BEGIN { chdir 't' if -d 't'; @INC = '../lib'; require './test.pl'; } plan tests=>187; sub a : lvalue { my $a = 34; ${\(bless \$a)} } # Return a temporary sub b : lvalue { ${\shift} } my $out = a(b()); # Check that temporaries are allowed. is(ref $out, 'main'); # Not reached if error. my @out = grep /main/, a(b()); # Check that temporaries are allowed. cmp_ok(scalar @out, '==', 1); # Not reached if error. my $in; # Check that we can return localized values from subroutines: sub in : lvalue { $in = shift; } sub neg : lvalue { #(num_str) return num_str local $_ = shift; s/^\+/-/; $_; } in(neg("+2")); is($in, '-2'); sub get_lex : lvalue { $in } sub get_st : lvalue { $blah } sub id : lvalue { ${\shift} } sub id1 : lvalue { $_[0] } sub inc : lvalue { ${\++$_[0]} } $in = 5; $blah = 3; get_st = 7; cmp_ok($blah, '==', 7); get_lex = 7; cmp_ok($in, '==', 7); ++get_st; cmp_ok($blah, '==', 8); ++get_lex; cmp_ok($in, '==', 8); id(get_st) = 10; cmp_ok($blah, '==', 10); id(get_lex) = 10; cmp_ok($in, '==', 10); ++id(get_st); cmp_ok($blah, '==', 11); ++id(get_lex); cmp_ok($in, '==', 11); id1(get_st) = 20; cmp_ok($blah, '==', 20); id1(get_lex) = 20; cmp_ok($in, '==', 20); ++id1(get_st); cmp_ok($blah, '==', 21); ++id1(get_lex); cmp_ok($in, '==', 21); inc(get_st); cmp_ok($blah, '==', 22); inc(get_lex); cmp_ok($in, '==', 22); inc(id(get_st)); cmp_ok($blah, '==', 23); inc(id(get_lex)); cmp_ok($in, '==', 23); ++inc(id1(id(get_st))); cmp_ok($blah, '==', 25); ++inc(id1(id(get_lex))); cmp_ok($in, '==', 25); @a = (1) x 3; @b = (undef) x 2; $#c = 3; # These slots are not fillable. # Explanation: empty slots contain &sv_undef. =for disabled constructs sub a3 :lvalue {@a} sub b2 : lvalue {@b} sub c4: lvalue {@c} $_ = ''; eval <<'EOE' or $_ = $@; ($x, a3, $y, b2, $z, c4, $t) = (34 .. 78); 1; EOE #@out = ($x, a3, $y, b2, $z, c4, $t); #@in = (34 .. 41, (undef) x 4, 46); #print "# '@out' ne '@in'\nnot " unless "@out" eq "@in"; like($_, qr/Can\'t return an uninitialized value from lvalue subroutine/); print "ok 22\n"; =cut my $var; sub a::var : lvalue { $var } "a"->var = 45; cmp_ok($var, '==', 45); my $oo; $o = bless \$oo, "a"; $o->var = 47; cmp_ok($var, '==', 47); sub o : lvalue { $o } o->var = 49; cmp_ok($var, '==', 49); sub nolv () { $x0, $x1 } # Not lvalue $_ = ''; eval <<'EOE' or $_ = $@; nolv = (2,3); 1; EOE like($_, qr/Can\'t modify non-lvalue subroutine call in scalar assignment/); $_ = ''; eval <<'EOE' or $_ = $@; nolv = (2,3) if $_; 1; EOE like($_, qr/Can\'t modify non-lvalue subroutine call in scalar assignment/); $_ = ''; eval <<'EOE' or $_ = $@; &nolv = (2,3) if $_; 1; EOE like($_, qr/Can\'t modify non-lvalue subroutine call in scalar assignment/); $x0 = $x1 = $_ = undef; $nolv = \&nolv; eval <<'EOE' or $_ = $@; $nolv->() = (2,3) if $_; 1; EOE ok(!defined $_) or diag "'$_', '$x0', '$x1'"; $x0 = $x1 = $_ = undef; $nolv = \&nolv; eval <<'EOE' or $_ = $@; $nolv->() = (2,3); 1; EOE like($_, qr/Can\'t modify non-lvalue subroutine call/) or diag "'$_', '$x0', '$x1'"; sub lv0 : lvalue { } sub rlv0 : lvalue { return } $_ = undef; eval <<'EOE' or $_ = $@; lv0 = (2,3); 1; EOE like($_, qr/Can't return undef from lvalue subroutine/); $_ = undef; eval <<'EOE' or $_ = $@; rlv0 = (2,3); 1; EOE like($_, qr/Can't return undef from lvalue subroutine/, 'explicit return of nothing in scalar context'); $_ = undef; eval <<'EOE' or $_ = $@; (lv0) = (2,3); 1; EOE ok(!defined $_) or diag $_; $_ = undef; eval <<'EOE' or $_ = $@; (rlv0) = (2,3); 1; EOE ok(!defined $_, 'explicit return of nothing in list context') or diag $_; ($a,$b)=(); (lv0($a,$b)) = (3,4); is +($a//'undef') . ($b//'undef'), 'undefundef', 'list assignment to empty lvalue sub'; sub lv1u :lvalue { undef } sub rlv1u :lvalue { undef } $_ = undef; eval <<'EOE' or $_ = $@; lv1u = (2,3); 1; EOE like($_, qr/Can't return undef from lvalue subroutine/); $_ = undef; eval <<'EOE' or $_ = $@; rlv1u = (2,3); 1; EOE like($_, qr/Can't return undef from lvalue subroutine/, 'explicitly returning undef in scalar context'); $_ = undef; eval <<'EOE' or $_ = $@; (lv1u) = (2,3); 1; EOE ok(!defined, 'implicitly returning undef in list context'); $_ = undef; eval <<'EOE' or $_ = $@; (rlv1u) = (2,3); 1; EOE ok(!defined, 'explicitly returning undef in list context'); $x = '1234567'; $_ = undef; eval <<'EOE' or $_ = $@; sub lv1t : lvalue { index $x, 2 } lv1t = (2,3); 1; EOE like($_, qr/Can\'t return a temporary from lvalue subroutine/); $_ = undef; eval <<'EOE' or $_ = $@; sub rlv1t : lvalue { index $x, 2 } rlv1t = (2,3); 1; EOE like($_, qr/Can\'t return a temporary from lvalue subroutine/, 'returning a PADTMP explicitly'); $_ = undef; eval <<'EOE' or $_ = $@; (rlv1t) = (2,3); 1; EOE like($_, qr/Can\'t return a temporary from lvalue subroutine/, 'returning a PADTMP explicitly (list context)'); $_ = undef; sub lv2t : lvalue { shift } (lv2t($_)) = (2,3); is($_, 2); $xxx = 'xxx'; sub xxx () { $xxx } # Not lvalue $_ = undef; eval <<'EOE' or $_ = $@; sub lv1tmp : lvalue { xxx } # is it a TEMP? lv1tmp = (2,3); 1; EOE like($_, qr/Can\'t modify non-lvalue subroutine call at /); $_ = undef; eval <<'EOE' or $_ = $@; (lv1tmp) = (2,3); 1; EOE like($_, qr/Can\'t modify non-lvalue subroutine call at /); sub yyy () { 'yyy' } # Const, not lvalue $_ = undef; eval <<'EOE' or $_ = $@; sub lv1tmpr : lvalue { yyy } # is it read-only? lv1tmpr = (2,3); 1; EOE like($_, qr/Can\'t return a readonly value from lvalue subroutine at/); $_ = undef; eval <<'EOE' or $_ = $@; (lv1tmpr) = (2,3); 1; EOE like($_, qr/Can\'t return a readonly value from lvalue subroutine/); sub lva : lvalue {@a} $_ = undef; @a = (); $a[1] = 12; eval <<'EOE' or $_ = $@; (lva) = (2,3); 1; EOE is("'@a' $_", "'2 3' "); $_ = undef; @a = (); $a[0] = undef; $a[1] = 12; eval <<'EOE' or $_ = $@; (lva) = (2,3); 1; EOE is("'@a' $_", "'2 3' "); is lva->${\sub { return $_[0] }}, 2, 'lvalue->$thing when lvalue returns array'; my @my = qw/ a b c /; sub lvmya : lvalue { @my } is lvmya->${\sub { return $_[0] }}, 3, 'lvalue->$thing when lvalue returns lexical array'; sub lv1n : lvalue { $newvar } $_ = undef; eval <<'EOE' or $_ = $@; lv1n = (3,4); 1; EOE is("'$newvar' $_", "'4' "); sub lv1nn : lvalue { $nnewvar } $_ = undef; eval <<'EOE' or $_ = $@; (lv1nn) = (3,4); 1; EOE is("'$nnewvar' $_", "'3' "); $a = \&lv1nn; $a->() = 8; is($nnewvar, '8'); eval 'sub AUTOLOAD : lvalue { $newvar }'; foobar() = 12; is($newvar, "12"); # But autoloading should only be triggered by a call to an undefined # subroutine. &{"lv1nn"} = 14; is $newvar, 12, 'AUTOLOAD does not take precedence over lvalue sub'; eval { &{"xxx"} = 14 }; is $newvar, 12, 'AUTOLOAD does not take precedence over non-lvalue sub'; { my %hash; my @array; sub alv : lvalue { $array[1] } sub alv2 : lvalue { $array[$_[0]] } sub hlv : lvalue { $hash{"foo"} } sub hlv2 : lvalue { $hash{$_[0]} } $array[1] = "not ok 51\n"; alv() = "ok 50\n"; is(alv(), "ok 50\n"); alv2(20) = "ok 51\n"; is($array[20], "ok 51\n"); $hash{"foo"} = "not ok 52\n"; hlv() = "ok 52\n"; is($hash{foo}, "ok 52\n"); $hash{bar} = "not ok 53\n"; hlv("bar") = "ok 53\n"; is(hlv("bar"), "ok 53\n"); sub array : lvalue { @array } sub array2 : lvalue { @array2 } # This is a global. sub hash : lvalue { %hash } sub hash2 : lvalue { %hash2 } # So's this. @array2 = qw(foo bar); %hash2 = qw(foo bar); (array()) = qw(ok 54); is("@array", "ok 54"); (array2()) = qw(ok 55); is("@array2", "ok 55"); (hash()) = qw(ok 56); cmp_ok($hash{ok}, '==', 56); (hash2()) = qw(ok 57); cmp_ok($hash2{ok}, '==', 57); @array = qw(a b c d); sub aslice1 : lvalue { @array[0,2] }; (aslice1()) = ("ok", "already"); is("@array", "ok b already d"); @array2 = qw(a B c d); sub aslice2 : lvalue { @array2[0,2] }; (aslice2()) = ("ok", "already"); is("@array2", "ok B already d"); %hash = qw(a Alpha b Beta c Gamma); sub hslice : lvalue { @hash{"c", "b"} } (hslice()) = ("CISC", "BogoMIPS"); is(join("/",@hash{"c","a","b"}), "CISC/Alpha/BogoMIPS"); } $str = "Hello, world!"; sub sstr : lvalue { substr($str, 1, 4) } sstr() = "i"; is($str, "Hi, world!"); $str = "Made w/ JavaScript"; sub veclv : lvalue { vec($str, 2, 32) } if (ord('A') != 193) { veclv() = 0x5065726C; } else { # EBCDIC? veclv() = 0xD7859993; } is($str, "Made w/ PerlScript"); sub position : lvalue { pos } @p = (); $_ = "fee fi fo fum"; while (/f/g) { push @p, position; position() += 6; } is("@p", "1 8"); sub keeze : lvalue { keys %__ } %__ = ("a","b"); keeze = 64; is scalar %__, '1/64', 'keys assignment through lvalue sub'; # Bug 20001223.002: split thought that the list had only one element @ary = qw(4 5 6); sub lval1 : lvalue { $ary[0]; } sub lval2 : lvalue { $ary[1]; } (lval1(), lval2()) = split ' ', "1 2 3 4"; is(join(':', @ary), "1:2:6"); # check that an element of a tied hash/array can be assigned to via lvalueness package Tie_Hash; our ($key, $val); sub TIEHASH { bless \my $v => __PACKAGE__ } sub STORE { ($key, $val) = @_[1,2] } package main; sub lval_tie_hash : lvalue { tie my %t => 'Tie_Hash'; $t{key}; } eval { lval_tie_hash() = "value"; }; is($@, "", "element of tied hash"); is("$Tie_Hash::key-$Tie_Hash::val", "key-value"); package Tie_Array; our @val; sub TIEARRAY { bless \my $v => __PACKAGE__ } sub STORE { $val[ $_[1] ] = $_[2] } package main; sub lval_tie_array : lvalue { tie my @t => 'Tie_Array'; $t[0]; } eval { lval_tie_array() = "value"; }; is($@, "", "element of tied array"); is ($Tie_Array::val[0], "value"); # Check that tied pad vars that are returned can be assigned to sub TIESCALAR { bless [] } sub STORE {$wheel = $_[1]} sub FETCH {$wheel} sub tied_pad_var :lvalue { tie my $tyre, ''; $tyre } sub tied_pad_varr :lvalue { tie my $tyre, ''; return $tyre } tied_pad_var = 1; is $wheel, 1, 'tied pad var returned in scalar lvalue context'; tied_pad_var->${\sub{ $_[0] = 2 }}; is $wheel, 2, 'tied pad var returned in scalar ref context'; (tied_pad_var) = 3; is $wheel, 3, 'tied pad var returned in list lvalue context'; $_ = 4 for tied_pad_var; is $wheel, 4, 'tied pad var returned in list ref context'; tied_pad_varr = 5; is $wheel, 5, 'tied pad var explicitly returned in scalar lvalue context'; tied_pad_varr->${\sub{ $_[0] = 6 }}; is $wheel, 6, 'tied pad var explicitly returned in scalar ref context'; (tied_pad_varr) = 7; is $wheel, 7, 'tied pad var explicitly returned in list lvalue context'; $_ = 8 for tied_pad_varr; is $wheel, 8, 'tied pad var explicitly returned in list ref context'; # Test explicit return of lvalue expression { # subs are copies from tests 1-~18 with an explicit return added. # They used not to work, which is why they are ‘badly’ named. sub bad_get_lex : lvalue { return $in }; sub bad_get_st : lvalue { return $blah } sub bad_id : lvalue { return ${\shift} } sub bad_id1 : lvalue { return $_[0] } sub bad_inc : lvalue { return ${\++$_[0]} } $in = 5; $blah = 3; bad_get_st = 7; is( $blah, 7 ); bad_get_lex = 7; is($in, 7, "yada"); ++bad_get_st; is($blah, 8, "yada"); ++bad_get_lex; cmp_ok($in, '==', 8); bad_id(bad_get_st) = 10; cmp_ok($blah, '==', 10); bad_id(bad_get_lex) = 10; cmp_ok($in, '==', 10); ++bad_id(bad_get_st); cmp_ok($blah, '==', 11); ++bad_id(bad_get_lex); cmp_ok($in, '==', 11); bad_id1(bad_get_st) = 20; cmp_ok($blah, '==', 20); bad_id1(bad_get_lex) = 20; cmp_ok($in, '==', 20); ++bad_id1(bad_get_st); cmp_ok($blah, '==', 21); ++bad_id1(bad_get_lex); cmp_ok($in, '==', 21); bad_inc(bad_get_st); cmp_ok($blah, '==', 22); bad_inc(bad_get_lex); cmp_ok($in, '==', 22); bad_inc(bad_id(bad_get_st)); cmp_ok($blah, '==', 23); bad_inc(bad_id(bad_get_lex)); cmp_ok($in, '==', 23); ++bad_inc(bad_id1(bad_id(bad_get_st))); cmp_ok($blah, '==', 25); ++bad_inc(bad_id1(bad_id(bad_get_lex))); cmp_ok($in, '==', 25); # Recursive my $r; my $to_modify; $r = sub :lvalue { my $depth = shift//0; if ($depth == 2) { return $to_modify } return &$r($depth+1); }; &$r(0) = 7; is $to_modify, 7, 'recursive lvalue sub'; # Recursive with substr [perl #72706] my $val = ''; my $pie; $pie = sub :lvalue { my $depth = shift; return &$pie($depth) if $depth--; substr $val, 0; }; for my $depth (0, 1, 2) { my $value = "Good $depth"; eval { &$pie($depth) = $value; }; is($@, '', "recursive lvalue substr return depth $depth"); is($val, $value, "value assigned to recursive lvalue substr (depth $depth)"); } } { # bug #23790 my @arr = qw /one two three/; my $line = "zero"; sub lval_array () : lvalue {@arr} for (lval_array) { $line .= $_; } is($line, "zeroonetwothree"); sub trythislval { scalar(@_)."x".join "", @_ } is(trythislval(lval_array()), "3xonetwothree"); sub changeme { $_[2] = "free" } changeme(lval_array); is("@arr", "one two free"); # test again, with explicit return sub rlval_array() : lvalue {return @arr} @arr = qw /one two three/; $line = "zero"; for (rlval_array) { $line .= $_; } is($line, "zeroonetwothree"); is(trythislval(rlval_array()), "3xonetwothree"); changeme(rlval_array); is("@arr", "one two free"); # Variations on the same theme, with multiple vars returned my $scalar = 'half'; sub lval_scalar_array () : lvalue { $scalar, @arr } @arr = qw /one two three/; $line = "zero"; for (lval_scalar_array) { $line .= $_; } is($line, "zerohalfonetwothree"); is(trythislval(lval_scalar_array()), "4xhalfonetwothree"); changeme(lval_scalar_array); is("@arr", "one free three"); sub lval_array_scalar () : lvalue { @arr, $scalar } @arr = qw /one two three/; $line = "zero"; $scalar = 'four'; for (lval_array_scalar) { $line .= $_; } is($line, "zeroonetwothreefour"); is(trythislval(lval_array_scalar()), "4xonetwothreefour"); changeme(lval_array_scalar); is("@arr", "one two free"); # Tests for specific ops not tested above # rv2av @array2 = qw 'one two free'; is join(',', map $_, sub:lvalue{@array2}->()), 'one,two,free', 'rv2av in reference context'; is join(',', map $_, sub:lvalue{@{\@array2}}->()), 'one,two,free', 'rv2av-with-ref in reference context'; # padhv my %hash = qw[a b c d]; like join(',', map $_, sub:lvalue{%hash}->()), qr/^(?:a,b,c,d|c,d,a,b)\z/, 'padhv in reference context'; # rv2hv %hash2 = qw[a b c d]; like join(',', map $_, sub:lvalue{%hash2}->()), qr/^(?:a,b,c,d|c,d,a,b)\z/, 'rv2hv in reference context'; like join(',', map $_, sub:lvalue{%{\%hash2}}->()), qr/^(?:a,b,c,d|c,d,a,b)\z/, 'rv2hv-with-ref in reference context'; } { package Foo; sub AUTOLOAD :lvalue { *{$AUTOLOAD} }; package main; my $foo = bless {},"Foo"; my $result; $foo->bar = sub { $result = "bar" }; $foo->bar; is ($result, 'bar', "RT #41550"); } SKIP: { skip 'no attributes.pm', 1 unless eval 'require attributes'; fresh_perl_is(<<'----', <<'====', "lvalue can not be set after definition. [perl #68758]"); use warnings; our $x; sub foo { $x } sub foo : lvalue; sub MODIFY_CODE_ATTRIBUTES {} sub foo : lvalue : fr0g; foo = 3; ---- lvalue attribute ignored after the subroutine has been defined at - line 4. lvalue attribute ignored after the subroutine has been defined at - line 6. Can't modify non-lvalue subroutine call in scalar assignment at - line 7, near "3;" Execution of - aborted due to compilation errors. ==== } { my $x; sub lval_decl : lvalue; sub lval_decl { $x } lval_decl = 5; is($x, 5, "subroutine declared with lvalue before definition retains lvalue. [perl #68758]"); } SKIP: { skip "no attributes.pm", 2 unless eval { require attributes }; sub utf8::valid :lvalue; require attributes; is "@{[ &attributes::get(\&utf8::valid) ]}", 'lvalue', 'sub declaration with :lvalue applies it to XSUBs'; BEGIN { *wonky = \&marjibberous } sub wonky :lvalue; is "@{[ &attributes::get(\&wonky) ]}", 'lvalue', 'sub declaration with :lvalue applies it to assigned stub'; } sub fleen : lvalue { $pnare } $pnare = __PACKAGE__; ok eval { fleen = 1 }, "lvalues can return COWs (CATTLE?) [perl #75656]";\ is $pnare, 1, 'and returning CATTLE actually works'; $pnare = __PACKAGE__; ok eval { (fleen) = 1 }, "lvalues can return COWs in list context"; is $pnare, 1, 'and returning COWs in list context actually works'; $pnare = __PACKAGE__; ok eval { $_ = 1 for(fleen); 1 }, "lvalues can return COWs in ref cx"; is $pnare, 1, 'and returning COWs in reference context actually works'; # Returning an arbitrary expression, not necessarily lvalue +sub :lvalue { return $ambaga || $ambaga }->() = 73; is $ambaga, 73, 'explicit return of arbitrary expression (scalar context)'; (sub :lvalue { return $ambaga || $ambaga }->()) = 74; is $ambaga, 74, 'explicit return of arbitrary expression (list context)'; +sub :lvalue { $ambaga || $ambaga }->() = 73; is $ambaga, 73, 'implicit return of arbitrary expression (scalar context)'; (sub :lvalue { $ambaga || $ambaga }->()) = 74; is $ambaga, 74, 'implicit return of arbitrary expression (list context)'; eval { +sub :lvalue { return 3 }->() = 4 }; like $@, qr/Can\'t return a readonly value from lvalue subroutine at/, 'assignment to numeric constant explicitly returned from lv sub'; eval { (sub :lvalue { return 3 }->()) = 4 }; like $@, qr/Can\'t return a readonly value from lvalue subroutine at/, 'assignment to num constant explicitly returned (list cx)'; eval { +sub :lvalue { 3 }->() = 4 }; like $@, qr/Can\'t return a readonly value from lvalue subroutine at/, 'assignment to numeric constant implicitly returned from lv sub'; eval { (sub :lvalue { 3 }->()) = 4 }; like $@, qr/Can\'t return a readonly value from lvalue subroutine at/, 'assignment to num constant implicitly returned (list cx)'; # reference (potential lvalue) context $suffix = ''; for my $sub (sub :lvalue {$_}, sub :lvalue {return $_}) { &$sub()->${\sub { $_[0] = 37 }}; is $_, '37', 'lvalue->method'.$suffix; ${\scalar &$sub()} = 38; is $_, '38', 'scalar(lvalue)'.$suffix; sub assign39_with_proto ($) { $_[0] = 39 } assign39_with_proto(&$sub()); is $_, '39', 'func(lvalue) when func has $ proto'.$suffix; $_ = 1; ${\(&$sub()||undef)} = 40; is $_, '40', 'lvalue||...'.$suffix; ${\(${\undef}||&$sub())} = 41; # extra ${\...} to bypass const folding is $_, '41', '...||lvalue'.$suffix; $_ = 0; ${\(&$sub()&&undef)} = 42; is $_, '42', 'lvalue&&...'.$suffix; ${\(${\1}&&&$sub())} = 43; is $_, '43', '...&&lvalue'.$suffix; ${\(&$sub())[0]} = 44; is $_, '44', '(lvalue)[0]'.$suffix; } continue { $suffix = ' (explicit return)' } # autovivification $suffix = ''; for my $sub (sub :lvalue {$_}, sub :lvalue {return $_}) { undef $_; &$sub()->[3] = 4; is $_->[3], 4, 'func->[...] autovivification'.$suffix; undef $_; &$sub()->{3} = 4; is $_->{3}, 4, 'func->{...} autovivification'.$suffix; undef $_; ${&$sub()} = 4; is $$_, 4, '${func()} autovivification' .$suffix; undef $_; @{&$sub()} = 4; is "@$_", 4, '@{func()} autovivification' .$suffix; undef $_; %{&$sub()} = (4,5); is join('-',%$_), '4-5', '%{func()} autovivification'.$suffix; undef $_; ${ (), &$sub()} = 4; is $$_, 4, '${ (), func()} autovivification' .$suffix; } continue { $suffix = ' (explicit return)' } # [perl #92406] [perl #92290] Returning a pad var in rvalue context $suffix = ''; for my $sub ( sub :lvalue { my $x = 72; $x }, sub :lvalue { my $x = 72; return $x } ) { is scalar(&$sub), 72, "sub returning pad var in scalar context$suffix"; is +(&$sub)[0], 72, "sub returning pad var in list context$suffix"; } continue { $suffix = ' (explicit return)' } # Returning read-only values in reference context $suffix = ''; for ( sub :lvalue { $] }->(), sub :lvalue { return $] }->() ) { is \$_, \$], 'read-only values are returned in reference context' .$suffix # (they used to be copied) } continue { $suffix = ' (explicit return)' } # Returning unwritables from nested lvalue sub call in in rvalue context # First, ensure we are testing what we think we are: if (!Internals::SvREADONLY($])) { Internals::SvREADONLY($],1); } sub squibble : lvalue { return $] } sub squebble : lvalue { squibble } sub squabble : lvalue { return squibble } is $x = squebble, $], 'returning ro from nested lv sub call in rv cx'; is $x = squabble, $], 'explct. returning ro from nested lv sub in rv cx'; is \squebble, \$], 'returning ro from nested lv sub call in ref cx'; is \squabble, \$], 'explct. returning ro from nested lv sub in ref cx'; # [perl #102486] Sub calls as the last statement of an lvalue sub package _102486 { my $called; my $x = 'nonlv'; sub strictlv :lvalue { use strict 'refs'; &$x } sub lv :lvalue { &$x } sub nonlv { ++$called } eval { strictlv }; ::like $@, qr/^Can't use string \("nonlv"\) as a subroutine ref while/, 'strict mode applies to sub:lvalue{ &$string }'; $called = 0; ::ok eval { lv }, 'sub:lvalue{&$x}->() does not die for non-lvalue inner sub call'; ::is $called, 1, 'The &$x actually called the sub'; eval { +sub :lvalue { &$x }->() = 3 }; ::like $@, qr/^Can't modify non-lvalue subroutine call at /, 'sub:lvalue{&$x}->() dies in true lvalue context'; }