$Data::Dumper::Indent is fully qualified , you don't need resp. can't declare it.

Workarounds:

• you can disable the specific warning
• eval the use and your settings

D:\tmp>perl
use strict;
use warnings;
eval <<'__CODE__';
    use Data::Dumper;
    $Data::Dumper::Indent = 0;
__CODE__
__END__

D:\tmp>
[download]

update

Full demo:

NB: in order to use Dumper w/o parens or leading '&'-sigil you will need to declare it at compile time with subs

D:\tmp>perl
use strict;
use warnings;
#use subs qw/Dumper/;

eval <<'__CODE__';
    use Data::Dumper;
    $Data::Dumper::Indent = 0;
__CODE__

print Dumper( [map {{$_=>$a++}} "a".."d"] );

__END__
$VAR1 = [{'a' => 0},{'b' => 1},{'c' => 2},{'d' => 3}];
D:\tmp>
[download]

---

---

Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!

Titles consisting of a single word are discouraged, and in most cases are disallowed outright.

Read Where should I post X? if you're not absolutely sure you're posting in the right place.

Please read these before you post! —

• How do I compose an effective node title?
• How do I post a question effectively?
• Markup in the Monastery

Posts may use any of the Perl Monks Approved HTML tags:

a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr

You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)

	For:		Use:
	&		&
	<		&lt;
	>		&gt;
	[		&#91;
	]		&#93;

Link using PerlMonks shortcuts! What shortcuts can I use for linking?

See Writeup Formatting Tips and other pages linked from there for more info.