My guess is auto vivification 
$ perl -wMstrict -le 'sub foo { return @_; }
 ;;
 my $ar;
 print foo(@$ar);
 print $ar;'

ARRAY(0xada8b410)
$

[download]

The aliasing is bypassing the strict check.

Something like this at least ... ;)

Update

  DB<12> use strict;print  @$b
Can't use an undefined value as an ARRAY reference at (eval 39)[/data/
+data/com.termux/files/usr/lib/perl5/5.28.2/perl5db.pl:738] line 2.

  DB<13> use strict;print  @$b=(1..3)
123
  DB<14> p $b
ARRAY(0xb0a92180)
  DB<15>

[download]

I wasn't too wrong, strict tolerates it as long as it is an lvalue. And aliasing seems to have this effect.

HTH! :)

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

In reply to Re: Dereference of undefined value OK under strictures? by LanX
in thread Dereference of undefined value OK under strictures? by AnomalousMonk

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