *)elemsv,HEf_SVKEY);
     }