Issue #22264 has been updated by k0kubun (Takashi Kokubun). Backport changed from 3.3: REQUIRED, 3.4: REQUIRED, 4.0: REQUIRED to 3.3: REQUIRED, 3.4: REQUIRED, 4.0: DONE ruby_4_0 commit:310533c5a207db00382cc764775ca91e06acb17c merged revision(s) commit:e5132b162737829f744b2b23908b9d08479db977. ---------------------------------------- Bug #22264: Warning missing from parse.y hash literals https://bugs.ruby-lang.org/issues/22264#change-119001 * Author: kddnewton (Kevin Newton) * Status: Closed * Backport: 3.3: REQUIRED, 3.4: REQUIRED, 4.0: DONE ---------------------------------------- $ ruby --parser=parse.y -cve '{**{}, a: 1, **{a: 2}}' ruby 4.1.0dev (2026-04-21T02:07:14Z aot be86d5704f) [arm64-darwin23] Syntax OK $ ruby --parser=parse.y -cve '{a: 1, **{a: 2}}' ruby 4.1.0dev (2026-04-21T02:07:14Z aot be86d5704f) [arm64-darwin23] -e:1: warning: key :a is duplicated and overwritten on line 1 Syntax OK -- https://bugs.ruby-lang.org/