To continue to use \n, use a list with print ...

Yes. Although I'd use a separate line for clarity

print Dumper $data_structure;
print "\n";
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Just use say:

say Dumper $data_structure;
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say outputs a trailing newline unless the arguments already contain a trailing newline.

I just feel that is clearer and less prone to the sort of error I created.

I'm no Lisp guy, but using a few more brackets helps to avoid ambiguity and misunderstandings between humans and computers. If you call a function or method, add brackets around the argument list. That's what I do, with only very few exceptions - mostly stuff that is listed in perlfunc, but behaves more like a keyword or a C macro (__FILE__, __LINE__, __PACKAGE__, do, eval, package, use, require) than like a function.

I would have written ...

say Dumper($data_structure);
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... in code for perl 5.10 and newer (i.e. with use v5.10 in the file), or ...

print Dumper($data_structure),"\n";
# or
print Dumper($data_structure)."\n";
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... in code for older perls.

Alexander