Issue #21660 has been updated by Earlopain (Earlopain _). Sorry, I forgot about your comment on https://github.com/ruby/prism/pull/3674. https://github.com/ruby/prism/pull/3700 will fix this ---------------------------------------- Bug #21660: No-parentheses endless method definition that has parameter destructuring is wrongly accepted in Prism https://bugs.ruby-lang.org/issues/21660#change-115021 * Author: tompng (tomoya ishida) * Status: Open * Assignee: prism * ruby -v: ruby 3.5.0dev (2025-11-01T00:18:01Z master 17a7b4e031) +PRISM [x86_64-linux] * Backport: 3.2: UNKNOWN, 3.3: UNKNOWN, 3.4: UNKNOWN ---------------------------------------- This is syntax error in parse.y but not in Prism. ~~~ruby def f a, (b) = 1 ~~~ Related to #21623 -- https://bugs.ruby-lang.org/