Hello, `x` is `undefined` after executing `let x = async x => { for await ( { x } of [ 0 ] ) ; } ; x ( ) ;` in WebKit JSC, but I think that it is expected to be `async x => ....`: --- $ jsc >>> let x = async x => { for await ( { x } of [ 0 ] ) ; } ; x ( ) ; [object Promise] >>> x undefined >>> --- while other engines behave like: --- # V8 V8 version 10.9.0 d8> let x = async x => { for await ( { x } of [ 0 ] ) ; } ; x ( ) ; [object Promise] d8> x async x => { for await ( { x } of [ 0 ] ) ; } d8> --- WebKit version: 615.1.10