From: Eric Wong <normalperson@...>
Date: 2015-01-18T01:51:33+00:00
Subject: [ruby-core:67665] Re: [ruby-trunk - Misc #10754] [Open] Tiny optimisation of Set#include?

This speedup probably happens because Hash#[] has an optimized dispatch
VM instruction (opt_aref in insns.def) while Hash#include? does not.

Seems like an OK change to make, I'll commit in a few days unless others
raise objections.