I'd suggegst Devel::TraceUse:

$ perl -d:TraceUse=hidecore -MCSV -e'dcsv (in => [[1,2]])'
1,2
1
Modules used from -e:
   1.  CSV 1.29, -e line 0 [main]
   2.    Text::CSV_XS 1.29, CSV.pm line 1 [main]
  17.      Config_heavy.pl, Config.pm line 80
  18.        Config_git.pl, Config_heavy.pl line 1366 [Config]
  16.    Data::Peek 0.46, CSV.pm line 2 [main]
  19.      Perl::Tidy 20170521, Data/Peek.pm line 24 (eval 4)
  26.        Encode::ConfigLocal, Encode.pm line 61 (FAILED)
  46.        HTML::Entities 3.69, Perl/Tidy.pm line 4613 (eval 12) [Pe
+rl::Tidy::HtmlWriter]
  47.          HTML::Parser 3.72, HTML/Entities.pm line 152
  49.    JSON 2.93, CSV.pm line 3 [main]
  50.      JSON::XS 3.03, JSON.pm line 266 (eval 13)
  51.        Types::Serialiser 1.0, JSON/XS.pm line 115
Possible proxies:
   2 File/Copy.pm line 18, sub Perl::Tidy::BEGIN
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