Parameter of async function is undefined if it reassigned later

Created attachment 470434 [details]
A short html snippet to reproduce the issue

Consider the following async function:


  async function test_1(a) {
    console.log(a)
    var a = a === 0 ? 1 : 2;
    console.log(a)
  }
  
  test_1(1);

## Expected output: 1 2
## Actual output: undefined 2

Additional note: if the parameter is not reassigned in the function, the console.log prints the correct value. 

Expected output can be tested in Chrome, Firefox, Edge

[Karl Dubost]

I get the same output in the 3 browsers
[Log] 0 (attachment.cgi, line 6)
[Log] 1 (attachment.cgi, line 8)
[Log] 0 (attachment.cgi, line 11)

With 

Safari Technology Preview  190           19619.1.5.5.2
Firefox Nightly            125.0a1       12524.3.12
Google Chrome Canary       125.0.6371.0  6371.0

[Radar WebKit Bug Importer]

<rdar://problem/125416378>

I can confirm that it works in Technology Preview 190. Looking forward to be included in the main build too.

[Karl Dubost]

Thanks!