If you are using Build.PL define the {requires}{perl} = VERSION field. If you are using MakeMaker (Makefile.PL) you should upgrade ExtUtils::MakeMaker to 6.48 and use MIN_PERL_VERSION parameter. Perl::MinimumVersion can help you determine which version of Perl your module needs.

Define the license if you are using in Build.PL. If you are using MakeMaker (Makefile.PL) you should upgrade to ExtUtils::MakeMaker version 6.31.

Add =head1 LICENSE and/or the proper text of the well-known license to the main module in your code.

Add 'use warnings' (or its equivalents) to all modules, or convince us that your favorite module is well-known enough and people can easily see the modules warn when something bad happens.

Error: RPerl::Algorithm::Combinatorics::BinPacking, RPerl::Algorithm::Combinatorics::BinomialNChooseK, RPerl::Algorithm::Combinatorics::Knapsack, RPerl::Algorithm::Fractal::Julia, RPerl::Algorithm::Fractal::Mandelbrot, RPerl::Algorithm::Graph::MapColoring, RPerl::Algorithm::Graph::Search::AStar, RPerl::Algorithm::Graph::Search::Dijkstra, RPerl::Algorithm::Graph::TravellingSalesman, RPerl::Algorithm::Graph::Tree::Search::BreadthFirst, RPerl::Algorithm::Graph::Tree::Search::DepthFirst, RPerl::Algorithm::Graph::Tree::Search::NearestNeighbor, RPerl::Algorithm::Graph::Tree::Search::Range, RPerl::Algorithm::Math::ConjugateGradient, RPerl::Algorithm::Math::Determinant, RPerl::Algorithm::Math::Discriminant, RPerl::Algorithm::Math::FastFourierTransform, RPerl::Algorithm::Math::GaussJordanElimination, RPerl::Algorithm::Simulation::NBody, RPerl::Algorithm::Sort::Binary, RPerl::Algorithm::Sort::Heap, RPerl::Algorithm::Sort::Radix, RPerl::Algorithm::Sort::Selection, RPerl::CompileUnit::Module::Package::Template, RPerl::DataStructure::Graph::AdjacencyList, RPerl::DataStructure::Graph::Matrix, RPerl::DataStructure::Graph::ObjectPointer, RPerl::DataStructure::Graph::Tree::Binary::AVL, RPerl::DataStructure::Graph::Tree::Binary::RedBlack, RPerl::DataStructure::Graph::Tree::Binary::Splay, RPerl::DataStructure::Graph::Tree::KD, RPerl::DataStructure::Graph::Tree::NAry, RPerl::DataStructure::Graph::Tree::Suffix, RPerl::DataStructure::Graph::Tree::Trie, RPerl::Interpreter, RPerl::Test::Bar, RPerl::Test::Header::Class_00_Bad_01, RPerl::Test::Header::Class_00_Bad_02, RPerl::Test::Header::Package_00_Bad_01, RPerl::Test::Header::Package_00_Bad_02

Ask the owner of the distribution (the one who released it first, or the one who is designated in x_authority) to give you a (co-)maintainer's permission.

Error:

• array
• bool
• char
• float
• hash
• integer
• method
• number
• object
• properties
• ref
• string
• unknown

Fix the version numbers so that version::is_lax($version) returns true.

Error:

• lib/RPerl/Algorithm/Math/GeometricAlgebra.pm: HASH(0x55c8d2a10028)
• lib/RPerl/CompileUnit.pm: HASH(0x55c8d222a528)
• lib/RPerl/DataStructure/CodeReference.pm: HASH(0x55c8d2a01220)
• lib/RPerl/DataStructure/Hash/Properties.pm: HASH(0x55c8d20c2f18)
• lib/RPerl/GrammarRule.pm: HASH(0x55c8cfed3b18)
• lib/RPerl/NonGenerator.pm: HASH(0x55c8d05f37b8)
• lib/RPerl/Operation.pm: HASH(0x55c8d2b99f68)

Split the distribution, or fix the version numbers to make them consistent (use the highest version number to avoid version downgrade).

Error: 0.001,0.001001,0.001003,0.00101,0.001011,0.001021,0.00103,0.00104,0.0011,0.002,0.00201,0.00202,0.002031,0.003,0.003001,0.003011,0.00303,0.00311,0.004001,0.004002,0.004003,0.00401,0.004021,0.004041,0.004043,0.005,0.006011,0.01,0.02003,0.1001,1,100.001

Add all modules contained in this distribution to the META.yml field 'provides'. Module::Build or Dist::Zilla::Plugin::MetaProvides do this automatically for you.

Add a 'repository' resource to the META.yml via 'meta_add' accessor (for Module::Build) or META_ADD parameter (for ExtUtils::MakeMaker).

This is not a critical issue. Currently mainly informative for the CPANTS authors. It might be removed later.