my %args = %{ $_[0] };
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my %args = %{ $_[0] };

# or

my %args = %{ +shift };
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Update: The dereference curly braces introduce a new scope, so declaring the variable inside doesn't make sense:

my %args = %{ my $arg = shift };
# Here, $arg doesn't exist.
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($q=q:Sq=~/;[c](.)(.)/;chr(-||-|5+lengthSq)`"S|oS2"`map{chr |+ord
}map{substrSq`S_+|`|}3E|-|`7**2-3:)=~y+S|`+$1,++print+eval$q,q,a,
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and what does + in front of shift do?

The + in front of shift tells Perl that you want the function shift and not a string "shift" as the hash key.

I doubt it's a good idea, since you might still want to pass more positional parameters. Otherwise you could just pass a list func(a=>1) with sub func { my %args = @_}

But for completeness a solution with the new refaliasing feature

use strict;
use warnings;
use Data::Dump qw/pp dd/;

use feature qw/refaliasing/;
no warnings "experimental::refaliasing";


sub tst {
    (\my %args) = @_;
    pp \%args;
}

tst({a=>1,b=>2});
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C:/Perl_524/bin\perl.exe  d:/tmp/pm/refaliasing.pl 
{ a => 1, b => 2 }
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#!/usr/bin/env perl
use strict;
use warnings;
use Data::Dumper;

sub p {
    my %args = shift->%*;
    print Dumper \%args;
}

p({ cow => 'jump', over => 'moon' });
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$VAR1 = {
          'cow' => 'jump',
          'over' => 'moon'
        };
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Yeah,

my ($args) = @_;
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No need to make a copy of the hash!

We don't know what the OP wants to do with the hash. If it is modified in the subroutine, it may need to be copied to prevent spooky action at a distance.

They are free to ignore me in the unlikely situation that what I said doesn't apply to them.