Issue #22264 has been updated by nobu (Nobuyoshi Nakada). Backport changed from 3.3: UNKNOWN, 3.4: UNKNOWN, 4.0: UNKNOWN to 3.3: REQUIRED, 3.4: REQUIRED, 4.0: REQUIRED I agree with Jeremy's concern, but I think it should be discussed separately. As for this bug, it stems from an oversight when we allowed `**` to be placed in locations other than the end of a hash literal; it should be fixed simply by removing the condition “unless the first element is NULL” from `assocs : assocs ‘,’ assoc`. ---------------------------------------- Bug #22264: Warning missing from parse.y hash literals https://bugs.ruby-lang.org/issues/22264#change-118663 * Author: kddnewton (Kevin Newton) * Status: Open * Backport: 3.3: REQUIRED, 3.4: REQUIRED, 4.0: REQUIRED ---------------------------------------- $ 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/