A possibly helpful test:

c:\@Work\Perl\monks>perl -le
"use warnings;
 use strict;
 ;;
 use Test::More 'no_plan';
 use Test::NoWarnings;
 ;;
 note 'perl version: ', $];
 ;;
 @_ = qw(a b c);
 note 'raw print list context shift: ', (shift @_)[ 0, 0, 0 ];
 ;;
 @_ = qw(a b c);
 ok 'aaa' eq join('', (shift @_)[ 0, 0, 0 ]), 'joined shift';
 ;;
 @_ = qw(a b c);
 my @ra = (shift @_)[ 0, 0, 0 ];
 is_deeply \@ra, [ 'a', 'a', 'a' ], 'assigned shift';
 ;;
 @ra = ('x', 'y', 'z')[ 0, 0, 0 ];
 is_deeply \@ra, [ 'x', 'x', 'x' ], 'assigned list';
 ;;
 done_testing;
"
# perl version: 5.014004
# raw print list context shift: aaa
ok 1 - joined shift
not ok 2 - assigned shift
#   Failed test 'assigned shift'
#   at -e line 1.
#     Structures begin differing at:
#          $got->[1] = undef
#     $expected->[1] = 'a'
ok 3 - assigned list
1..3
ok 4 - no warnings
1..4
# Looks like you failed 1 test of 4.
[download]

Update: The problem seems to have been localized between about versions 5.14.x and 5.18.x inclusive so the following may be irrelevant, but just for the heck of it, the code above passes all tests for ActiveState 5.008009 and Strawberries 5.010001 and 5.012003, all running under Windows 7.

> I sent a perlbug message with a link to this node.(

Please correct me, but as far as I understood this thread, does the bug not appear in newer Perl versions.

Do you expect patches for older versions?

Or is it just for documentation?

Cheers Rolf
_{(addicted to the Perl Programming Language :)
Wikisyntax for the Monastery FootballPerl is like chess, only without the dice}

Just for documentation

Nice work. This is why Perl is by far the best language around; teamwork and dedication.

Another oddity: the problematic behavior seems to be associated with assignment to a freshly declared lexical:

c:\@Work\Perl\monks>perl -le
"use warnings;
 use strict;
 ;;
 use Test::More 'no_plan';
 use Test::NoWarnings;
 ;;
 note 'perl version: ', $];
 ;;
 @_ = qw(a b c d e f g);
 ;;
 note 'assign to a fresh lexical';
 ;;
 my @ra = (shift @_)[ 0, 0, 0 ];
 is_deeply \@ra, [ 'a', 'a', 'a' ], '1st = (shift)[slice] to my @ra';
 ;;
 @ra = (shift @_)[ 0, 0, 0 ];
 is_deeply \@ra, [ 'b', 'b', 'b' ], '2nd = (shift)[slice] to @ra';
 ;;
 note 'now another lexical';
 ;;
 my @rb = (shift @_)[ 0, 0, 0 ];
 is_deeply \@rb, [ 'c', 'c', 'c' ], '1st = (shift)[slice] to my @rb';
 ;;
 @rb = (shift @_)[ 0, 0, 0 ];
 is_deeply \@rb, [ 'd', 'd', 'd' ], '2nd = (shift)[slice] to @rb';
 ;;
 @rb = (shift @_)[ 0, 0, 0 ];
 is_deeply \@rb, [ 'e', 'e', 'e' ], '3rd = (shift)[slice] to @rb';
 ;;
 done_testing;
"
# perl version: 5.014004
# assign to a fresh lexical
not ok 1 - 1st = (shift)[slice] to my @ra
#   Failed test '1st = (shift)[slice] to my @ra'
#   at -e line 1.
#     Structures begin differing at:
#          $got->[1] = undef
#     $expected->[1] = 'a'
ok 2 - 2nd = (shift)[slice] to @ra
# now another lexical
not ok 3 - 1st = (shift)[slice] to my @rb
#   Failed test '1st = (shift)[slice] to my @rb'
#   at -e line 1.
#     Structures begin differing at:
#          $got->[1] = undef
#     $expected->[1] = 'c'
ok 4 - 2nd = (shift)[slice] to @rb
ok 5 - 3rd = (shift)[slice] to @rb
1..5
ok 6 - no warnings
1..6
# Looks like you failed 2 tests of 6.
[download]

All three produce aa on my Perl 5.26.1 running on my Linux Mint workstation. What version of Perl are you running yours under?

spek@scelia ~/scratch $ perl -le '@_ = qw( a b c ); print( ( shift @_ 
+)[ 0, 0 ] );'
aa
spek@scelia ~/scratch $ perl -le '@_ = qw( a b c ); @A = ( shift @_ )[
+ 0, 0 ]; print @A'
aa
spek@scelia ~/scratch $ perl -le '@_ = qw( a b c ); @A = ( shift @_ ) 
+x 2; print @A'
aa
spek@scelia ~/scratch $ perl -v

This is perl 5, version 26, subversion 1 (v5.26.1) built for x86_64-li
+nux
[download]

Looks like some kind of change somewhere between 5.18.4 and 5.20.3:

[~]$ perlbrew exec perl -le '@_ = qw( a b c ); @A = ( shift @_ )[ 0, 0
+ ]; print @A'
[...]
perl-5.22.2
==========
aa


perl-5.20.3
==========
aa


perl-5.18.4
==========
a


perl-5.16.3
==========
a


perl-5.14.4
==========
a
[download]

I confirm these findings (on Perl running on Windows at least).

> berrybrew exec perl -le "@_ = qw( a b c ); @A = ( shift @_ )[ 0, 0 ]
+; print @A"

perl-5.28.1_64
==============
aa
perl-5.20.3_64
==============
aa
perl-5.18.4_64
==============
a
[download]

This is perl 5, version 18, subversion 2 (v5.18.2)

Ok. I'll do some installs of other versions on Linux and Windows and try to get to the version where it's borked while I finish my work day. On my Windows system I sometimes develop on, with 5.28.1, I get the aa as well:

c:\repos\berrybrew>perl -le "@_ = qw( a b c ); print( ( shift @_ )[ 0,
+ 0 ] );"
aa

c:\repos\berrybrew>perl -le "@_ = qw( a b c ); @A = ( shift @_ )[ 0, 0
+ ]; print @A"
aa

c:\repos\berrybrew>perl -v

This is perl 5, version 28, subversion 1 (v5.28.1) built for MSWin32-x
+64-multi-thread
[download]

I got the same thing with perl 5, version 18, subversion 1 (v5.18.1) built for x86_64-linux-thread-multi