[lukaszsamson]

Found with SpecLint on elixir 1.20.4

lib/localize/collation/normalizer.ex:58: warning: Localize.Collation.Normalizer.to_codepoints/1: inferred return includes (non_empty_list(term(), term()) and not non_empty_list(integer())) or empty_list(), which the spec does not declare
    @spec to_codepoints(String.t()) :: [non_neg_integer(), ...]
    inferred: (binary()) -> dynamic(empty_list() or non_empty_list(term(), term()))

Localize.Collation.Normalizer.to_codepoints("") #=> [], but the spec declared a non-empty list. The spec is now [non_neg_integer()].