Issue #20945 has been updated by ufuk (Ufuk Kayserilioglu). `Parser::CurrentRuby` is coming from the [parser gem](https://github.com/whitequark/parser), and has nothing to do with parse.y, it is pure Ruby implementation of a Ruby parser. If you think the AST of Prism should behave differently, please open an issue on the https://github.com/ruby/prism repo itself. ---------------------------------------- Bug #20945: Behaviour mismatch between parse.y and prism with character literals AST nodes https://bugs.ruby-lang.org/issues/20945#change-110939 * Author: viralpraxis (Iaroslav Kurbatov) * Status: Open * ruby -v: ruby 3.3.6 (2024-11-05 revision 75015d4c1f) [x86_64-linux] * Backport: 3.1: UNKNOWN, 3.2: UNKNOWN, 3.3: UNKNOWN ---------------------------------------- AST string node (character literals) values returned by parse.y are, for some reason, frozen, whereas Prism does not freeze them: ``` ruby require 'prism' require 'parser/current' puts Prism::VERSION puts Parser::VERSION p Prism.parse('?a').value.statements.child_nodes.first.content.then { [_1.class, _1.frozen?] } p Parser::CurrentRuby.parse('?a').children[0].then { [_1.class, _1.frozen? ]} p Prism.parse('?\n').value.statements.child_nodes.first.content.then { [_1.class, _1.frozen?] } p Parser::CurrentRuby.parse('?\n').children[0].then { [_1.class, _1.frozen? ]} ``` output: ``` 1.2.0 3.3.6.0 [String, false] [String, false] [String, false] [String, true] ``` I’m not sure whether this is a bug in Parser, Prism, or something else. -- https://bugs.ruby-lang.org/