it's the 25% that bite us (both):

rj@pollux:~/_ELRIC/implementation/src/examples> perl -MO=Xref -we 1
File -e
  Subroutine (definitions)
    Package UNIVERSAL
      &VERSION          s0
      &can              s0
      &isa              s0
    Package attributes
      &bootstrap        s0
-e syntax OK
[download]

Use of uninitialized value in string eq at /usr/lib/perl5/5.6.1/i586-l
+inux/B/Xref.pm line 117.
Use of uninitialized value in substitution (s///) at /usr/lib/perl5/5.
+6.1/i586-linux/B/Xref.pm line 124.
Use of uninitialized value in string eq at /usr/lib/perl5/5.6.1/i586-l
+inux/B/Xref.pm line 117.
Use of uninitialized value in substitution (s///) at /usr/lib/perl5/5.
+6.1/i586-linux/B/Xref.pm line 124.
Use of uninitialized value in concatenation (.) or string at /usr/lib/
+perl5/5.6.1/i586-linux/B/Xref.pm line 130.
Use of uninitialized value in string eq at /usr/lib/perl5/5.6.1/i586-l
+inux/B/Xref.pm line 117.
etc. etc. (cut for node readability)
Use of uninitialized value in substitution (s///) at /usr/lib/perl5/5.
+6.1/i586-linux/B/Xref.pm line 124.
Use of uninitialized value in concatenation (.) or string at /usr/lib/
+perl5/5.6.1/i586-linux/B/Xref.pm line 130.
Use of uninitialized value in concatenation (.) or string at /usr/lib/
+perl5/5.6.1/i586-linux/B/Xref.pm line 130.
[download]

Update:

I thought B::Xref spills out human readable output by default (no params).. :-) Is this considered human readable?

  Subroutine deflate
    Package (lexical)
      $$eref            51
      $@$$eref          56
      $@$@$$eref        60
      $@$@$@$$eref      65
      $@$@$@$@$$eref    70
      $eref             i50, 51
      $i                i55, 56, 59, 59, 55, 70, 71
      $inner            i60, 62, 63, 64, 55, 69
      $j                i59, 60, 65, 66, 67, 59
      $key              i49
      $outer            i56, 62, 63, 64, 55, 69
      $size             i51, 66, 59, 55, 71
      @$$eref           51, 56
      @$@$$eref         56, 60
      @$@$@$$eref       60, 65
      @$@$@$@$$eref     65, 70
      @$@$@$@$@$$eref   70
    Package main
      @_                49, 50
[download]

Bye
 PetaMem

Edit by tye to change PRE tags to CODE tags

You're right, things are worse than I thought. And yes, cross-referencing usage starts from large ammount of code.

Anyway, did you tried latest perl (5.8.0-RC1)?
Just curious.
Also, thank you for your experience, with your help I will be careful when will be planning using any compiler stuff.

Courage, the Cowardly Dog.
PS. Something fishy is going on there, or my name is Vadim Konovalov. And it's not.