Ruby vs. Crystal Performance
Crystal and Ruby do not even remotely have the same semantics. They look similar but the similarity is extremely superficial. The extra semantics that Ruby has have a massive impact on performance, for even the most optimising implementations. This is not a reasonable comparison if you do not consider the 'slick as Ruby' part. No runtime metaprogramming! The entire Ruby ecosystem is built on runtime metaprogramming!(Crystal is a fine language and compiler - but it's nothing to do with Ruby.)