in reply to Re^5: eval, Read environment variable and expand using eval
in thread eval, Read environment variable and expand using eval

Both exists and defined still can autovivify on deep hashes though.

No, it's the dereference operator that does the autovivification. Any autovivification occurs before defined and exists are called. 

$ perl -MData::Dumper -e'$h{notexist}{baz}; print Dumper \%h'
$VAR1 = {
          'notexist' => {}
        };

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