Issue #8923 has been reported by ko1 (Koichi Sasada). ---------------------------------------- Feature #8923: Frozen nil/true/false https://bugs.ruby-lang.org/issues/8923 Author: ko1 (Koichi Sasada) Status: Open Priority: Normal Assignee: matz (Yukihiro Matsumoto) Category: core Target version: current: 2.1.0 Related to [Feature #8906] We aready freezed Integer, Float. Symbols soon (now working). How about to freeze nil, true and false, too? # frozen ruby? "Ruby"f? -- http://bugs.ruby-lang.org/