According the WebIDL spec [1] this is valid but is currently rejected by WebKit's IDL Parser. [1] https://webidl.spec.whatwg.org/#SecureContext
Created attachment 453687 [details] Patch
<rdar://problem/89725581>
Comment on attachment 453687 [details] Patch Neat!
Committed r290803 (248043@main): <https://commits.webkit.org/248043@main> All reviewed patches have been landed. Closing bug and clearing flags on attachment 453687 [details].