Issue #18551 has been updated by mame (Yusuke Endoh). In the previous dev meething, matz accepted this. I will merge the PR ---------------------------------------- Feature #18551: Make `Range#reverse_each` to raise an exception if endless https://bugs.ruby-lang.org/issues/18551#change-105427 * Author: kyanagi (Kouhei Yanagita) * Status: Open * Priority: Normal ---------------------------------------- https://github.com/ruby/ruby/pull/5498 Currently, `Range#reverse_each` for an endless range never returns. ``` % ruby -e '(1..).reverse_each { }' # never return ... ``` (This is because `Enumerable#reverse_each` tries `#to_a` and `#to_a` for an endless range comes into an infinite loop.) I think `Range#reverse_each` for an endless range should raise an exception, similar to `Range#each` for a beginless range. ``` % ruby -e '(..1).each { }' -e:1:in `each': can't iterate from NilClass (TypeError) from -e:1:in `<main>' ``` -- https://bugs.ruby-lang.org/