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Implement foreach on lvref lexical without magic #24202

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Implement foreach on lvref lexical without magic #24202

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773e491
Split tests for B::Deparse refaliasing into two sections
leonerd Feb 16, 2026
755e534
Implement `foreach \LEXICAL (...)` without lvref magic
leonerd Feb 16, 2026
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2 changes: 1 addition & 1 deletion cop.h
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Original file line number Diff line number Diff line change
Expand Up @@ -1166,7 +1166,7 @@ struct context {
/* this is only set in conjunction with CXp_FOR_GV */
#define CXp_FOR_DEF 0x10 /* foreach using $_ */
/* these 3 are mutually exclusive */
#define CXp_FOR_LVREF 0x20 /* foreach using \$var */
#define CXp_FOR_LVREF 0x20 /* foreach using \our $var */
#define CXp_FOR_GV 0x40 /* foreach using package var */
#define CXp_FOR_PAD 0x80 /* foreach using lexical var */

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56 changes: 24 additions & 32 deletions inline.h
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Expand Up @@ -4317,43 +4317,35 @@ Perl_cx_poploop(pTHX_ PERL_CONTEXT *cx)
MAGIC *mg = SvMAGIC(itervar);
assert(mg);
assert(mg->mg_type == PERL_MAGIC_lvref);
if (!mg->mg_obj) {
// LV ref around a lexical, mg_len gives its pad index
SV **padslot = &PAD_SVl(mg->mg_len);
SV *oldsv = *padslot;
*padslot = origval;
SvREFCNT_dec(oldsv);
}
else {
// LV ref around a package lexical, mg_obj gives its GV
GV *gv = (GV *)mg->mg_obj;
SV *oldsv = NULL;
switch(mg->mg_private & OPpLVREF_TYPE) {
case OPpLVREF_SV:
oldsv = GvSVn(gv);
GvSVn(gv) = origval;
break;
assert(mg->mg_obj);
// LV ref around a package lexical, mg_obj gives its GV
GV *gv = (GV *)mg->mg_obj;
SV *oldsv = NULL;
switch(mg->mg_private & OPpLVREF_TYPE) {
case OPpLVREF_SV:
oldsv = GvSVn(gv);
GvSVn(gv) = origval;
break;

case OPpLVREF_AV:
oldsv = (SV *)GvAV(gv);
GvAV(gv) = (AV *)origval;
break;
case OPpLVREF_AV:
oldsv = (SV *)GvAV(gv);
GvAV(gv) = (AV *)origval;
break;

case OPpLVREF_HV:
oldsv = (SV *)GvHV(gv);
GvHV(gv) = (HV *)origval;
break;
case OPpLVREF_HV:
oldsv = (SV *)GvHV(gv);
GvHV(gv) = (HV *)origval;
break;

case OPpLVREF_CV:
oldsv = (SV *)GvCV(gv);
GvCV_set(gv, (CV *)origval);
break;
case OPpLVREF_CV:
oldsv = (SV *)GvCV(gv);
GvCV_set(gv, (CV *)origval);
break;

default:
NOT_REACHED;
}
SvREFCNT_dec(oldsv);
default:
NOT_REACHED;
}
SvREFCNT_dec(oldsv);
}
if (cx->cx_type & (CXp_FOR_GV|CXp_FOR_LVREF))
SvREFCNT_dec(cx->blk_loop.itervar_u.svp);
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94 changes: 49 additions & 45 deletions lib/B/Deparse.t
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Expand Up @@ -2622,51 +2622,6 @@ my %h;
$_ == 3 ? \$_ : $_ = \3;
$_ == 3 ? \$_ : \$x = \3;
\($_ == 3 ? $_ : $x) = \3;
for \my $topic (\$1, \$2) {
die;
}
for \state $topic (\$1, \$2) {
die;
}
for \our $topic (\$1, \$2) {
die;
}
for \$_ (\$1, \$2) {
die;
}
for \my @a ([1,2], [3,4]) {
die;
}
for \state @a ([1,2], [3,4]) {
die;
}
for \our @a ([1,2], [3,4]) {
die;
}
for \@_ ([1,2], [3,4]) {
die;
}
for \my %a ({5,6}, {7,8}) {
die;
}
for \our %a ({5,6}, {7,8}) {
die;
}
for \state %a ({5,6}, {7,8}) {
die;
}
for \%_ ({5,6}, {7,8}) {
die;
}
{
my sub a;
for \&a (sub { 9; }, sub { 10; }) {
die;
}
}
for \&a (sub { 9; }, sub { 10; }) {
die;
}
>>>>
our $x;
\$x = \$x;
Expand Down Expand Up @@ -2745,6 +2700,55 @@ my %h;
$_ == 3 ? \$_ : $_ = \3;
$_ == 3 ? \$_ : \$x = \3;
($_ == 3 ? \$_ : \$x) = \3;
####
# lvalue reference iteration
# CONTEXT use feature "state", 'refaliasing', 'lexical_subs'; no warnings 'experimental';
for \my $topic (\$1, \$2) {
die;
}
for \state $topic (\$1, \$2) {
die;
}
for \our $topic (\$1, \$2) {
die;
}
for \$_ (\$1, \$2) {
die;
}
for \my @a ([1,2], [3,4]) {
die;
}
for \state @a ([1,2], [3,4]) {
die;
}
for \our @a ([1,2], [3,4]) {
die;
}
for \@_ ([1,2], [3,4]) {
die;
}
for \my %a ({5,6}, {7,8}) {
die;
}
for \our %a ({5,6}, {7,8}) {
die;
}
for \state %a ({5,6}, {7,8}) {
die;
}
for \%_ ({5,6}, {7,8}) {
die;
}
{
my sub a;
for \&a (sub { 9; }, sub { 10; }) {
die;
}
}
for \&a (sub { 9; }, sub { 10; }) {
die;
}
>>>>
foreach \my $topic (\$1, \$2) {
die;
}
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7 changes: 5 additions & 2 deletions op.c
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Expand Up @@ -10086,11 +10086,14 @@ Perl_newFOROP(pTHX_ I32 flags, OP *sv, OP *expr, OP *block, OP *cont)
varop->op_type == OP_PADAV ||
varop->op_type == OP_PADHV));

if(varop->op_type != OP_LVREF || varop->op_private & OPpLVAL_INTRO) { /* for my \VAR */
/* Any of these ops with a non-zero ->op_targ operates on lexicals
* providing it is not OPf_STACKED */
if((varop->op_targ && !(varop->op_flags & OPf_STACKED)) || varop->op_private & OPpLVAL_INTRO) { /* for my \VAR */
/* Throw away the sv op subtree and turn this into a simple
* padoffset + OPpITER_REFALIAS flag */
iterpflags = OPpITER_REFALIAS;
enteriterpflags = OPpLVAL_INTRO;
if(varop->op_private & OPpLVAL_INTRO)
enteriterpflags = OPpLVAL_INTRO;
padoff = varop->op_targ;
varop->op_targ = 0;
op_free(sv);
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25 changes: 10 additions & 15 deletions pp_ctl.c
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Original file line number Diff line number Diff line change
Expand Up @@ -2627,22 +2627,17 @@ PP(pp_enteriter)
MAGIC *mg = SvMAGIC(sv);
assert(mg);
assert(mg->mg_type == PERL_MAGIC_lvref);
if (!mg->mg_obj) {
// LV ref around a lexical, mg_len gives its pad index
itersave = SvREFCNT_inc_NN(PAD_SV(mg->mg_len));
}
else {
// LV ref around a package lexical, mg_obj gives its GV
GV *gv = (GV *)mg->mg_obj;
assert(SvTYPE(gv) == SVt_PVGV);
switch(mg->mg_private & OPpLVREF_TYPE) {
case OPpLVREF_SV: itersave = GvSVn(gv); break;
case OPpLVREF_AV: itersave = (SV *)GvAV(gv); break;
case OPpLVREF_HV: itersave = (SV *)GvHV(gv); break;
case OPpLVREF_CV: itersave = (SV *)GvCV(gv); break;
}
SvREFCNT_inc_void(itersave);
assert(mg->mg_obj);
// LV ref around a package lexical, mg_obj gives its GV
GV *gv = (GV *)mg->mg_obj;
assert(SvTYPE(gv) == SVt_PVGV);
switch(mg->mg_private & OPpLVREF_TYPE) {
case OPpLVREF_SV: itersave = GvSVn(gv); break;
case OPpLVREF_AV: itersave = (SV *)GvAV(gv); break;
case OPpLVREF_HV: itersave = (SV *)GvHV(gv); break;
case OPpLVREF_CV: itersave = (SV *)GvCV(gv); break;
}
SvREFCNT_inc_void(itersave);
cxflags = CXp_FOR_LVREF;
}
/* we transfer ownership of 1 ref count of itervarp from the stack
Expand Down
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