Issue #20764 has been reported by tompng (tomoya ishida). ---------------------------------------- Bug #20764: Forwarding parameter `...` is wrongly allowed in lambda https://bugs.ruby-lang.org/issues/20764 * Author: tompng (tomoya ishida) * Status: Open * ruby -v: ruby 3.4.0dev (2024-09-27T00:58:32Z master 0c25eb4ffe) +PRISM [x86_64-linux] * Backport: 3.1: UNKNOWN, 3.2: UNKNOWN, 3.3: UNKNOWN ---------------------------------------- These codes are all syntax error ~~~ruby ->...{} ->(...){} ->(a,...){} ~~~ But these are allowed in --parser=parse.y. It should be syntax error ~~~ruby ->a,...{} ->(a=1,...){} ~~~ ~~~ # ruby --parser=parse.y -e "p ->a,...{}.parameters" [[:opt, :b], [:rest, :*], [:keyrest, :**], [:block, :&]] # ruby --parser=parse.y -e "p ->(a=1,...){}.parameters" [[:opt, :b], [:rest, :*], [:keyrest, :**], [:block, :&]] # ruby --parser=parse.y -e "p ->(a,...){}.parameters" -e:1: syntax error, unexpected ... p ->(a,...){}.parameters ruby: compile error (SyntaxError) ~~~ -- https://bugs.ruby-lang.org/