[ruby-core:35599] Proc#== behaviour on 1.8.7 and 1.9.2

I've encountered a problem when using Proc#== (with both lambdas and
procs) in my code, where the result does not match up with what the
documentation says. 1.9.2 differs from 1.8.7 in result and in the
source code, so that suggests attention has been given to the method,
at least. It was suggested that ruby-core was the place to go for
this.

Here's a paste of the problem, with full RUBY_DESCRIPTIONs:
https://gist.github.com/899026

I've included lambda, proc, and Proc.new variants just for completion,
even though I realise proc is an alias for lambda or Proc.new,
depending.

At the very least, perhaps someone could explain why this is by
design, if it's not a bug. Apologies if there's an open issue for this
on redmine; the site is currently not working for me (again), and I
couldn't find anything online mentioning this.