$ perl -d -e 'sub foo { "bar" }; $o = bless {}, "main"'

Loading DB routines from perl5db.pl version 1.39_10
Editor support available.

Enter h or 'h h' for help, or 'man perldebug' for more help.

main::(-e:1):	sub foo { "bar" }; $o = bless {}, "main"
  DB<1> m $o
foo
via UNIVERSAL: DOES
via UNIVERSAL: VERSION
via UNIVERSAL: can
via UNIVERSAL: isa

  DB<2> m $o, '(?i:o)'
foo
via UNIVERSAL: DOES
via UNIVERSAL: VERSION

  DB<3> m main
foo
via UNIVERSAL: DOES
via UNIVERSAL: VERSION
via UNIVERSAL: can
via UNIVERSAL: isa

  DB<4> m main (?i:o)
foo
via UNIVERSAL: DOES
via UNIVERSAL: VERSION