Probably, I need to fix this from Pry's side, too.
 pry(main)> $ Hash#
NameError: undefined local variable or method `cannot_locate_source_error' for #<Pry::Command::ShowSource:0x9631e48>
from /home/curacao/.gem/ruby/1.9.3/gems/pry-0.9.12/lib/pry/commands/show_source.rb:28:in `content_for'
With pry-doc HEAD it works on Ruby 2.0.0-p0.
It turned out that was a YARD's issue. I sent a pull request fixing this. lsegal/yard#668
It was merged, so this issue is fixed, too.