no, neither exist nor define autovivify. you're treating notexist and notdefined as if they exist and are defined, therefore they are autovivified (start existing, you treat as hash, become hash)

#!/usr/bin/perl --
use strict;
use warnings;
use Data::Dumper;
my %f;
if ( $f{notexist}{baz} ) { warn 1}
if ( $f{notdefined}{baz} ) { warn 1}
die Dumper(\%f);
__END__
$VAR1 = {
          'notexist' => {},
          'notdefined' => {}
        };
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