See ES5.1 8.12.9 10.a.i - the spec prohibits making a read-only property writable, but does not inhibit making a writable property read-only.
Created attachment 128095 [details] Fix
Comment on attachment 128095 [details] Fix View in context: https://bugs.webkit.org/attachment.cgi?id=128095&action=review > Source/JavaScriptCore/ChangeLog:3 > + Should be able to reconfigure a non-configurable property as writable This title contradicts the description below. > Source/JavaScriptCore/runtime/JSGlobalData.h:252 > - > + Why? > Source/JavaScriptCore/runtime/JSGlobalData.h:370 > + bool m_inDefineOwnProperty; > + > + This whitespace is not all needed.
Fixed in r108427