You might want to consider re-working your logic.

@to_search = qw' /exists /doesnt-exist ';   # master list

find( { wanted => \&wanted, bydepth => 0 }, grep { -d } @to_search);
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If you REALLY need to know which ones don't exist, consider grepping that out beforehand.

@not_found = grep { ! -d } @to_search;
warn "Not found: " . join(", ", @not_found) . "\n" if @not_found;
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