187045 2018-06-26 08:16:04 -0700 Inconsistent output compared with other JS engines 2018-07-22 13:04:26 -0700 1 1 1 Unclassified WebKit JavaScriptCore WebKit Local Build Unspecified Unspecified NEW P2 Normal --- 1 sunlili webkit-unassigned ysuzuki oldest_to_newest 1436500 0 sunlili 2018-06-26 08:16:04 -0700 Hello, The following code behaves strangely (inconsistent with other engines). class cc extends ( x = function () { console.log("Hi"); }) { }; In webkit, cc is defined normally and x is defined too. However, in V8 and Firefox, a ReferenceError is reported: ReferenceError: assignment to undeclared variable x BT group 2018.6.26 1444169 1 ysuzuki 2018-07-22 13:04:26 -0700 *** Bug 187758 has been marked as a duplicate of this bug. ***