Issue #19399 has been reported by tompng (tomoya ishida). ---------------------------------------- Bug #19399: Ripper::Lexer.parse throws NoMethodError error for some input https://bugs.ruby-lang.org/issues/19399 * Author: tompng (tomoya ishida) * Status: Open * Priority: Normal * ruby -v: ruby 3.2.0 (2022-12-25 revision a528908271) [x86_64-darwin20] * Backport: 2.7: UNKNOWN, 3.0: UNKNOWN, 3.1: UNKNOWN, 3.2: UNKNOWN ---------------------------------------- Ripper::Lexer.paser throws ``undefined method `flatten!' for nil:NilClass (NoMethodError)`` for this input ~~~ruby require 'ripper' code = <<~CODE a do |b # closing "|" is missing <<~C C end CODE Ripper::Lexer.parse code ~~~ ~~~ /Users/tomoya/.rbenv/versions/3.2.0/lib/ruby/3.2.0/ripper/lexer.rb:183:in `parse': undefined method `flatten!' for nil:NilClass (NoMethodError) result.concat(@buf) until (@buf = []; super(); @buf.flatten!; @buf.empty?) ^^^^^^^^^ from /Users/tomoya/.rbenv/versions/3.2.0/lib/ruby/3.2.0/ripper/core.rb:19:in `parse' from -:8:in `<main>' ~~~ -- https://bugs.ruby-lang.org/