JSXv4: Combining argument alias with default argument causes error

[glennsl]

Repro

@react.component
let make = (~foo as bar="") => <div />

yields the error:

The value foo can't be found

with no location information.

This used to work with JSXv3.

Also note that either feature on its own works fine, it's just the combination that fails:

@react.component
let make = (~foo as bar) => <div />

@react.component
let make = (~foo="") => <div />